Parametric Study and Experimental Correlation of an SMA Based Damping and Passive Vibration Isolation Device

In this work, the effect of pseudoelastic response of shape memory alloys (SMAs) on damping and passive vibration isolation will be presented. This study has been conducted by developing and utilizing a shape memory alloy (SMA) model (a physically based SMA model) to perform extensive parametric studies on a non-linear hysteretic dynamic system, representing an actual SMA damping and passive vibration isolation prototype device. The prototype device consists of SMA tubes undergoing pseudoelastic transformations under transverse loading. To accurately model the non-linear hysteretic response of SMA tubes present in the prototype device, a Preisach model (an empirical model based on system identification) has also been modified to simulate the response of the prototype device. Both the simplified SMA model and the Preisach model have been utilized to perform experimental correlations with the results obtained from actual testing of the prototype device. The investigations show that variable damping and tunable isolation response are major benefits of SMA pseudoelasticity. Correlation of numerical simulations and experimental results has shown that large amplitude displacements causing phase transformations of SMA components are necessary for an SMA based vibration isolation device to be effective in reducing the transmissibility of a dynamic system. It has also been shown that SMA based devices can overcome performance trade-offs inherent in a typical softening spring-damper vibration isolation system. In terms of modeling, the Preisach model gave relatively accurate results due to close proximity in predicting actual SMA component behavior. However, for a generic parametric study, the simplified SMA model has been found to be more useful as it is motivated from the constitutive response of SMAs and hence, could easily incorporate different changes in system conditions.