This PDF file contains the front matter associated with SPIE Proceedings Volume 12639, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

This paper proposes a radar reconnaissance simulation design method, which consists of radar reconnaissance decision-making simulation, the main controller of radar reconnaissance simulation, radar reconnaissance simulation, frequency matching simulation, visibility analysis simulation, and reconnaissance process simulation. Combined with the actual project, good results have been achieved.

In order to improve the stability of ground resonance and air resonance of the bearingless rotor helicopter, especially the unstable phenomenon of air resonance may occur in the condition of large overload high-speed flight and maneuvering flight, how to broaden the flight envelope of air stability, the key is to study and master the design parameters or factors that significantly affect the dynamic instability. Based on the stability analysis of the bearingless rotor model test-bed and the compatibility design analysis of ground and air resonance of bearingless rotor prototype, some main factors affecting the ground and air resonance were summarized and found. The influence of these design parameters is mainly studied, such as natural frequency, aerodynamic damping, artificial damping, lift force, pitch control line stiffness and flight speed. The influence of these design parameters on the stability was analyzed to provide technical support for avoiding or eliminating the ground and air resonance instability. It provides important design measures for improving or eliminating the ground and air resonance of bearingless rotor.

Lightweight design is an important means to improve the mobility of vehicle-based radar, which runs through the whole process of vehicle-based radar structure design. This paper discusses the lightweight methods involved in the structural design of typical small array vehicle-based radar. Taking a high mobility vehicle-based radar as the specific design object, the integrated design, new light materials, finite element simulation optimization and other measures are used to realize the lightweight design of the radar system. The mobility of radar is improved and meets the design index requirements.

Product market competition intensifies. Designers need logical and easy-to-operate design models to guide product innovation design. Through the technology maturity prediction, demand analysis, system function analysis, problem-solving analysis and preliminary scheme ideality evaluation of the target product, this paper forms an innovative design model of mechanical products based on TRIZ theory. So the product can eliminate harmful effects and deterioration parameters as much as possible in the conceptual design stage. And this model can maximize the evolution trajectory of the technical system and improve the product ideality. Finally, the model is used to carry out an innovative design of the intelligent wire screen knitting machine to verify the feasibility of the model.

In order to improve the control stability of air compressor for fuel cell, an air compressor control system based on open loop I/F startup and improved sliding mode observer is designed. MPC5744P is the main control chip and INCA software is the upper computer. Aiming at the stability of the control, the startup and switching process of the open loop I/F is studied, and the angular acceleration difference between the d*q* coordinate system and the actual dq coordinate system is analyzed to get the right value range. In this paper, the traditional synovium observer is studied in the middle and high speed stage, and the piecewise composite function is proposed to replace the sign function with the discontinuous origin, which weakens the high frequency chattering. The simulation results show that the improved sliding mode observer control method can effectively improve the operation stability of the air compressor.

With the development of society, the demand and production of bottled beverages such as drinks and beer are increasing day by day, and the requirement for automated packaging efficiency and stability of the products has also increased. The design of the electromechanical integration of the pneumatic control system for automatic bottle capping device is proposed for the demand of the automatic cap pressing process of beverage bottles, and the device consists of water bottle conveying module, water bottle positioning module, cap pressing module, bottle in groups pushing module and PLC electrical control system. The composition principle and process flow, air pressure drive and control system of the automatic cap pressing device are analysed and designed. On this basis, the workflow diagram of the system was designed to give the configuration of the relationship between hardware and PLC ports, and the PLC control system was built based on the process action flow and control requirements, and hardware selection and calculation, control program development and simulation were carried out. By using Solidworks Simulation module to perform finite element analysis on the stress of plastic bottle gland, the stress distribution of the gland is simulated by applying extrusion force on the threaded surface, and the applied gland load can effectively ensure that the bottle is not damaged by the finite element stress analysis, which provides some reference.

To address the serious shortage of automatic classification of grain pile in squat silo, it is critical to design a distributor capable of producing grain pile with uniform porosity distribution and good ventilation effect. The research object in this paper is soybean, and a non-spherical particle model of soybean is reconstructed using the measured physical parameters of soybean particles. Using ventilation uniformity as indicator, a squat silo packing distributor was designed and optimized. Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) coupled calculations were used to investigate the static grain pile ventilation process. The results show that, when compared to CFD, the coupled calculation method can more accurately reflect the flow and heat transfer laws within the actual grain pile. The distributor application can effectively avoid the situation in which the porosity of the grain pile is too large or too small. When the distributor structure is six-arm and the rotation speed is six revolutions per minute (rpm). The grain pile ventilation uniformity and porosity distribution are the best.

The hybrid stereo garage can store both buses and cars, which makes reasonable use of space resources and can effectively solve the parking problem in modern cities. In order to meet the transmission requirements of the access car and ensure the service life of the device, it is necessary to carefully select the relevant parameters of the transmission gear and rack. Due to the large handling quality, the gear and rack meshing is the key equipment to complete the handling of the transverse movement, the use of solidworks software to access the device for modeling, and the gear and rack of the device for strength check, calculate the device in the working condition of the transmission gear and rack stress strain. By comparing the motion characteristics of the pinion and rack meshing under uniform and non-uniform loading conditions, the motion characteristics of the pinion and rack handling device motion characteristics. Provide theoretical basis for the existing gear and rack device in the existing engineering applications.

At present, there are two problems in the filter rod storage and transportation system which product model are YF171 and YF172 widely used in tobacco enterprises. One of the problems is that limited curing capacity leads to limited time, which cannot meet the curing time of filter rods at least two hours and the other is that with the increase of filter rod brand, this method cannot meet the requirement of flexible connection of production management. This paper mainly introduces the efficient and stable filter rod storage and transportation system as well as advanced filter rod loading and unloading technology and equipment in Tobacco enterprises. The principle and characteristics of compartment tray used for filter rod loading and unloading, RFID technology and loading and unloading tray equipment are described which provides some reference for other tobacco factories to introduce this set of process and equipment.

Automotive seat adjuster bracket is one of the key components of the automotive seat angle adjuster. The formability of the adjuster bracket directly affects the function of the seat adjuster and the comfort of the seat. In view of the low efficiency of Wire Electrical Discharge Machining (WEDM) and the poor position accuracy caused by a large number of simple dies in stamping forming, a set of multi-position progressive dies is selected to form the adjuster bracket with high efficiency and high precision. It mainly completes the determination of the process scheme, the simulation of formability of the adjuster bracket by Autoform 7.0, the calculation of punching pressure, the layout design and a set of eight-station progressive die designs. This design bears certain guiding significance for the forming of the same type of products.

The continuous innovation of machinery manufacturing technology is machinery: the technical basis and power of industrial development. With the rapid development of China's economy and technology, it has also promoted the development of China's informatization to a certain extent. In the process of development, all fields need to improve work efficiency through advanced computer technology. In order to better meet the needs of China's social development, we must constantly change the original form of economic development, update the original development concept, increase the innovation of mechanical design and manufacturing industry, so that it can better meet the needs of social development and improve its progressiveness level.

The tower crane cab has been seeking the most optimal product design solution. This study adopts the parallel computeraided industrial design method of exterior and interior, and systematically sorts out the correlation between the design elements from three aspects: function, cab form and ergonomics. The driver's behavior is divided into work behavior and life behavior, and the driver's psychological needs are considered in the cab form design. Based on the analysis of industrial design features of tower crane cab, this paper establishes the process framework of computer-aided crane cab industrial design using ergonomic database and tools, and complete a number of optimization solutions to the current problems related to the tower crane cab. Ergonomics software is used to verify the reasonableness of human-machine factors in three aspects: driver visibility, driver working posture comfort, and driver resting space comfort. Combined with the virtual design software to demonstrate the existing solutions, the satisfaction evaluation of the cab design solution was investigated using the scale score. Through the use of computer-aided industrial design technology in the design of the tower crane cab, the elements of the tower crane cab are reasonably divided and optimized, so that its appearance and internal space can be effectively improved. The final design solution enhances the ease of operation, comfort and psychological satisfaction of the driver. It is verified that CAID method is an effective analysis method for tower crane cab design analysis, and the final design also improves the efficiency and comfort of tower crane cab operation.

Aiming at the cracking of support frame caused by vibration of automatic binding device, the vibration characteristics of the device were studied by means of vibration test and modal analysis, and the structure of the device was optimized. Firstly, modal simulation analysis was used to solve the first six-order natural frequencies and the corresponding mode shapes of the device. On this basis, vibration test was completed. By analyzing the acceleration spectrum of four measuring points of the device, the relationship between vibration characteristics and natural frequencies was studied. Finally, choose multi-target optimization method to optimize the device frame structure.The results show that the vibration amplitudes of the measuring points from high to low are as follows: the upper left frame of the device, the beam of the motor, the upper part of the middle frame and the middle of the middle frame. By comparing the mode shapes with the vibration tests, it is found that the mode that has a great influence on the vibration of the device occurs in the second-order, which is manifested as bending vibration, and the device resonates at 9.02Hz. The first and second-order frequencies after the optimization of the bundle device are 5.60Hz and 12.58Hz. Compared with the optimization before,the frequencies increase -10.4% and +39.5%, it has greatly improved the safe operating range of the bundle device.

Most of the new generation aero engines are designed to operate at high pressure to obtain higher thermodynamic efficiency, and the demand for the study of combustion processes in high pressure environment has promoted the development of combustion diagnostic technology. As a fast and non-invasive measurement technique, TDLAS has been widely used in combustion diagnostics in recent years. At present, the research of combustion diagnosis based on TDLAS is mainly carried out in atmospheric pressure environment. In order to study TDLAS combustion diagnosis technology in high pressure combustion environment, there is an urgent need to provide a laboratory high pressure combustion device. To address this problem, a set of positive-pressure combustion flame furnace system was designed independently with high-precision control. The system is mainly based on the high-performance STM32 embedded system and McKenna flat-flame burner. Through fuel injection control and pressure control etc, the system realizes continuous control of fuel flow rate from 8 L/min to 30 L/min and pressure between 0.1 MPa and 0.7 MPa. The stability and accuracy have been improved prominently compared with other studies. In addition, the high-pressure combustion flame furnace also has automatic ignition control and overpressure protection control functions, which greatly improves the usability and safety of the laboratory high-pressure flame furnace and provides technical support for the development of TDLAS high-pressure combustion diagnostic research.

In this paper, the structure and basic working principle of acoustic releaser are introduced. The main structure of the acoustic release is designed, including material selection, pressure shell design, release mechanism design, etc., and the stability check and finite element simulation analysis are carried out. Effectively improve the stability and reliability of acoustic release. It is of great significance to improve the acoustic releaser technology level, meet the needs of Marine investigation and promote the development of marine monitoring technology in our country.

A fully automatic measuring device for solid materials of automatic gravimetric filling instrument is designed. The overall design idea is given. The working principle and process of the device is expounded. Meanwhile, the design schemes of feeding system, conveying system, detection system, unloading system and return system is introduced in detail. The effectiveness and accuracy of the automatic detection realized by the designed device are verified and compared with the traditional manual detection. The results show that the designed device can realize the automatic detection of the dynamic metering performance of the automatic gravimetric filling instrument. The maximum relative error of loading quality obtained by automatic detection and manual detection is only 0.02%. The designed device has the advantages of high detection efficiency, accurate and reliable detection results and strong universality.

