Proceedings Article | 3 April 2019
KEYWORDS: Wave plates, Composites, Transducers, Wave propagation, Manufacturing, Sensors, Dispersion, Ceramics, Inspection, Particles
Smart composite structures, which are able to modify their mechanical properties with respect to their environment (e.g. active vibration control), to interact with other structures (e.g. mechatronic) or with human beings (e.g. Human-Machine Interaction), are widely used in the modern industrial fields (e.g. aerospace), due to the intensification of the operational dynamic environment and an increase of durability requirements from the customers. Conventionally, the piezoelectric transducers are glued on the surface of the structure and the power and control electronics are away. To protect the transducer elements and their connections and develop some industrially products in "plug and play" mode, a smart composite structure is designed and manufactured in our lab, a wide distributed network of piezo ceramics elements has been integrated into the heart of the composite during the manufacturing process of composite structures. To meet the technical specifications of smart composite structures, in particular for complex geometries, it is necessary to master the manufacturing process and consequently the material parameters of the manufactured composite. Indeed, during the preliminary design phase, these parameters have to be absolutely known. A design approach based on engineering system theory and uncertainty calculation is applied to characterize the smart composite structures manufactured. In this paper, a Time-of-Flight method is developed in order to extract the elastic properties of smart composite structures. This technique is based on the duration measurements of wave propagation with a simple and low-cost experimental setup. Integrated piezoelectric transducers are used as both transducer and actuator. This method operates the intrinsic abilities of smart composite structures, it is much easier and faster than the model techniques, which are widely used nowadays. Especially for Poisson’s Ratio, this method can extract this parameter rapidly without any complex numerical model by analyzing the phase changes of output signals. In fact, the received waveform contains two types of waves, symmetric and antisymmetric, the elastic properties can be directly calculated based on plate wave propagation theory. In this research, a set of plates with piezo ceramic on each corner are manufactured, the elastic properties of the chosen material are accurately known. Then the Time-of-Flight method will be used for extracting the elastic properties of the plates. A series of sinusoidal burst signals (with different cycles) were chosen as input signals, the idea is to identify the parts where they are in phase from the superposition of the output signals. From the first part of the output signals, there were two areas in phase, they were assumed to be the responses of S0 wave and A0 wave, then the Passion’s Ratio is calculated. At the end, the test results and the known parameters of each plate were compared and discussed.
