Experimental Researches On Hysteretic Nonlinearities And Impact Properties Of Piezoelectric Structures

Piezoelectric materials are widely used as smart materials for their stable piezoelectric properties. Ultrasonic motors and piezoelectric power generators are two typical applications of piezoelectric materials in engineering. As the undesired hysteretic nonlinearities being inherent in piezoelectric materials, it is important to research the hysteretic nonlinear dynamics of piezoelectric materials.In this paper, the cubic polynomial model was analyzed and improved firstly, and some experiments on hysteresis of piezoelectric ceramic laminate were carried out. Secondly, the nonlinear behavior of ultrasonic motor was measured and analyzed. Finally, by using impact test equipment, some experimental researches were done to investigate the impact responses of the piezoelectric ceramic laminate. The major work of the paper was summarized as follows:(1) The properties of piezoelectric materials and their applications in ultrasonic motors and power generator were introduced briefly. The development of hysteretic nonlinearities of piezoelectric materials, nonlinear dynamics of ultrasonic motors, as well as impact properties of piezoelectric structures is summarized.(2) The applicable condition and related parameters of the cubic polynomial hysteresis model were analyzed qualitatively by comparing it with the other hysteresis model. Based on the above analysis, one improved piezoelectric hysteresis model was proposed.(3) With rotary traveling wave ultrasonic motor's feedback voltage and rotor speed measured, the dynamic responses of the stator and the rotor were measured and some nonlinear phenomena were found.(4) The impact test device was invented by analyzing and measuring the size and mode of piezoelectric ceramic element. The impact responses of piezoelectric ceramic laminates and the maximum carrying capacity of piezoelectric ceramic elements were measured to ensure piezoelectric ceramic element work normally. The generating power of piezoelectric structure was tested. All these results would make a foundation for further theoretical research of piezoelectric power generators in future. The results given in this thesis provide a basis for the applications of the cubic polynomial hysteresis model and the model of whole system of ultrasonic motor, and make a foundation for theoretical research of mechanical and electrical responses of piezoelectric structure.