Traditionally, the internal of aircraft wings is generally straight spars and ribs. The use of curvilinear spars and ribs (SpaRibs) on the wing can greatly broadens the design space and further improve the aeroelastic performance. An aeroelastic comprehensive optimization design method is proposed for flying-wing aircraft with SpaRibs based on genetic algorithm. The supersonic double lattice method is used to calculate the unsteady aerodynamics, and the modal method is used to carry out the static aeroelastic analysis The flutter velocity is optimized by considering the static aerodynamic deformation constraint. A comprehensive optimization design calculation example of a flying wing aircraft shows that the flutter velocity can be increased by 20.34% on the basis of a weight increase of 1.321% for a wing with a SpaRibs structure. It provides a new idea for the system design of the flying wing aircraft structure and project a fast and effective aeroelastic comprehensive optimization design method.

With the continuous improvement of the functional performance demand of complex electronic equipment, the electronics on board are becoming more and more integrated. Traditional structure designs are becoming increasingly difficult to meet the requirements with harsh weight index. In this paper, a lightweight space-borne electronic device with blind insertion structure is designed. The conventional chassis frame structure is abandoned. By connecting to the backplane through blind connectors, the type and number of cable connections inside the electronic equipment are greatly reduced. It solves the main contradiction of equipment volume, weight and heat dissipation. The mechanical characteristics and thermal analysis of electronic equipment structure are carried out by finite element method. The corresponding structural deformation and stress distributions are obtained. The results show that, the electronic equipment meets the requirements of structural stiffness and thermal design. The structural design is reliable and safe.

In recent years, the rapid development of artificial intelligence technology, operating robots in industrial production applications are becoming more and more widespread, mechanical gripping jaw is an important part of the operating robot, the operation effect is directly related to the operating robot can complete various production operations. This paper introduces the design of robot gripping jaws for grasping special workpieces. By analyzing and summarizing the functional requirements and system components of robot gripping jaws, the main points of gripping jaw design are proposed, and a new mechanical gripping jaw structure is designed. The simulation results show that the designed mechanical gripper meets the requirements for safe gripping of special workpieces.

The effect of percent thickness reduction, feed rate and heat treatment on the forming process of 2A12 aluminum alloy thin-walled shell was studied. The experimental results show that the blank in H112 state was annealed at 380℃×1.5 h, followed by multiple passes spinning, followed by 330℃ × 0.5 h stress relief annealing in the intermediate process, and finally by vacuum air cooling at 495℃×40min. The ellipticity of workpiece can be controlled within 0.12 mm, the tensile strength reaches 490 ~ 517 MPa, and the elongation reaches 13.0~15.5%.

At present, the traditional heavy-duty diesel engine main rotor and core shaft docking process solution has low precision, backwards supporting equipment, poor stability and other problems. In this paper, several solutions are proposed to address these problems, and two new designs are finally identified. Option A is to improve the accuracy of the main rotor-core shaft alignment by changing the placement of the rotor and core shaft, using telescopic hydraulic cylinders and adopting fixtures to fix them; option B uses 3D laser scanning technology, high-precision truss manipulators and "trap" type structural fixtures to solve the problem of inaccurate alignment between the keyway in the rotor cavity and the core shaft key and the inaccurate alignment between the rotor and the core shaft key. We also used 3D modelling and animation to solve the problems of the rotor core and core shaft shaking when the platform moves. We also simulated the working process of the two solutions through 3D modelling and animation. After comparison and analysis, both solutions can effectively achieve the automatic alignment of the rotor core and the core shaft key, ensure the coaxially of the rotor and the core shaft, and reduce the offset.

In terms of optical requirements and launch costs, large-diameter mirror should not only ensure fine surface accuracy, but also pursue high the rate of lightweight. Starting with material selection and shape design, the structure design of the 2 m mirror of a space remote sensor is carried out, and the preliminary mirror body is obtained. Then, combined with a platform of design optimization called Isight that integrated modeling software, finite element analysis software, data processing and analysis software, we optimized the key structural parameters of the mirror in detail, obtained a SiC mirror with the mass of 178 kg, its the rate of lightweight was as high as 90.9% and the RMS of surface shape accuracy under gravity deformation is 2.2 nm. On this basis, we designed and simulated the flexible support and other mirror components. The results indicated that the first-order natural frequency of the mirror components was 113.8 Hz, the RMS of surface shape accuracy was 8.1 nm under gravity deformation when the optical axis is horizontal, and 8.2 nm under the condition of 2°C temperature change, which were better than λ/60, could meet the requirement of the design index completely.

For large and complex structures with repetitive characteristics, a multi-stage substructure dynamic analysis method based on modal synthesis is proposed to effectively improve the efficiency of simulation calculation. First, the repetitive components are taken as the primary substructure, and the components that produce local modes in the primary substructure are taken as the secondary substructure. The modal synthesis method is used to truncate all modal characteristics of the secondary substructure, and the constrained modal parameters and main modal parameters of the primary substructure are obtained. Then, according to the spatial coordinates, the primary substructure stiffness matrix and mass matrix are repeatedly assembled to obtain the condensation model of the whole structure. The condensation model is used for dynamic simulation to obtain the acceleration load of the substructure installation interface. Finally, the internal dynamic response of the substructure at all levels is obtained by using the super-element method. The simulation analysis of space-borne phased array synthetic aperture radar antenna shows that the multi-stage substructure dynamic simulation analysis results are highly consistent with the traditional analysis results, and the calculation efficiency is increased by more than four times. The substructure dynamic analysis method is reasonable and reliable.

Magnetorheological (MR) damper can adjust the damping force of the damper by changing the viscosity of Magnetorheological Fluid (MRF). Because the total damping force of MR damper includes viscous damping force and shear damping force, the shear damping force is related to the magnetorheological effect of MRF, and it is difficult to determine its value, which is not conducive to the forward design of MR damper. Aiming at the above problems, the maximum shear damping force of MR damper is predicted by combining the shear damping force formula of damper, electromagnetic simulation, MRF characteristics and damper damping channel parameters, and is verified by the dynamometer test.

In order to effectively solve the problem of low efficiency of roadway road surface leveling, combining with the analysis of roadway road surface leveling demand and utilizing the operation advantages of multi-functional vehicles, a kind of underground coal mine vehicle-mounted flat roadway device is designed. The device can be used with multi-function vehicle to quickly realize the soil loosening and leveling of the road surface, saving a lot of labor and equipment procurement costs. The structure, working mode and main characteristics of the structure are analyzed. The practicability and reliability of the device are further verified by using the device.

Aiming at the integration, transmission and sharing of multi-source heterogeneous data in the production process of textile machinery manufacturing enterprises, and combining with the actual production of enterprises, an enterprise-oriented business process model is built, a workshop manufacturing process data management model is established, and the production data is preprocessed such as anomaly correction, time registration, timing data complement, etc., and the ontology-based heterogeneous data integration method is adopted, realized the data integration and sharing of intelligent production in textile machinery manufacturing workshop, and provided data support for digital twin platform and simulation optimization decision; the digital workshop data integration management system is designed and developed. Through the integration of SAP, SCADA and other system data, the production progress tracking, equipment operation monitoring and production-related data statistical analysis are realized, and three-dimensional visualization is carried out in combination with three-dimensional models to meet the data management requirements of the workshop.

After more than 20 years of development, metamaterials have gradually become an important subject in new material technology since their birth in the early century. As an important part of modern metamaterials, materials with negative Poisson's ratio have been applied in aerospace, military industry, medical and health care, satellite, automobile, ship, transportation and packaging and other fields ^[1-5]. In this paper, a three-dimensional negative Poisson's ratio structure is designed, and the influence of its structural parameters on mechanical properties is studied through theoretical calculation and simulation. The negative Poisson's ratio performance of three-dimensional negative Poisson's ratio structure in multiple directions makes it promising to be applied in a variety of occasions.

Axial flux motor has the advantages of short axial size, flat and compact structure, high efficiency and power density, and has a very broad application prospect in electric vehicle drive, wind power generation and other fields. In this paper, a drive motor for electric vehicles with a power of 25 kW, rated voltage of 200 V and rated speed of 3000 rpm is designed by using the yokeless and segmented armature (YASA) disk structure. Some size formulas are given, and its output characteristics are analyzed. And then, the cogging torque is reduced by the method of the permanent magnet skewing pole and the stator shoe shifting. Finally, the finite element 3-D model and calculation are built by ANSYS. The results show that the electromagnetic scheme design is reasonable, and also verify the availability of the permanent magnet skewing pole and the stator shoe shifting to suppress the cogging torque, which has reference significance for the research of YASA motor.

The energy-storage aircraft ground air conditioning system can use the energy-storage system to realize cold storage or heat storage at night, and the direct compression refrigeration system can be used for combined cooling or heating during the day. The storage and discharge capacity of the energy storage device directly affects the operation performance of the ground air conditioning system of the entire energy storage aircraft. The storage and discharge capacity of the energy storage device is closely related to its volume, structure and characteristics of the refrigerant storage process. Based on the design requirements of the energy storage aircraft ground air conditioning system, the energy storage device is designed, and the energy storage and discharge characteristics of the energy storage device are studied and discussed using numerical simulation method.

This research is based on the ROBOCON requirements of the 21st National College Student Robot Competition, and the design object is R1 robot, also known as mobile strike robot. In this paper, the structure design and modelling of the robot are described in detail, and the design scheme of the three-wheel vector motion chassis is innovatively proposed. The paper details the structural design and modelling of the robot, innovatively proposes a design scheme for a three-wheel vector motion chassis, which has the characteristics of compactness, fast response, and strong adaptability. A simple and efficient mechanical arm clamping mechanism is designed to achieve rapid loading. Combined with finite element analysis, a lightweight and stable three-friction wheel launching scheme is adopted to achieve accurate hitting of the target. And the overall structure is optimized by lightweight design, through physical testing, excellent performance, providing a certain reference for the structural design of similar competitive robots.

By using 3Dmax modeling software to analyze the application of 3D modeling technology in wardrobe design, this paper shows the modeling process of wardrobe design using 3Dmax modeling technology, and introduces the auxiliary role of 3Dmax 3D modeling technology in wardrobe design. Finally, take the wardrobe as the creation template, and set the modeling accuracy requirements of the wardrobe 3D model according to the actual size and 3D model effect of the conventional wardrobe. Under the set accuracy requirements of wardrobe 3D modeling, based on the interior structure of the wardrobe, use the advanced modeling method in 3Dmax modeling software to build the wardrobe 3D model, and combine with 3Dmax modeling software to show that the computer 3D modeling technology can improve the work efficiency of the wardrobe design.

The measurement of torque and angle is widely used in industrial mechanical arms and wheeled robots. The split torque sensor and rotary encoder have the disadvantages of high installation difficulty, complex wiring, large joint volume and high cost. A new type torque/angle multi-function sensor was presented in this paper. The mechanical structure of the torque sensor cross waist hole elastomer and hollow shaft angle sensor was designed. The structural parameters of the sensor were optimized by the workbench finite element technology. The hardware circuit and software algorithm of the composite sensor were carried out. The experimental calibration system of the composite sensor was built. The experiment demonstrates that the sensitivity of torque measurement is 0.102 (V/(N·m)), the linearity is 2.12% FS, the repeatability error is 0.61% FS and the hysteresis is 0.94% FS. The angle measurement error is ± 0.05°. The measurement accuracy meets the needs of industrial applications and has the advantages of small size, convenient use and high cost performance.

