Frequency tunable vibration and shock isolator using shape memory alloy wire actuator

Abstract

Launch vehicles and satellites experience severe dynamic loads during flight phases. In particular, pyroshock generated from several separation events could result in malfunctions in the electric components in the launch vehicles. Shock isolators are generally applied in order to attenuate these severe shock environments; however, these isolators could amplify the low-frequency vibration generated by the engine thrust and aerodynamic loads and reduce the payload stability. When the natural frequency of the isolator is increased in order to avoid the low-frequency vibration amplification, sufficient shock attenuation could not be obtained. Thus, the isolators used in launch vehicles need to be designed with trade-offs between the low-frequency vibration amplification and the pyroshock attenuation. This article presents a novel frequency tuning method for the isolator in order to achieve both shock attenuation performance and avoidance of the vibration amplification. Compressed mesh washer isolators using the pseudoelasticity of shape memory alloy were adopted for easier attainment of the frequency tuning with a high performance in the shock attenuation.