Shape memory alloys (SMAs) are a class of metallic alloys which possesses attractive mechanical properties when subjected to stress and/or temperature changes.
An SMA has two different solid phases: austenite, which is stable in stress-free state at high temperatures, and martensite, which is a low-temperature stress-free state phase. The pseudo-elastic behaviour in SMAs is observed above the critical temperature when in the equilibrium stress-free configuration austenite is stable.
Shape memory alloys are being used in various applications, and their dynamical applications are associated with both the adaptive dissipation of energy related to their hysteretic behaviour and large changes in their mechanical properties caused by phase transformations. These aspects can be explored both in the adaptive passive and the active control.
Some interesting SMA applications arise in dynamical systems with impacts. A prototype of this kind of system capturing the most important features is an impact oscillator with the secondary support made from SMA. This project explores the nonlinear dynamics of such impact oscillator both numerically and experimentally focussing on potential vibration reduction based on the high dissipation capacity of SMA due to hysteresis loop.