Since traditional fused deposition 3D printers have problems such as low printing efficiency and easy breakage of silk, multi-material 3D printing technology based on screw extrusion principle can effectively solve such problems. Therefore, this paper takes the multi-material 3D printer based on the principle of screw extrusion as the research object, designs, models and builds its structure, and adopts the research method combining finite element simulation analysis and experimental verification to verify that the designed multi-material 3D printer can realize multi-material 3D printing, which has important theoretical guiding value and practical reference significance for engineering applications.

Rather than open-air planting, small and medium-sized farm facilities dominate agricultural production in China. The dimensional characteristics of these facilities include a low ceiling height and a narrow width. With these dimensional parameters, field agricultural robotics could be improved in these facilities, leading to hand transplanting by farmers. To meet the demands of small and medium-sized agrarian facilities for sapling transplantation, a sapling planting robot has been developed whose functions are to plant saplings semi automatically to meet the needs of these facilities. All mechanisms were driven by electric power due to environmental sustainability. Throughout this paper, the main focus will be on the design of the mechanical system used. Hardware components of this machine include the chassis, sapling feeding unit, transmission system, and duckbill planter. This machine's hardware design has been completed, along with the design of its central control system using a PLC (programmable logic controller). The sapling planting robots were tested at 10 m/s with the highest success rate measured at 96.25%, respectively. In conclusion, the machine is capable of planting well and has an effective control system.

The problem of oil leakage of gearbox housing of a certain model is studied. Through the detailed fault tree analysis of various influencing factors. According to FTA analysis results, the optimal scheme is selected. The contact area of the box surface and the tightening torque of bolts were optimized. It improves the quality of the vehicle and provides reference for solving similar problems in the later period.

In order to solve the problems of winches in fully mechanized coal mining face used to do the roadway supports withdrawal work, such as the difficult operation, the tedious positioning, the inefficiency, the frequent pull-off and rope breakage and so on. A new dual-speed multi-purpose withdrawal winch with variable frequency speed control and self-supporting positioning system is proposed in this paper. Firstly, The shape and performance boundary parameters of the new winch are obtained by analyzing and investigating the existing winches and the requirements of the new. Secondly, the transmission system is designed including the calculation of drum, the development of variable frequency motor with low speed and high torque and the design and arrangement of reducer. Then the overall structure of the new dual-speed multi-purpose winch is designed by combining the researches mentioned above and the development of the optional support device. Finally, from the application effect of the new winch, the design scheme of overall structure is reasonable, reliable and fully meets the actual demands.

Agricultural machinery and equipment is an important basis for the vigorous development of China's modern agricultural economy, but also to deepen the important driving force of agricultural technology reform. In the rapid development of science and technology and national policy support, China's agricultural machinery manufacturing enterprise development by leaps and bounds, but there are still some problems. In order to solve the problems in the production process of agricultural machinery, a production process optimization model based on the extension theory is constructed. Take the core products of agricultural machinery manufacturing workshop as an example, the 'bottleneck' problems such as unbalanced production line, accumulation of work-in-process, idle resources and long die change time are found by using Flexsim simulation technology. The problem is determined quantitatively by using the extension primitive theory to establish the compatibility correlation function, and the expanded analysis is used to establish the relevant network and find the solution. And combined with extension transformation analysis and lean production theory to improve, generate a variety of optimization strategies, according to the actual needs of enterprises to filter the optimal solution. The final simulation verifies the feasibility of the solution. After the optimization, the balance rate of the production line is greatly improved, the number of work-in-process is significantly reduced, and the personnel and equipment are efficiently utilized.

Gas bearings are indispensable equipment in the field of hydrogen liquefaction, which has the characteristics of high life and stable operation. While gas suspension bearings are mainly divided into radial bearings and thrust bearings, this paper focuses on the introduction of thrust bearings, proposes a set of structural parameters of bearings and carries out engineering calculation and simulation calculation of characteristics.

In winter, the elevator shaft of super high-rise buildings causes a significant chimney effect. The elevator door cannot be closed normally, which severely affects the regular operation of the building. In this study, the computational fluid dynamics method was used to simulate outdoor air conditioning, analyze the effects of an opening area of 1 m² and different opening distances on the elevator shaft, and simulate the cooling effect of air mechanically fed at volume rates of 3600–10800 m³/h. The results showed that the combined natural and mechanical ventilation transmitted cold outdoor air with the most significant effect. The relationship between the theoretical thermal pressure and the pressure difference between the two sides of the elevator door was established and combined with actual measurements of the pressure difference between both door sides at different outdoor temperatures. The effects of different measures on the pressure difference between the two sides of the elevator door were analyzed.

The current method of detecting ink layer thickness still has the disadvantages of slow speed, will produce wear and tear on the detection object, low accuracy, etc. For this reason, this paper proposes an optimized Hough algorithm detection method for the existing ink layer thickness detection method. Firstly, based on the triangular laser principle, the measurement image is captured by CMOS camera; secondly, the probabilistic Hough linear transformation algorithm based on vertical straight line is optimized; finally, the system calibration and accuracy measurement are completed. The maximum detection thickness of the algorithm optimization reaches 20 µm, and the detection accuracy is better than 3 µm, which verifies the feasibility of the algorithm optimization

Drag reduction of automobile vehicle has a great significance for energy saving and ecological protection. A novel wake structural truncated-pyramid shape spoiler is proposed in the paper to reduce aerodynamic drag induced by rear base, and the simplified Ahmed’s model is established based on COMSOL RANS k-ε turbulent flow module, and the modeling approach yields good agreement with the former experimental and simulation results. The effect of spoiler geometry parameters on velocity distribution and drag coefficient under typical wind speed is also analysed through the modeling. The results indicate that drag coefficient can be reduced up to 38.27% through installing the truncated-pyramid spoiler, and the drag coefficient roughly decreases with the increasing of truncated-pyramid height and the decreasing of truncated-pyramid shrinkage. The research would provide a new way for mobile vehicles with bluff wake body to improve the aerodynamic performance.

The finite element analysis method is used to simulate the mechanical behavior of packer rubber based on the virtual work principle, the Von Mises yield principle, and the contact nonlinear theory. The influences of working temperature, intermediate rubber hardness, and casing wall thickness on the sealing performance of packers were analyzed, and the contact stress distribution law between combined rubber and the casing wall under different conditions was obtained. The results show that: (1) as the temperature rises, the sealing performance of rubber tubes rises nonlinearly; (2) as the hardness of the intermediate rubber decreases, the sealing performance of the split rubber gradually increases, and the sealing performance is improved. (3) With the increase in casing wall thickness, the maximum contact stress between rubber tube and casing increases, and the sealing performance is improved.

The mechanical microenvironment of the callus plays an important role in fracture healing. Many literatures have studied the influence of parameters in the mechanical microenvironment (such as fixator configuration, loading, etc.) on fracture healing. Few of them consider the influence from the direction of interfragmentary movement (IFM). In this study, combining the characteristics of a new type of external fixator, a genetic algorithm-based method for adjusting the IFM direction for fracture healing is proposed. In this method, the Mechano‐regulatory theory is used to simulate the fracture healing process, with the goal of improving the axial stiffness of the callus, and the optimal IFM direction is then found by utilizing genetic algorithm. The results show that the IFM orientation obtained by the proposed method can increase the axial stiffness of the callus faster. Moreover, it means that the weight-bearing capacity of the tibia can be quickly restored, and the external fixator can be removed as soon as possible, which provides a reference for solving the delayed and non-union problems of oblique fractures.

During the operation of the centrifugal pump, the impeller is easily resonated by multi-frequency fluid excitation, so it is necessary to perform modal analysis on the impeller to ensure the safe operation of the unit. In this paper, taking a certain type of centrifugal pump impeller as the research object, the dry and wet modal characteristics of the impeller are studied by acoustic fluid-structure interaction method, and the effects of the number of splitter blades and circumferential position of the splitter blades in the duplicated sector on the natural frequency are analyzed. The results show that the natural frequency of the impeller decreases significantly compared with the natural frequency in air due to the added mass effect of the fluid. Adding splitter blades between the main blades of the impeller will reduce the natural frequency of the impeller in air and water, and the frequency drop rate and added mass coefficient will decrease; the position of the splitter blades in the circumferential direction of the impeller has little effect on the natural frequency of the impeller.

In this paper, computational fluid dynamics (CFD) was used to numerically simulate four ventilation modes of ISO class six clean room, to explore the effects of different FFU-clean bench coverage rates on the temperature and humidity in the clean room, and to establish a hierarchical analysis (AHP) entropy weight evaluation system to determine the best coverage rate (C). The results show that the temperature difference, relative humidity difference and airflow velocity difference increase with the increase of coverage rate; when the coverage rate C=25%, the thermal comfort and cleanliness of employees are satisfied with priority; when the coverage rate C=50%, the high energy efficiency of the ventilation system is achieved.

The weight reduction of UAVs can reduce power consumption, improve the carrying capacity and range, and is of great significance to the green development of the civil aviation industry. Based on the topology optimization theory, the finite element analysis and lightweight design of the UAV fuselage are carried out. Through the optimization and comparison of five schemes, i.e., symmetry, bidirectional draft, unidirectional draft, bidirectional draft+symmetry and squeeze, the comparison results show that the symmetrical optimization is the best scheme. After the optimization of the UAV fuselage model, the mass reduction ratio is 50.24%, the maximum Mises equivalent stress of the model under the load condition is 10.82 Mp, the maximum displacement is 0.7512 mm, and the minimum safety factor is 4.2, which meets the strength and lightweight design requirements of the parts, and provides a new idea and feasible scheme for the lightweight design of the UAV.

The advantages of biaxial polypropylene (BOPP) film make it very valuable to use, but the bottleneck of its production line hinders the development of its production capacity. In this paper, based on the plant simulation computer simulation platform, taking BOPP production line as a case study, the identification and solution of production bottleneck of serial production line are studied. The results show that the production bottleneck exists in the film production line, and the three optimization schemes can alleviate the production bottleneck to a certain extent. The feasibility of some optimization and bottleneck identification methods and computer simulation methods are verified.

With the continuous turmoil in the traditional energy market and the serious environmental problems caused by the overuse of fossil fuels, it is urgent to find sustainable alternative energy sources. Biodiesel has aroused great interest because of its renewability, biodegradability and environmental friendliness, as well as its feasibility and adaptability as an alternative fuel. In this paper, a four-stroke model of the QC490GP diesel engine is established. The accuracy and reliability of the model are analysed and verified by comparing the simulation results with the experimental data. The free regulation of mixed fuel components is realized by establishing a biodiesel model, and the variation curves of power, torque, brake specific fuel consumption (BSFC) and NOx emissions are obtained. The results show that power and torque increase with the increase of biodiesel blending ratio, and BSFC decreased with the increase of biodiesel blending ratio.

The LNG (liquefied natural gas) marine loading arm is an important oil and gas transportation equipment installed at the dock. In order to analyze the impact of the LNG marine loading arm under extreme typhoon weather and provide theoretical guidance for subsequent research and development, a three-dimensional model of the marine loading arm was established using Solidworks software and simulated using Fluent software. The SST K-omega turbulence model was selected, and a velocity inlet was written using UDF and a pressure outlet was selected. The SIMPLE solver was used to solve the model. The flow field model of the LNG marine loading arm was simulated, and it was found through data analysis that the structures with greater force were the rope wheel and the counterweight bracket. This provides a way of thinking for the subsequent optimization design of the LNG marine loading arm.

