Suitability of Shape Memory Alloys for vibration isolation with application to launch vehicle payloads

Abstract

This work details an investigation into the suitability of Shape Memory Alloys for the task of vibration isolation based on the similarities between the Shape Memory Alloy pseudoelastic behavior and the softening response of isolators whose response is similar to a buckling elastomer. In this work, a simplified material model for the prediction of the non-linear, hysteretic nature of the pseudoelastic force-displacement relationship is developed. This material model is coupled with the numerical simulation of a dynamic system whose restoring force is provided by Shape Memory Alloys, providing an efficient software tool for the modelling of such systems. A thorough experimental investigation is also presented in which the behavior of a prototype Shape Memory Alloy-based isolation device is explored. Numerous quasi-static tests are performed, as well as a comprehensive series of dynamic tests on the prototype device. Results of these tests are compared with the predictions of the numeric simulation. From this comparison, several important conclusions are drawn concerning the application of Shape Memory Alloys to vibrating systems. The most important conclusion is that in order for the non-linearity and hysteresis present in Shape Memory Alloys to be effective in reducing the transmissibility of a dynamic system, there must be large amplitude deflections in the system.