Response characteristics of SMA actuator in audio frequency range

Abstract

We aim to use Ti-Ni based shape memory alloy (SMA) actuators as a new sound source by driving them in the audio frequency range. In this paper, we present the results of an experimental study on the driving conditions that maximize the output sound pressure for a single frequency input in the audio frequency range, especially the difference in response depending on the amount of strain of SMA. The results of sound pressure measurements using a microphone indicated that the magnitude of the response depended on the amount of strain of the SMA, and that in most cases the response could be maximized by maintaining the strain in the middle range where phase transformation occurs.