This paper proposed a detailed three-dimensional finite element model (FEM) for composite mechanical joints and developed a parametric, automatic, and process-based tool for rapid modelling and analysis of such joints. The tool allows for batch modelling and analysis for large configurations, significantly improving simulation efficiency. A signal-bolt, signal-lap composite joint was analysed to demonstrate the effectiveness of this tool. In the simulation, the clearance effect was studied and the reduction in stiffness with the increasing clearance was captured by the model. Based on the neat-fit (C1), the overall stiffness of the C2, C3 and C4 configurations obtained by simulation in this paper are reduced by 1.68%, 3.86% and 9.23% respectively. While the stiffness reduction measured by experiments are 1.90%, 7.30%, and 10.4%, respectively.

Based on the structure of a certain large-scale centrifuge and its chamber, a hydrodynamic lattice model is established to study the wind field inside the centrifuge chamber. The flow field in the centrifuge chamber was numerically analyzed through LBM method, and the wind speed and pressure distribution parameters during the transient acceleration phase and the steady-state phase were obtained. The relationship between the wind speed and pressure and the rotational speed of the centrifuge was studied by changing the rotational speed and the corresponding effective g value.

According to the requirements of structural vibration test standard of shipborne electronic equipment, the finite element model of the electronic display console was established by ANSYS, and the modal frequency, sine sweep vibration response, bumping response and shock response of the display console were obtained. According to the calculation results, the strength of the console is checked and the mechanical reliability of the console is analyzed. The results show that the stresses near the mounting holes of the electronic console shock absorber are relatively high, but they are all lower than the maximum allowable stress of the console, and the console can work reliably under various test conditions. The modeling and analysis method presented in this paper can provide a good reference for the mechanical analysis of similar electronic equipment.

In this study, the discrete element method (DEM) and experimental means are proposed to be used, combined with theoretical mechanics, powder mechanics, fluid mechanics, mechanical vibration and other mechanical theories. When studying the multi-factor and multi-curve superimposed vibration of multi-component mixed particles, the structure of vibrating body, vibration combination order, vibration time, vibration frequency, amplitude, particle factors and other factors affect the dynamic parameters, kinematic parameters, particle layer flow field, organization field and other laws of the separation process of multi-component mixed particles. Reveal the evolution mechanism of the breeding, growth, formation and decay of the separation configuration of multicomponent mixed particles, and carry out SPSS multivariate statistics and regression analysis to establish the corresponding mathematical model. On the basis of the above, a multifactor and multi-curve superposition vibration separation experiment was carried out on the mixed particles of metal ore, and the separation process was effectively controlled by using MATLAB neural network tool. Finally, it is proposed to use the bionic method to observe the manually superimposed vibration modes such as round screen and dustpan, and use the bionic hand and bionic joint to design the mechanical and electrical drawings, action flow diagrams and specific procedures of the equipment, and manufacture the corresponding vibration equipment. The work will enrich the theory of vibration separation of mixed particles, and provide useful theoretical reference and practical equipment for the vibration separation process of multi-component mixed particles with different shapes, sizes and densities.

Camera imaging quality is of great importance to aerial photography and space photography, especially in the field of military reconnaissance and telemetry of geographic resources. During the flight of the airborne camera, the image motion is caused by factors such as the flight speed and flight attitude of the aircraft, which will greatly reduce the image resolution and seriously affect the imaging quality of the camera. In this paper, it is analyzed that various factors of produce image motion in the imaging process of airborne camera, the imaging coordinate system of airborne camera is established, the mathematical model of image motion is established by using the homogeneous coordinate transformation method, and the function relation between the compensation angle of two-axes of the fast-steering mirror (FSM) and the image motion is obtained at last. By establishing a simulation model, the influence of aircraft flight attitude on the imaging quality of the camera is analyzed, which provides a basis for the image motion compensation strategy of airborne camera.

In this paper, the theory and analysis methods of computational fluid dynamics, transient dynamics and other aspects are integrated, and FLUENT finite element simulation software is used to simulate the shock wave signal in two different environments, namely, plain and plateau. The transient dynamic response results under the action of shock wave are obtained through numerical simulation, which provides an effective reference scheme for the operator's protective measures, and provides a reliable theoretical basis for the placement of surrounding equipment and the selection of environment, and reduces the additional damage caused by the experiment.

Facing the significant demand for energy saving and emission reduction in the internal combustion engine industry, a new continuous variable valve mechanism (CVVM) is designed for marine medium and high-speed internal combustion engines. By building a single-degree-of-freedom mathematical model, the influence of eccentric shaft position, eccentricity, and input rocker arm ratio on the variable characteristics of the mechanical motion is studied. The results show that the single-degree-of-freedom mathematical model is accurate and can be used to research mechanism motion variability. Under different vital structural parameters, the mechanism exhibits four variable motion modes with the adjustment of the phase of the eccentric wheel. For the continuously variable Miller mode, when the input rocker arm of the mechanism is constant, and the initial position is the same, the valve motion interference phenomenon is more serious when the eccentric shaft position is farther away from the camshaft, the eccentricity is more extensive, and the input rocker arm ratio is larger. The maximum lift of the valve is unchanged under the influence of eccentricity, and the larger the input rocker ratio, the greater the maximum lift of the valve.

The performance curves are crucial to the safety operation of the compressor. As a method to obtain the performance curves of centrifugal compressor, Computational Fluid Dynamics (CFD has the advantages of high data accuracy, but its calculation cost is expensive. In order to reduce the calculation cost, surrogate model has been widely used to predict the performance curve of the centrifugal compressor in recent years. In previous studies, PR and EFF at various speed lines were predicted separately neglecting the similarities across speed lines. Considering the correlation between different speeds, the multi-task Gaussian Process (MTGP) method was adopted in this paper to predict the performances curves of a centrifugal compressor in a more efficient manner than the conventional models by leveraging the cross-line information. To validate the effectiveness of the method, the predictions from MTGP are compared with that of multi-fidelity method CoKriging and single-fidelity Kriging. Finally, we found that MTGP has the highest prediction accuracy under the same data cost.

Perovskite solar cells (PSCs) have gained momentum in the photovoltaic field because of its high-power conversion efficiency (PCE) and low-cost manufacturing process. In the screening of perovskite materials, CsPbI₃ has attracted widespread due to its good thermal stability, high degradation resistance and excellent photovoltaic performance. However, CsPbI₃'s high band gap (1.73 eV) limits its development in single-junction PSC. In this study, we constructed a double absorption layer CsPbI₃/CsGeI₃ PSC with SCAPS-1D (solar cell capacitance simulator). Compared with the conventional single-layer structure of CsPbI3 PSC, the double-layer CsPbI₃/CsGeI₃ PSC has a broader absorption spectrum and better photovoltaic performance. We systematically analyzed the thickness and defect density of the absorber layer, and the operating temperature on the cell performance and obtained the optimal parameters. In addition, we selected the best electron transport layer and hole transport layer (ETL/HTL) for the double absorption layer CsPbI₃/CsGeI₃ PSC. Under the optimized conditions, all cell performance parameters improve significantly, and its PCE is as high as 28.92%.

The pump characteristic curve is fitted by discrete test points, which is a curve reflecting the inner connection and change laws of performance parameters such as flow, head, and efficiency of the pump, and its accuracy and reliability have a significant influence on its selection and use. This paper designs a cubic B-spline interpolation algorithm, and then conducts a comparative study of the interpolation algorithm and the least squares polynomial fitting method of different orders through experiments and Python programming. The experimental results show that the cubic B-spline interpolation method not only can more accurately describe the variation of the pump characteristic curve under both small and large flow conditions, but also avoid the phenomenon that the curve is not smooth enough and the data does not fit when the least squares method is used to fit the curve, which is of high application value in scientific research and engineering applications.

Reliability evaluation is a fundamental problem to be solved in power system planning and operation, which is of great significance to ensure power supply and provide support for security warning of the power grid. A reliability evaluation method for transmission grid based on risk theory is proposed in this paper, which effectively combines the fault occurrence probability and the result of load loss due to the contingencies, quantitatively describes the reliability evaluation index under different contingencies. This method can provide a comprehensive total reliability evaluation index of the system under different line fault probabilities, which cam reflect the relative reliability of the transmission grid network. Finally, simulation tests are conducted in the IEEE-24 bus system and the effectiveness of the proposed method is verified.

Operational stability is one of the mostcrucial characteristics of bearings in space actuators. Space bearings embrace unique dynamic properties due to their micro-oil lubrication and non-metallic cage. A dynamic simulation of three different B7005C bearing types, a typical aerospace bearing, was carried out in this paper. Steel ball bearings, hybrid ceramic ball bearings, and full ceramic ball bearings were the materials used to make such bearings. The findings demonstrate that, in comparison to steel bearings, the ceramic ball bearings operated stably under heavy radial loads, and that the use of ceramic balls and raceways will reduce the axial inner race deflection and its fluctuation.

In agricultural transport vehicles, the frame has to carry loads from multiple and complex parties, so there are strict process requirements for the frame. In this paper, finite element static analysis of the frame under modal and full load bending conditions is carried out using ABAQUS and SolidWorks software to study the frame strength performance and provide theoretical basis for the optimization of the frame structure of agricultural vehicles.

Aiming at the problem that the pre-tightening force of the bolt is not equal to the set tension value due to the rebound error of the fastening bolt of the hydraulic tensioner, take the M20 bolt of a certain type of press as an example. Firstly, the three-dimensional models of bolts and hydraulic tensioners were established, and a new thread hexahedron mesh drawing method was adopted. Then, the mathematical model of bolt rebound and preload is constructed. Then, the finite element software ABAQUS was used to conduct static analysis of the process of tightening bolts by the tensioner, simulating the residual preload of bolts under 12 groups of different working conditions. Finally, the hydraulic tension experiment was designed for verification. The results show that when the same tension is applied, the residual preload of the bolt is about 65% of the set tension value, that is, the rebound error of the bolt is about 35%, and the error is reduced by 5% compared with the theoretical calculation value, the reliability of fastening bolts of hydraulic tensioner is improved.

As an important part of the aircraft, the analysis of its dynamic performance is also extremely critical. As the core component of the aircraft, the performance of the aircraft chassis plays a vital role in the overall aircraft structure and flight safety. In order to provide scientific basis for the performance evaluation and design improvement of the aircraft chassis, this paper analyzes its dynamic performance and uses 3D simulation technology to carry out experiments on it. This paper mainly uses the experimental method and the investigation method to analyze the relevant data of the aircraft case. The experimental results show that due to the damping of the system, from 2 ms to 4 ms, when the equivalent voltage oscillates, the acceleration pulse remains at 0 value, and the amplitude decreases gradually with time, showing an attenuation trend.

Aiming at the problem that the local deformation of a ring thin-walled part is too large during machining, an improved particle swarm optimization method for milling parameters is proposed. The finite element software is used to simulate the area with large local deformation, and the simulated milling force is obtained. The objective function between machining parameters and milling force is established by orthogonal experimental response surface method. The improved particle swarm optimization algorithm is used to optimize the objective function. Finally, the optimized machining parameters are compared with the empirical machining parameters. The experimental results show that the improved particle swarm optimization algorithm can reduce the milling force in the area with large local deformation by 24.9% and effectively reduce the deformation of the annular thin-walled parts, providing a new reference scheme for technicians when selecting the milling parameters of the annular thin-walled parts.

