Torsional modes in piezo helical springs

Piezo springs have been studied for their advantages in receiver applications at low frequencies. In this paper, piezo helical springs shaped from curved unimorphs are proposed for actuator designs in which the torsional modes are used to obtain electroelastic conversion. In comparison with the use of bimorphs as low frequency actuators, the helices show advantages of large strain capabilities and high compliance. These advantages are confirmed by numerical calculations.