High frequency, large displacement, and low power consumption piezoelectric translational actuator based on an oval loop shell

Compact piezoelectric actuators based on an oval loop shell structure were fabricated and their vibration characteristics were investigated. The actuators can successfully create a translational motion at a high frequency and a large displacement working distance at the second resonant mode of the shell structure. As a result of a shot peening process to harden the surface and increase the strength of the shell structures, fatigue limits were enhanced. The highest operating frequency of 1444 Hz was achieved with about 1.5 mm translational displacement under an applied voltage of 100 VAC. The largest amplified displacement of 2.1 mm was obtained at a resonant frequency of 961 Hz. Displacement amplification ratios between static and resonance conditions are presented and compared. A theoretical approach was provided to estimate the natural frequencies of the oval loop shell actuators. The estimated natural frequencies of the actuators agreed with experimental values to within 12%. In addition, load bearing capacity and efficiency of one of the shell actuators was evaluated with an experimental method. The calculated actuator efficiency is around 55% when 3.1 g of mass is loaded to the actuator and an applied voltage of 140 V is applied. A possible application of the actuator, a cooling device, was demonstrated by providing its configuration and test results.