In this paper, the CFD calculation method is used to calculate and analyze the cavitation characteristics of a pod propeller blade based on Schner-Sauer cavitation model, and the thrust coefficient, moment coefficient, efficiency, blade surface pressure and gas phase distribution characteristics of the propeller under different cavitation numbers are obtained. The results show that the thrust coefficient, torque coefficient and efficiency of the propeller are basically unchanged when the cavitation number is above 1.52, and the cavitation number is reduced to 1.16, and the propeller thrust coefficient changes little, However, the torque coefficient increases slightly, the efficiency decreases slightly, the cavitation number decreases to less than 0.46, the cavitation area covers the entire blade back surface, the area of the cavitation area on the blade surface and the right side of the cabin surface increases significantly, the propeller thrust, torque and efficiency drop sharply, and the propeller is in full cavitation state.

The analysis of product image modeling is the premise of designing new style modeling. This paper proposes a modeling and analysis method of product image modeling based on multi-objective decision-making. Firstly, the product image modeling design is analyzed, and the modeling method of product image modeling style is proposed based on the non-inferior solution of multi-objective decision-making in terms of maximum and minimum objectives. Then, taking the mining vehicle as the object, using the semantic differential method and image scale method, a questionnaire survey on the safety image of the mining vehicle was carried out, and obtain image scores of 12 mining vehicles were. Finally, the principal component analysis method is applied to build mining vehicles' safety image modeling style model from the two dimensions of safety connotation and artistic conception. The research provides a new way for the cognitive analysis of product image modeling style and enriches the theory and methodology of product image modeling design.

Aiming at the structural vibration problem of a 600 MW steam turbine generator, the model of its rotor and stator is established by using the finite element theory, and their respective structural characteristics are studied. The results show that the reason for the insufficient stiffness of the generator end cover bearing is the deformation on both sides of the generator stator. The vibration fault was solved by the method of weighting on site.

The related parameters of electronically controlled injector have profound influence on the fuel injection performance of injector. However, most of the current researches focus on some parameters of actuator, but few on some parameters of nozzle. Based on the direct-drive giant magnetostrictive injector, the simulation model of this injector was built with AMEsim simulation software, and the effects of nozzle parameters such as half cone angle of needle valve, diameter of needle valve stem and diameter of nozzle hole on the injection performance of this injector were studied. In view of the many research parameters, the orthogonal experiment method was adopted to design the experimental scheme reasonably, and finally L16 (45) orthogonal experimental table was selected for the experiment. The results show that the parameters that have the greatest and smallest influence on the fuel injection performance of this injector are the cavity parameters and the number of injection holes. The optimum combination of nozzle parameters was obtained, and the fuel injection performance of injectors before and after the optimization of nozzle parameters was compared. It was found that the optimized combination of nozzle parameters had a better correspondence between fuel injection rate and needle valve displacement, which provided the possibility for further improving the flexibility of fuel injection rate.

Taking a pair of gear pairs of an aeroengine gearbox as the research object, the tooth surface equation of the tooth tip modification of the cylindrical gear and the calculation formula of the tooth tip modification amount combined with the finite element method were derived to carry out the modification design of the gear. The thermoelastic coupling finite element model of the gear pair before and after modification was established respectively. Through the stress analysis and comparison, the maximum equivalent stress and contact stress of the gear pair after modification were significantly reduced, which improved the load bearing condition of the gear meshing process, and has certain reference value for the stress optimization of other gear meshing process.

In order to investigate the influence of plasma combustion on the performance of aeroengine combustor, a local geometric model of the two-head sector section of the short combustor was established. The steady-state numerical calculation of the kerosene in the combustor was carried out under the conventional mechanism and the specific operating condition under the plasma mechanism. The numerical calculation results of the combustor with or without the plasma mechanism were compared and analyzed. The results show that the average temperature, flow field velocity, density and turbulent kinetic energy behind the cyclone in the two-head fan section of the combustion chamber are better than those under the conventional mechanism, which indicates that the application of plasma mechanism can significantly improve the combustion performance of the combustion chamber to a certain extent. Under the chemical proper ratio, the average temperature of the outlet section of the combustion chamber increases from 1910 K to 2050 K, and the combustion efficiency increases from 82.4% to 90.1% by 7.7%, indicating that the addition of plasma mechanism can deepen the chemical reaction degree of kerosene and release more heat to improve the combustion efficiency of kerosene.

A hardware-in-the-loop simulation test bench based on FPGA is proposed to efficiently solve the automotive power electronics testing technology. The test bench is composed of a master control system, a real-time simulation platform, an RCP rapid prototype controller, a tested controller and an OPAL-RT solver. The simulation step can reach 1 us. Automated test software can be used to set test conditions and effectively verify the performance of MCU drive and fault protection strategies, demonstrating its effectiveness.

Pendulum tuned mass dampers are widely used in structural vibration reduction because of their convenience in installation, maintenance and replacement, economy and practicality. It suppresses or eliminates the vibration of the main system by tuning the natural vibration frequency of the pendulum to close to the control frequency of the main system, so that the pendulum produces the opposite vibration of the main system. In this paper, through the multi-objective optimization design of the passive damping system with undamped main system and the active damping system with damped time-delay feedback, the equal peak control of the amplitude-frequency response curve of the main system and the effective control of the difference between the formant and the anti-formant are realized. The results show that the oscillating amplitude of the pendulum tuned mass damping system is suppressed in a wide frequency range by equal-peak optimization control with time-delay feedback. By controlling the difference between the resonance peak and the antiresonance peak, the flatness of the amplitude-frequency response curve is guaranteed.

In order to solve the problems of high lower limit and low accuracy of existing flow testing techniques for horizontal well output profiles, a phase-regulated volumetric flow meter was designed and a single-phase flow measurement method was proposed. Firstly, Gambit was used to establish the simulation model of the flowmeter; then the finite element simulation software FLUENT was used to study the dynamic regulation effect of the flowmeter for oil and water two-phase flow under the conditions of different flow rates and water content, which verified the feasibility of the flowmeter; finally, according to the simulation monitoring data, the response value of the array conductivity sensor under the oil and water measurement mode was obtained respectively with the change of liquid level, and finally the single-phase flow rate of oil and water was deduced.

In this paper, the CEL (Coupled Eulerian-Lagrangian) fluid-solid coupling simulation method is adopted to simulate the mechanical behavior and bubble pulsation evolution process of the transformer oil filled in the converter transformer when a high-energy discharge failure occurs in the on-load tap-changer of the converter transformer. The mechanical response of the tap changer and its solid structure is analyzed. Based on this, the compensation performance and strength of the pressure compensated expansion joint installed on the tap changer are evaluated.

The transverse stiffness simulation method of assembled small box girder bridge directly affects the internal force distribution of the structure. However, the lattice model of inclined small box girder bridge is seldom studied. In this paper, three box girder bridges with different diagonal angles of 25 m span are taken as the object, and different transverse stiffness simulation methods are used to calculate the natural vibration frequency of the bridges. The results are compared with the measured results. The results show that the beam end stiffness simulation method is most close to the measured results, and the roof section simulation lateral stiffness is much different from the measured results.

In the heave compensation process of the offshore crane winch, there is time delay in the detection of the heave motion signal of ship, which affects the work efficiency. In order to achieve accurate prediction of ship motion, this paper has carried out research on the prediction algorithm of heave motion based on time series, established an autoregressive model (AR) of heave displacement sequence and carried out multi-step prediction simulation research on it, it is verified that the algorithm has a good prediction effect on the ship heave data. After that, an improved PID control scheme based on the motion prediction algorithm is proposed, and analyzed the influence of different control coefficients on the compensation effect of the system. Then compared the control effect of traditional PID control and the scheme proposed in this article, the effectiveness of the proposed control scheme based on forecasting algorithm is verified.

Sub synchronous vibration problems occurred many times during the development and production of liquid hydrogen (LH₂) turbopump for a certain type liquid hydrogen-oxygen (LOX/LH₂) rocket engine. The results show that nonlinear excitation force at labyrinth seal may be the main reason of sub synchronous vibration. In order to obtain the effect of seal force acting on rotor system, and to provide theoretical support for design and improvement of LH₂ turbopump. In this paper, mathematical model of LH₂ turbopump rotor system and seal fluid force is established, coupled by MATLAB program. Then we realized the rotor system steady and transient state calculation. Results show that a kind of vibration which frequency near the first natural frequency will be induced by labyrinth seal fluid force. Increasing seal clearance can improve the stability and the critical speed margin of LH₂ turbopump rotor system. But it will also increase the amplitude of vibration, and the ratio of displacement to seal clearance, which is harmful to avoid the phenomenon of friction. The relationship between inlet preswirl and stability of rotor system presents obvious nonlinear characteristics, so needs more attention during design and choose the optimal value.

Stripping is the preparation work before the cable lap lead operation, the traditional manual work method is low in efficiency and high in danger. Therefore, this paper designs a lapping and stripping robot, on the basis of which the focus is on the control method of cable stripping. On the one hand, by analysing the peeling mechanism, a mechanical model of peeling is established; on the other hand, Kalman filter and multiple linear regression are used to quantify the state of the motor output torque and achieve precise control of peeling without damaging the aluminium core. Experimental tests show that the proposed method can be applied to a robot instead of manual operation, which can effectively reduce the rate of peeling wire loss and improve the operational efficiency and robot robustness.

In order to solve the sealing problem of the cooling and evaporating medium of the large air volume fan in the large ship equipment, a five-stage, nine-tooth, large-gap magnetic fluid and magnetic grease combined rotary sealing device is designed, which is suitable for the environment with high rolling and high corrosion of large ships. Through the theoretical derivation of the pressure resistance formula and the Ansys finite element analysis, it is found that the pressure resistance of the seal increases with the increase of the saturation magnetization of the magnetic fluid, the yield stress of the magnetic grease and the magnetic field gradient in the seal gap. On the sealing test bench, the sealing pressure test was carried out on the device. When the maximum clearance is 0.7 mm, the single-stage pressure resistance capacity can still reach 20 KPa, and the sealing capacity remains stable with the increase of rotating speed. Theoretical and experimental results show that the design is suitable for large clearance sealing of high-power motors or other high vibration equipment in corrosive environment.

According to the requirements of airworthiness regulations, the safety pin of the flap support arm of a civil aircraft should bear the aerodynamic load of the aircraft wing under normal conditions, and at the same time, it also should be convenient for emergency disconnection to avoid damaging the overall oil tank of the wing and then causing greater accidents under emergency conditions. Therefore, accurate prediction of the fatigue life of the safety pin of the flap of a civil aircraft is of great significance to the operation and maintenance of the aircraft. For the safety pin of the flap support arm, the static tests were carried out first to determine the dangerous position and the ultimate strength of the flap support arm. Then the finite element analysis by Abaqus was carried out to obtain the nominal stress and stress concentration coefficient of the dangerous position. In addition to the prediction of fatigue life of the dangerous position was obtained by using the nominal stress method and the fatigue damage accumulation theory. Finally, the fatigue tests of the safety pin were conducted to verify the results of life prediction. The error between the fatigue test results and the results predicted by the nominal stress method is small, which conforms to the actual needs of the engineering.

Vibration and buffeting are important flight test subjects for civil aircraft airworthiness certification. It is an important task to determine the initial buffeting boundary of the aircraft ac-cording to the flight test results. This paper introduces the time domain analysis method of initial buffeting data and the optimized frequency domain analysis method: including the data preprocessing in the frequency domain analysis, the determination of analysis standard, and the theoretical analysis idea of determining the initial buffeting according to the variation regulation of frequency domain vibration peak with angle of attack; the initial buffeting evaluation standard of subjective evaluation combined with theoretical analysis is proposed; according to the determined initial buffeting standard, the initial buffeting test data of an aircraft are processed, and the initial buffeting boundary is given; finally, a method of extending the 1.3 g buffeting envelope according to the initial buffeting boundary is given.

