Applications Of Shape Memory Alloys In The Whole-spacecraft Vibration Isolators

At the launching stage, the dynamical environment of a satellite is very complicated. In order to protecting the satellite from being destroyed, the whole-spacecraft vibration isolation?WSVI? systems are supposed. Shape Memory Alloy?SMA? is one type of functional materials with wide application prospect. Besides shape memory effect, SMA have the properties of pseudo-elasticity, corrosion resistance and high damping. SMA has attracted more and more attentions and has been extensively used in aerospace, aviation and machinery fields. Based on the high damping feature, the Ti₅₀Ni_37.5Cu_12.5 SMA is embedded into the whole-spacecraft vibration isolation systems, improving the vibration inhibition capacity.The main research content of the paper are listed as follows:First, the dynamical model of the WSVI system, which includes SMA, was established. Bilinear double loop hysteresis model was used in establishing the restoring force of the SMA. The amplitude-frequency response equation of the WSVI system was attained using the averaging method for analyzing a multi-degree-of-freedom oscillation system. The control effect of the SMA on the system response is attained using numerical simulation.Second, using cantilever beam with free ends made of Ti₅₀Ni_37.5Cu_12.5 SMA as the research object, the frequency response function?FRF? is attained through experiments. The modal damping ratio was attained using the modal identification method. The experiment result proved the high damping characteristics of the SMA.Finally, based on the theory and the experiment, the test model of the WSVI system including the SMA was established. The control effect of the SMA to the whole vibration isolation system was analyzed by the longitudinal vibration control test.The following conclusions can be drawn: at low frequencies, the SMA inhibitory effect for the acceleration response of rigid satellite can reach 35.9%. At higher frequency band?220- 700Hz?, the vibration suppression effect is very well?except for the resonance peak of 670Hz?. The first three resonance frequency changes of the analog satellite-vibration isolation system lie in an acceptable frequency range?40-200Hz?. Results showed that the satellite vibration control tasks of the full frequency band?10-700Hz? can be achieved by designing a simple structure WSVI system containing SMA, which can meet the harsh requirements of space launch qualification and improves structural reliability.