Simulation of Payload Vibration Protection by Shape Memory Alloy Parts

A vibration protection system using shape memory alloy (SMA) parts is considered. Simulations based on the use of a microstructural model are made for the cases when an external excitation is either a harmonic or an impact-type displacement. The SMA isolators are considered to be in the austenitic (pseudoelastic) state, two-phase state or in the martensitic (pseudoplastic) state. The mechanical properties of the isolators (stiffness and damping ability) can be changed by cooling or heating, which causes the direct or reverse phase transformation. This change of the isolator’s properties gives a possibility to change the resonant frequency of the system and escape from the resonance, when it occurs. Another effect is the passage on cooling from the regime of isolation to the regime of damping or the reverse transition on heating. It is shown that SMA with the narrow hysteresis are better for the vibration control as they provide a bigger change of the stiffness than the alloys with a wide hysteresis. In the case of a short impact-type external displacement a better performance is secured by an isolator in the austenitic state due to a non-linear force-displacement characteristic. A comparison with the experimental data has shown a good qualitative agreement.