Aiming at the failure problem of the silver plating layer of the waveguide falling off under the action of thermal stress during the vacuum thermal test of the spacecraft, and the problem that the amplitude consistency requirements of the radio frequency channel of the thermal test are not easy to achieve, the temperature control device filled with composite phase change material is proposed to control the temperature of the waveguide during the vacuum thermal test, and the counter-gravity direction and paragravity direction of this scheme and other two schemes (fins and aluminum blocks) of this scheme are simulated by Thermal Desktop software. According to the simulation results, the advantages, disadvantages and scope of application of each scheme are analyzed and summarized. The paragravity phase change device scheme is adopted for temperature control, and the peak temperature of the waveguide is reduced by nearly 20% compared with that without thermal control treatment.

KR (Kanbara Reactor) method is the mainstream desulfurization method in hot metal pretreatment. The mixing efficiency of three kinds of blades, namely, the regular four-blade propeller, the spiral three-blade propeller and the double-layer regular four-blade propeller, was studied by numerical simulation method. The results showed that the mixing time of the double-layer regular four-blade propeller was 7.3% shorter than that of the regular four-blade propeller, and 38% shorter than that of the spiral three-blade propeller. Through the analysis of the axial velocity distribution in the molten iron, it was found that the axial velocity of the molten iron in the double-layer regular four-blade propeller agitator was larger.

The 3D cutting simulation of Ti6Al4V titanium alloy material by trapezoidal chip breaking groove tool with different land width was carried out by ABAQUS, and the cutting force in three directions were obtained. MATLAB software was used to perform the Fourier transform of the cutting forces to acquire the amplitude-frequency curve of the cutting forces fluctuation. The fluctuation of each cutting force component is analyzed, and the influence of trapezoidal chip break groove land width on tool vibration in the process of chip control is obtained: the frequencies of large amplitude of tool vibration along all directions in all stages of the chip crimped were the same; at the stage from the start of chip flowing into the chip breaker to the beginning of flowing into bottom of the chip breaking groove, as the increase of land width was increased, the amplitudes of tool vibration along the directions of feed and main cutting force were increased; in the stage of chip flow through the bottom of the groove, the amplitude of tool vibration along the directions of main cutting force was increased, but decreased along the direction of feed force with the increase of land width; in the stage of chip flow through the groove back, as land width increased, the amplitudes of tool vibration gradually decreased along the directions of feed and main cutting forces; the amplitude of the back force was smaller than the other two forces obviously. And the variation trend was not obvious.

In this paper, the multidisciplinary coupled dynamics simulation method and reliability modeling method are studied for the problems of low accuracy, stuck and strength degradation of aero engines. Based on the ADAMS software platform, the parametric modelling is proposed for aero-engine guide vane adjustment mechanism of variable geometry turbine, and the parametric model is simulated. The effects of dimensional uncertainty, component deformation, load uncertainty, strength uncertainty and strength degradation on the reliability of the mechanism are considered. Through simulation analysis, the key factors affecting the reliability of the mechanism can be identified and guidance can be provided for the establishment of the reliability model. Finally, the reliability of the mechanism regarding motion accuracy failure, stuck failure and strength failure was calculated by Monte Carlo method.

As TiNi alloy is in the pseudo elastic state, the stress-strain curve has a large hysteresis, which can consume energy and return to the origin after unloading without residual deformation. To study the energy absorption mechanism of TiNi alloy fixed beam under impact load, a drop hammer experiment was carried out. The experimental results show that under the impact of the drop hammer, the elastic bending wave is first generated at the impact point, and then propagates and reflects in the beam. Gradually, large deformation and phase transformation occur at the midpoint and fixed end of the beam, forming a phase transformation hinge. The rest of the beam rotates around the midpoint and fixed end. The axial force in the beam becomes the main factor of response. When the drop hammer speed is zero, the unloading phase is started. The elastic strain energy generated by axial force will make the drop hammer move upward and the speed will increase gradually. During the impact process, the energy dissipation is mainly completed by the phase change hinge. More energy is stored in the TiNi alloy fixed beam by the elastic strain energy generated by the axial force. The energy dissipation tends to increase with the increase of input energy.

Countersunk bolts are one of the main methods for joining carbon fiber-reinforced matrix composites (CFPR) in the aerospace field. In this paper, a study on the failure form and damage process of bending fracture behavior is carried out for the countersunk bolt connection structure of CFPR. Different preload forces were applied to the structure to study the three-point bending ultimate load and bending stiffness of the laminate, and it was found that the effect of preload on the bending stiffness and ultimate load of the specimen was nonlinear, and there existed a specific value of preload that made the bending stiffness and ultimate load of the structure reach the maximum value; the distribution of structural fracture cracks when different preload forces were applied was studied, and it was found that the increase of preload helped to suppress the lower laminate fiber direction. It was found that the increase of preloading force could help to suppress the parallel cracks in the fiber direction of the lower ply, but the effect on the vertical cracks was not significant. The main reasons for the increase in transverse cracks were also discussed.

In order to achieve energy conservation in actual navigation, based on the Rankine source method of potential flow theory, NSGA-II algorithm is used to study the design of energy-saving ship form in regular waves in this paper. Taking the geometric shapes at the bow and stern waterline of the KCS ship as the optimized design field, the FFD method is used to realize the parametric modeling and geometric reconstruction of the hull. The optimal trim and minimum EEDI are adopted as the objective function. Under the constraint condition of displacement, the NSGA-II algorithm is used to optimize the ship form with the optimal performance. The optimization results show that the wave-making resistance of the optimized ship form is reduced by 39.67% during the optimal trim, which verifies the feasibility of the research method proposed in this paper.

The vehicle kinematics model based on Ackerman principle has a wide range of applications in the field of unmanned driving, and the motion planning control of autonomous mobile intelligent vehicles is of great significance for the research of unmanned driving. In this paper, the robot operating system (ROS) is used as the development platform to establish the simulation model of Ackerman intelligent vehicle, and the three-dimensional physical simulation software Gazebo is used to build the simulation environment. The improved rapid expansion random tree (RRT) algorithm is used as the global path planning algorithm, and the TEB algorithm is used for local path planning to complete the simulation verification of the motion planning and control of the Ackerman smart car. The simulation results show that the improved RRT algorithm can obtain the optimal global path, and its search efficiency and path smoothness are significantly improved. Ackerman intelligent vehicle uses this algorithm to move autonomously in the 3D physical simulation environment, and can avoid obstacles in real time, presenting a good simulation effect.

Mounting a spike on the front end of hypersonic vehicles is an effective way to reduce vehicle drag. It is characterized by its simple structure, good drag reduction and some thermal protection. However, the thermal protection capability of the spike alone cannot meet the thermal protection requirements of hypersonic vehicles. Transpiration cooling is an effective active thermal protection method with strong cooling capacity, small amount of coolant and high system stability. Therefore, in this paper, we propose a new joint drag-reduction thermal protection configuration-spike-transpiration cooling configuration. It is used to address the problem of high thermal flux at the shock attachment point to a spike configuration. The spike configuration, the transpiration cooling configuration, and the spike-transpiration cooling configuration have been simulated numerically by solving the N-S equation, and their drag-reduction and heat-resistance properties have been analyzed. It is shown that the spike-transpiration cooling configuration is more drag-reducing and heat-protective than the single configuration when the length-diameter ratio is longer.

The underwater cleaning robot has a complex structure with numerous modules, and studying its hydrodynamic characteristics is crucial for improving its maneuverability and work efficiency during cleaning operations. In this paper, a hydrodynamic model of the underwater robot with a complex structure is established based on the viscous flow theory of the RANS equation. The sliding grid method is used for numerical calculation and research of the hydrodynamics of the underwater robot. Through simulation of different angles and speeds, the resistance performance and the influence of different angles of attack and sailing speeds are analyzed. The research can provide a foundation for optimizing the structural parameters and mechanical properties of complex underwater robots.

Most of the sound absorption methods in noise control used fibrous materials, which are prone to generate dust particles and other problems. Micro-perforated sound absorption structure can have good sound absorption performance without filling any sound absorption materials. It can effectively solve the problem of dust particles caused by fibrous soundabsorbing materials. Based on the micro-perforation theory, the sound absorption structure of double-layer composite metal plate is studied according to the acoustic and electrical analogy method, and the sound absorption performance of different size structures is calculated and simulated in MATLAB. The two structures with ideal simulation results are processed for sample preparation, and the performance test verification is completed in the reverberation room.

Aiming to improve the anti-interference capability and trajectory tracking accuracy of the robot control system that undertakes repetitive motion tasks, this work presents the trajectory tracking control along with a four degree-of-freedom parallel robot. By means of the principle of virtual work, the dynamic model of the robot was built for the model-based control design. A fuzzy adaptive iterative learning control algorithm was proposed by combining fuzzy control theory and iterative learning theory. Finally, the proposed algorithm was simulated and verified in comparison with the traditional iterative learning control algorithm, of which the results show that the proposed algorithm has robustness and higher tracking accuracy than the traditional one.

The telescopic boom with single cylinder and pinning system is an important structure of the Gantry crane. In order to avoid the serious consequences of resonance and the optimal design of the telescopic boom with single cylinder and pinning system, the three-dimensional modeling and finite element analysis of the telescopic boom were carried out using SolidWorks and ANSYS Workbench, respectively. The static analysis results, buckling analysis results and modal analysis results of the telescopic boom are obtained, which provides a reference for the design of this type of telescopic boom.

Aiming at the problem that the vibration signal characteristics of rolling bearings are unstable under the background of strong noise, resulting in poor generalization of the diagnostic algorithm, weak noise resistance, and difficulty in achieving effective fault diagnosis, a new method named improved convolutional neural networks with attention mechanism under high noise is proposed. Based on the deep convolutional neural network, the gated recurrent unit (GRU) is introduced to solve the gradient explosion problem in the neural network, the attention mechanism (attention) is introduced to improve the adaptive ability of the network and reduce the difficulty of hyperparameter selection, and the SVM classifier is used to replace the classification layer of the deep convolutional neural network to improve the accuracy of classification. In order to verify the robustness and generalization of the proposed method in a strong noise environment, the bearing dataset of Western Reserve University was used for verification. The experimental results show that the classification accuracy of the proposed algorithm is 24.7 percentage points higher than that of the WDCNN algorithm, which proves that the proposed method has good noise immunity and generalization under the background of high noise.

This paper presents hull strength analysis method for wind turbine units. First FEM model is created. Main deck, tween deck, inner bottom and bulkheads are created by shell and beam elements. The method for modelling the connection between legs and jacking systems is introduced in this paper. Then the loads for wind turbine units are summarized, including wind loads, wave and current loads, inertial loads and P-delta loads. The design criteria for hull strength analysis is also discussed. Last hull strength for a wind turbine unit is executed, and results show that the unit has adequate to support all the loads according to design conditions. Unlike other type of jack ups, the maximum stress always appears where the main crane locates, so the support structure must be strengthened specially. And more attention should be paid for leg well corner, especially where opening such as doors, manholes locate.

In this paper, a variety of hull/pod combination models are established, and steady and unsteady numerical calculation and analysis are carried out to study the flow characteristics of the stern and the hydrodynamic performance of the pod thruster at the design speed. The research results show that changing the layout of the pod has a small impact on the hydrodynamic characteristics, velocity field and pressure field, but the layout of the pod has a larger impact on the three-dimensional vortex structure and pressure pulsation characteristics. Relevant research results are of great significance for improving the hydrodynamic and vibration and noise reduction performance of passenger ships.

