Shape memory alloys (SMAs) have long been utilized as semi-active elements for the attenuation of unnecessary vibration in engineering structures. By leveraging properties of different material phases, energy dissipation capability of smart structures integrated with SMAs can be enhanced and a certain degree of tunability subjected to temperature or stress stimuli can be achieved. In this paper, the influence of axial pre-strains on the dynamic characteristics of a pinned-pinned beam at different operating conditions was systematically and comprehensively investigated. To model the material nonlinearity of SMAs, the improved one-dimensional (1D) Brinson's model with tension-compression asymmetry is exploited. The constitutive relation was integrated into the finite element model of considered SMA beam, in which geometric nonlinearity in the von Karman sense is included as well. Free and forced vibration of the SMA beam under different levels of pre-strains as well as operation conditions were analyzed. For the free decaying of SMA beam, it was observed there exists optimal pre-strain that can achieve maximum damping performance. In the forced vibration analysis, the jump phenomena in amplitude-frequency properties of SMA beam were evaluated and compared to the equivalent elastic beam. The results imply that the pre-strains affect the vibration of SMA beam distinctly at different operating temperatures as well as frequency regions. The conducted analysis can provide guidance on fully exploiting dissipation properties of SMA lamina in the development of composites.
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