Design and Experimental Study of a Down-Drive Piezoelectric High-Frequency Fatigue Testing Machine

In order to solve the problem of large dynamic load and low loading accuracy prevailing in traditional fatigue testing machines, and to meet the fatigue test loading demand of alternating small-load microelectromechanical devices and bionic devices, a high-frequency resonant piezoelectric fatigue tester that can apply alternating small loads in the range of 0.1 N~100 N was designed and manufactured, with a piezoelectric oscillator as the driving source of the system. Firstly, the structure of this fatigue testing machine is designed, and a dynamic model is established for the fatigue testing machine to theoretically study the influence of the system mass and stiffness on the change in the resonance frequency of the fatigue testing machine. Then, numerical calculations and experiments are carried out to verify the effect of system mass and stiffness changes on the intrinsic frequency of the fatigue testing machine. Finally, the fatigue testing machine was used to carry out fatigue test on the dog-bone-shaped specimens, and the failure process of specimen fatigue was verified by analysing the load applied to the specimen by the fatigue testing machine, and at the same time, it was proved that the performance of the present fatigue testing machine complied with the requirements. It provides a new technical means to meet the fatigue test loading demand of small-load electromechanical devices and bionic devices.