In order to improve the power and economy of the dual-motor four-wheel drive pure electric baja racing car, it is necessary to carry out the power matching research on the racing car. First of all, according to the design goal of baja racing car, the parameters of motor, power battery and main reducer are determined. Secondly, it is necessary to establish the 16-cycle driving condition of the car on the durable off-road track in baja, and simulate the speed in MATLAB software. Finally, the whole car model is built in AVL CRUISE software to simulate the power and economy of the car. The simulation results show that the designed car meets all the design indicators, which has certain guiding significance for the design of electric baja car.

In terms of the reliability simulation assessment model of x-type mechanical equipment, in line with different failure modes of miscellaneous parts, the x-type mechanical equipment was decomposed into a compressor, combustion chamber, gas turbine, control system, and auxiliary equipment. A model for an operational task was established, with a navigation time of 90 days. The duration met the requirements of the crew-level maintenance and support system for replacing and maintaining the parts. As supposed that the typically scheduled maintenance cycle of the equipment is 36 months, the lifespan of the device is longer than ten years from the use to irreparable functional failures or the fault rate exceeding the acceptable range [1].

To achieve the goal of the overall lightweight of wave adaptive unmanned ship, the front, and rear rods are taken as the research object. Workbench is used to perform static analysis on its 3D model, and then the topology optimization design method is used to optimize the shape of the removed material, and the static performance before and after optimization is compared. The results show that based on satisfying the stress and deformation requirements, the weights of the front and rear rods are reduced by 11.6% and 20.7%, respectively, ensuring that they can work properly, which verifies the feasibility of topology optimization.

Unexpected vibration of aero-engine blades may lead to fatigue failure. In order to reduce the harmful vibration of aero-engine blades, many smart materials have been employed for blade vibration suppression applications. Among them, a hot research area is vibration suppression using piezoelectric materials with damping circuits or active vibration control algorithms, by providing new and effective methodology to suppress the vibration of aero engines. This paper summarizes the current research status of vibration suppression for aero-engine blades using piezoelectric materials in recent years. Firstly, the structure of aero-engine and the background of vibration suppression are introduced briefly; secondly, the design process and several typical applications of passive vibration suppression and active vibration suppression methods are reviewed, their advantages and disadvantages are compared; finally, conclusions are made and some suggestions are summarized for the next generation smart structure aero-engine blades, such as the necessity of global geometry optimization and topology optimization, integrated structural/control optimization for engineering applications.

The door system is the system most frequently used by consumers. With the improvement of vehicle manufacturing accuracy and vehicle sealing level, the problem of ear pressure in the passenger compartment becomes prominent at the moment of closing the door. This paper analyses the influencing factors of human ear comfort. Based on STAR CCM+ overlapping grid technology, an analysis model of door closing ear pressure is established. The simulation analysis results show that the effective leakage area of airflow channel and relief valve is the main influencing factor of door closing ear pressure. The real vehicle test data shows that the simulation accuracy of this model can reach 96.81%, which can effectively analyses and prevent door closing ear pressure problems.

Fast nucleic acid analyzer has developed rapidly recently due to the spread of COVID-19 virus. In order to calibrate the temperature parameters of fast nucleic acid analyzer, it is necessary to study its temperature field distribution and temperature change curve, so as to put forward a scientific and accurate temperature field simulation model. This article studies the heat transfer mechanism of the heating module of the fast nucleic acid analyzer based on the finite element method by using CATIA three-dimensional modeling software and ANSYS Meshing platform, and the dynamic simulation model of the temperature field is obtained by studying two typical types of fast nucleic acid analyzers. Thus, this article provides a basis for the research on the calibration device of the fast nucleic acid analyzer, and the simulation model can be used to verify the reliability of the calibration device.

This project mainly designed an energy saving and emission reduction underwater manipulator design. Marine energy is abundant, and the development of this project can be used in marine monitoring, marine garbage cleaning, underwater object positioning, water pressure measurement and many other aspects. Combining sensor technology, Internet technology, camera technology and new energy and power technology, it is of great significance for marine energy conservation and emission reduction. We have established a simulation model of manipulator. The relevant manipulator simulation and dynamics simulation are studied to ensure the feasibility of the project.[1]

CFD is no longer strange to the public and industry in view of the rapid development of technology, some commercial software like Ansys Fluent has sprung up in the market, but their simulation is sometimes more complex and has certain limitations, so some self coding programme is used in order to cope with better simulation. In this paper, a python program was developed to simulate the transonic flow field above an airfoil, and some comparisons of results from the python program and fluent were discussed, as well as some potential improvements regarding to drawbacks of the python program were mentioned. As results, when mach number is 0.9, the velocity is about 260 m/s at the two edges of the wing, and have maximum around 680 m/s on the top, magnitude decreases as the distance to the aerofoil increases. When Mach number is 1.5, velocity is about 390 at the leading edge with an oblique shock and about 460 at the trailing edge. The runtime for programs are both about 35 s. For improvements, potentially can use list index method to optimize time complexity and add environment participation by introducing a new file as background environment.

With the development of human society, environmental problems have gradually become a hot issue of concern worldwide. Among all environmental problems, water pollution is one of the most important ones. Water pollution threatens the survival and development of human society. The good or bad condition of water quality is directly related to the quality of life of thousands of families, animals, and plants. Based on the above background, this project team designs a bionic jellyfish that can imitate physical movement through mechanical structures. We use the characteristics of the Disc reciprocating mechanism, Triangular three-link mechanism, and Slotted cam push rod telescoping mechanism to achieve different ways of jellyfish movement. For the bell-shaped body of the bionic jellyfish, we use waterproof and flexible material to make it to protect the internal mechanical structure and control unit. For the experiments, we use ANSYS 2022 to simulate the stress deformation of two critical parts of the jellyfish robot. The bionic robot’s various advantages, like small size, low energy consumption, and no environmental pollution, can monitor offshore and rivers’ water quality to better protect fish and other aquatic organisms. Moreover, it is very promising for science and education as well.

Bionics is a subject that studies various excellent performances such as the body structure, movement mode and information transmission of organisms in nature. The principles of these properties will give researchers a lot of new inspiration in terms of mechanical innovation. Provide new construction ideas for engineering manufacturing in practical applications. In this paper, according to the special fluid environment under water, the 3D model of the bionic snake-like robot with two degrees of freedom of pitch and yaw is drawn by using SolidWorks software. Then use the virtual prototype experimental platform Adams dynamics simulation software to analyze the kinematics state of the bionic snake-like robot. Simulate the motion state of each body module when the bionic snake-like robot snakes underwater. The simulation data results show that the overall structure of the bionic snake-like robot moves 0.8 m underwater and the average moving speed is 0.2 m/s. The maximum angular velocity in each module reaches 5.41 rad/s, the maximum angular acceleration reaches 34.9 rad/s² and the maximum rotational torque of the joint rotation mechanism reaches 0.08 N.m. During the whole test process, the bionic snake-like robot runs smoothly and the simulation experiment results provide theoretical data reference for the practical application of the prototype in the underwater environment in the future.

In this paper, the static stress calculation and fatigue analysis of the connecting rod of the crab bait cutting machine are carried out by ANSYS Workbench software. The results show that the safety factor at the root of the connecting rod is about 0.65, which is prone to fatigue. The problem is improved by increasing the cross-sectional area, and the response surface parameter optimization design is used to seek the optimal solution of each parameter of the connecting rod with the minimum safety factor and quality of the connecting rod as the goal. Finally, three candidate schemes are verified to obtain the best scheme. The quality of the optimized connecting rod is reduced by 10.52%, and the minimum safety factor on the connecting rod is 1.02, which improves the reliability of the connecting rod.

In view of the current situation that the design of fuze shear sheets safety mechanism is mainly based on experience, the theoretical analysis and numerical simulation of shear resistance and arming characteristics of fuze shear sheets safety mechanism is proposed. Firstly, the analytical relationship between shear resistance and the material and structural geometrical parameters of shear sheets is derived by theoretical analysis. Then, the simulation research is carried out on the arming characteristics, i.e., failure process, of the fuze shear sheets safety mechanism adopting commercial software ABAQUS, and the relationship between the material and structural dimension parameters of shear sheets and the shear resistance is verified. Finally, the design method of shear sheets is proposed based on analytic relationship. The comparisons between theoretical calculations and numerical simulations show that they are in good agreement. In addition, there is a linear relationship between shear resistance and material yield strength, thickness and out-of-plane chamfering of the shear sheets. When the shear resistance design value of the shear sheets is between 300 N and 600 N, for the shear sheets with out-of-plane chamfer of 0.1mm and thickness of 0.22 mm to 0.32 mm, the design range of the material yield strength is 125MPa~331MPa; for the shear sheets with thickness of 0.3mm and out-of-plane chamfer of 0.1 mm to 0.2 mm, the design range of yield strength of the material is 105 MPa~260 MPa. The research results of this paper provide significant guidance for the engineering design of shear sheets.

In order to solve the technical problem of large centrifugal compressors' tilting pad bearings in domestic production in China, this paper focuses on Type-one and Type-two tilting pad bearings, and proposes and uses a transient force feed back simulation technology based on FLUENT-UDF to address the low simulation efficiency issue of the general fluid-solid coupling. The operation characteristics of tilting pad bearings are studied. Through the simulation results, the possible causes of instability of the tilting pad bearings are obtained: unreasonable bearing structure and preloading, and an increased eccentricity of the journal leads to collision between the bearing and journal due to the low-pressure area between the bearing and journal. Moreover, an unreasonable bearing structure and excessive forced lubrication pressure can cause bearing deviation and collision with the journal due to the different pressure differences on both sides of the bearing.

Based on the stress wave theory, the optimal configuration of gradient aluminum foam is given. On this basis, a simulation model using three-layer gradient aluminum foam gasket is established, and two typical configurations and four impact angle conditions are numerically simulated. Simulation results show that the density of aluminum foam gradually decreases along the direction of impact load propagation is a better configuration, which is consistent with the previous theoretical analysis results, and the protective performance can be simply and effectively improved by changing the configuration of aluminum foam.

Aiming at the problem of the protection ability of the Whipple bumper shields under the action of millimeter-scale copper material space debris, the traditional Whipple bumper shields is studied, and the test of the protection ability of the Whipple bumper shields target plate against copper material debris is carried out, and the process of debris generation device forming debris and debris impacting the Whipple bumper shields is verified and studied through numerical simulation analysis, and the damage form of each layer target plate is analyzed, and the hole diameter of the Whipple bumper shields target plate is obtained fragment residual speed and other data. The results show that the copper space debris with an initial velocity of 1910 m/s penetrated the front and rear aluminum target plates of the Whipple bumper shields, and still had a high residual velocity after a hole with a minimum diameter of 10 mm was created on the aftereffect target, and penetrated an additional layer of aluminum alloy target plates, which proves that the traditional Whipple bumper shields has insufficient protection ability against copper space debris.

During the operation of an aero-engine vector nozzle mechanism, the properties of the material itself are subject to change as well as degradation. In this paper, the fatigue and time-dependent failure mechanism and damage evolution law and performance degradation law of mechanism components that may occur in service life cycle under various flight missions are studied, which are of great significance to the mechanism performance degradation law and its uncertainty characterization method. Meanwhile, this paper studies the strength reliability analysis model based on the Monte Carlo method with Latin hypercube improvement under a variety of flight missions, considering the strength degradation of mechanism parts and the dimensional dispersion, and provides some support for the reliability assessment and design of Axial-Symmetric Vectoring Exhaust Nozzle (AVEN) mechanism.

Aiming at the problem of performance degradation caused by the long-time running of the aero-engine rear variable area bypass injector, the fatigue strength of the components will be degraded under the action of load, and the degradation of the performance of these components will lead to the degradation of the performance of the mechanism, failing in the adjustment accuracy to meet the design requirements. The degradation will also lead to the failure of the mechanism to meet the speed regulation, resulting in the degradation of the engine's variable cycle, which in turn affects the overall performance of the aircraft flight.

Excavation damage zone (EDZ) has a great influence on the stability and support design for tunnels. To better describe the difference of EDZ in hard rock caused by tunnel boring machine (TBM) and drilling-blasting (D&B) method, the scope and degree of EDZ were considered. The scope of EDZ was determined by the test results from similar engineering. The degree of EDZ was determined by the Hoek-Brown criteria and the EDZ analysis of underground caverns. Combined with Ninghai pumped storage power station, FLAC3D was used to analyze the difference. For an access tunnel with a diameter of 9.80m, the displacement with the TBM method is about 65-80 % compared with the D&B method, and the depth of the plastic zone is only half. The analysis results are also consistent with field test results. Which means the analysis method is reliable and effective.

To get a thorough comprehension of how the traditional feedforward (FF) and feedback (FB) control affect the transmission of vibration, the damping performance of AVRS in different vibration source propagation paths is first analyzed theoretically. Then, according to the mathematical derivation and analysis, the mechanism of FF and FB joint control is revealed through a complete AVRS analytical schematic. Furthermore, by building the ADAMS and MATLAB co-simulation model of AVRS, the influence of the motor-driving force on the countertop velocity under the different disturbance combinations is simulated. Finally, the consistency between the theoretical analysis and the simulation results further illustrates the feasibility of the proposed method in the paper.

In this paper, the beam-strut composite system is taken as a simplified theoretical model, and the transverse vibration of the model is modeled by analytical method, and the reliability of the model is verified by numerical substitution. Based on this model, the influence of each mode of the system on the final displacement, the lateral vibration response of the system at different excitation frequencies and the influence of excitation displacement velocity on the lateral vibration of the system are analyzed. The results show that the higher the mode order, the smaller the influence of the mode on the final displacement of the system; the system will not resonate at the actual working frequency; the lateral vibration displacement of the system will increase with the increase of excitation displacement speed.

The air gap eccentricity fault of the motor will cause the distortion of the air gap magnetic field of the motor, so that the resultant force of the magnetic pull on the rotor circumferential direction is not zero, and the resultant force is unbalanced magnetic pull. Unbalanced magnetic pull will aggravate the vibration of the motor rotor, and even cause rub-impact fault between the rotor and stator, which will affect the safe and stable operation of the motor. In this paper, a rotor rub-impact fault model with air-gap mixed eccentricity is established, and then the rotor dynamic equation is solved by numerical simulation. The dynamic characteristics of the rotor under different fundamental MMF (Magnetic Motive Force) are compared by time domain waveform, spectrum, axis trajectory, Poincare map and bifurcation diagram. The results show that there is no rub-impact fault in the rotor system at low speed, and the unbalanced magnetic pull will make the rotor produce zero frequency, fundamental frequency and second harmonic components; with the increase of rotating speed, rub-impact fault occurs in the rotor system. At this time, the existence of unbalanced magnetic pull enhances the nonlinear characteristics of the rotor.

To suppress pulse width modulation (PWM) harmonics in the permanent magnet synchronous motor (PMSM) systems, a novel random pulse position space vector PWM (RPP-SVPWM) technique is proposed in this paper. In the proposed RPP-SVPWM technique, a high-performance Tiny Mersenne Twister (MT) algorithm is used instead of a linear feedback shift register (LFSR) to construct a pseudo-random number generator (PRNG). Meanwhile, the technique takes into account the effect of the modulation index (MI). A random pattern of pulse positions is chosen according to the magnitude of the modulation index. When MI ≥ 0.5, the random degrees of freedom are increased by randomizing the action time of the zero vector. Accordingly, the diffusion effect is improved at high modulation indexes. Then, the impact of LFSR-PRNG and Tiny MT-PRNG on the PWM harmonic suppression effect under different modulation indexes is investigated. Finally, simulation results are analyzed to evaluate the performance. This study is expected to provide a reference for the random pulse position SVPWM technique to suppress PWM harmonics in integrated PMSM drive systems.

Aiming at the switching production mode of 4+n multi car series in a domestic luxury independent brand welding workshop, a new module production mode is formulated by combining three production modes of order production, pull production and high module production. The MES system is used to schedule the production plan of the welding workshop, reorganize and form independent module orders for each line, so as to meet the demand of 4+n car series on-line production at the same time. At the same time, by using the characteristics of each line, the position of each sub assembly line is monitored in real time through PLC, and the current production model is identified, detected, and information converted at the key position. At the same time, the corresponding solutions to the planned and unexpected situations are formulated.

In this paper, the flow field in a thermal launch canister is taken as the research object, the simulation model of the launch canister is established based on CFD, and the dynamic grid technology is adopted to simulate the flow field in the launch canister with or without the diversion disc structure, and the simulation results are analyzed. Through the relevant discussion in this paper, it provides a method and idea for the structure design of the thermal launch canister, which has certain reference value for the subsequent optimization and design of the structure of the launch canister.

For the power requirements of diesel engine and permanent magnet synchronous generator in the full permanent magnet synchronous traction drive system of internal combustion locomotive, it is necessary to study the method to adapt the output voltage of permanent magnet synchronous generator under different working conditions of diesel engine for fast and accurate detection. Based on the analysis of the principle and structure of the phase-locked loop with single synchronous coordinate system software, a model is built based on the Simulink simulation platform, and the operating characteristics of the phase-locked loop are simulated and tested under different operating conditions of diesel engines. The results show that the single-synchronous coordinate system phase-locked loop can quickly achieve the monitoring of voltage amplitude, phase, and frequency under different operating conditions.

This article builds a finite element thermal model of a spacecraft in low-Earth orbit, applies the equivalent steady-state infrared heat flow to simulate the on-orbit thermal environment, and obtains the spacecraft temperature field and thermal deformation field. The analysis results show that the finite element modeling method adopted in this paper can well simulate and analyze the thermal deformation test based on the absorbed heat flow, and provide an important reference for the design and test of the spacecraft.

In view of the difficulty in building and low stability of the substation equipment maintenance anti-fall support on complex terrain, a three-dimensional configuration model of the safe position of the substation equipment maintenance anti-fall support is designed. Build a three-dimensional configuration model of the safe position, use the direct integration method to verify the parameter stability, ensure that the support maintains the same plane on the sloping terrain, and take into account the height change and avoid the shadow between the equipment, and obtain the safe position with the best stability coefficient to support the support. The result of the example analysis shows that the stability coefficient of the model has been improved to a certain extent under different orders.

In order to simplify the method of human-computer interaction, through the analysis and research of the motion capture system and the robot arm system, a motion imitation platform based on the Marker ball motion capture system combined with the six-axis robot arm was built. The collected coordinate data is obtained through the inverse kinematics solution of the robot to obtain the joint Angle data of the manipulator, and the trajectory of the joint angle is smoothed by MATLAB simulation software. The simulation was carried out based on the RoBoDK simulation environment. The simulation experiment results showed that the motion reduplication method could be applied to the imitation of human arm movements by the robot arm, and the motion accuracy could meet the working requirements, and the motion imitation effect was good.

To study the gas and liquid flow characteristics inside the diaphragm compressor and optimize the structure of the gas and oil chambers to improve the overall reliability of the machine, the CFD method was used to establish fluid models for the gas and oil chambers separately. The velocity and turbulence energy distribution of the gas chamber, as well as the pressure and flow velocity distribution of the oil chamber, were obtained. Various layout schemes for the gas and oil holes were optimized and compared. The results showed that the maximum flow velocity and turbulence energy of the gas chamber for scheme one were greater than those of the original design, but both decreased gradually for schemes ne to four. The centering of the distribution hole in the oil chamber had a significant effect on fluid characteristics, and the results from schemes one to four indicated that as the hole diameter increased, the maximum flow velocity and pressure gradually decreased. Additionally, under the condition of ensuring that local stresses were not too high, the fourth scheme was the optimal solution for both the gas and oil chambers. The maximum turbulence energy of the gas chamber decreased by 29.1% compared to the initial structure, and the maximum pressure and velocity of the oil chamber decreased by 35.5% and 71.5%, respectively.

Pumped storage power station is a device that converts surplus electrical energy into potential energy at low power load valley, mainly by pumping water from the lower reservoir to the upper reservoir through a large turbine unit, and converting potential energy into electrical energy at peak power load; in the study of the unit harmonic problem is the most important is to analyse the static inverter SFC dragging process, but the difficulty of its unit modelling is very great, so an equivalent replacement method is proposed not only to simulate not only the transient process of harmonic generation and transmission when the turbine unit is switched, but also the steady-state process in its stable phase. After a comparative analysis of the principles, this improved modelling was also verified by simulation to be an equivalent replacement.

The frame is the carrier and substrate of almost all parts on the bogie, which connects the motor drive and a series of suspension devices together through the axle box tie rod, and is used to transmit the vertical force from the car body and to bear the load from the wheel pair in various directions. This thesis is based on EN13749, UIC615-4, JIS E 4207 and JIS E 4208 standards to perform finite element analysis of the bogie frame, and the static and fatigue strength tests of the frame were conducted in the laboratory to compare and analyze the simulation and test results. The results show that the static strength results of the bogie frame are less than the allowable stress of the corresponding material. The maximum stress of the frame in the extraordinary service load occurs in service ten with a stress of 250.44 MPa, which is located at the transition arc between the frame crossbeam and the longitudinal connection beam. In the operating condition load, the maximum stress of the frame occurs in condition eight with a stress of 142.47 MPa, which is located at the transition arc between the frame crossbeam and the longitudinal connection beam. In the JIS service load, the maximum stress of the frame occurs in service ten with a stress of 167.85 MPa, which is located at the weld joint between the bogie frame cross member and the motor hanger. Fatigue assessment by Goodman diagram, the results show that the data are all within the envelope and meet the fatigue assessment requirements. Comparing the results of static strength and finite element simulations, it is concluded that the relative error between simulation and test results is controlled within 20%. After verification of ten million fatigue tests on the bogie frame structure and non-destructive testing at each stage, the results showed no cracks and met the fatigue test evaluation requirements in the standard.

Based on the current radar structure development, support features and digital twinning technology advantages, a radar electromechanical-hydraulic digital twinning system architecture is designed, through the key technologies such as mechanical-electro-hydraulic system simulation, training data cleaning and filtering, ROM model building and precision verification, digital twinning model encapsulation, real-time response SDK file generation, etc., a digital twinning model for the electro-mechanical and hydraulic system of radar is constructed, which is uniformly deployed in the digital twinning software platform of radar structure, and integrates the functions of system data acquisition, Twinning model construction, high-precision dynamic simulation, etc., by obtaining the accurate real-time digital simulation model, the equivalence of the simulation data and the measured data of the physical prototype is realized, and the real-time update of the visual simulation of the radar stand-down system is realized, thus, the reliability and maneuverability of the stand-off system are improved, and it is possible to realize the state visualization and health monitoring of the electromechanical-hydraulic system.