Problems Of SH-wave-induced Dynamic Stress Concentration In Piezoelectric Media With Defects

Due to unique electromechanical coupling characteristics, piezoelectric materials have beenwidely used in smart structures, such as underwater acoustic transducer and frequency controller andultrasonic motor. But the existence of effects such that holes and inclusions in the piezoelectricmaterials may lead to high dynamic stress concentration when these materials are subjected todynamic loads, and finally it may result in the final failure of the smart structures. Therefore, it is oftheoretical and practical importance to study the dynamic stress concentration problem of thepiezoelectric materials with defects.Based on wave function expansion method, combined with the conformal mapping function andGreen’s function, the problems of dynamic stress concentration by SH wave in piezoelectric materialswith defects are studied. Below are the main contents of the work: a brief introduction onpiezoelectric materials and previous works is given in Chapter1. Basic equations and some basicproperties of Green functions are outlined in Chapter2. In Chapters3and4, the dynamic stressconcentration in an infinite piezoelectric media with a circular inclusion and an elliptical hole by SHwave is discussed, respectively. Some numerical examples are also presented to investigate the effectsof different material parameters and incident conditions on the distributions of dynamic stressconcentration factors at the interface. In Chapter5, using Green function, the dynamic stressconcentration induced by SH wave in piezoelectric media with an interface circular cavity is studied.By formulating the mechanical and electric Green functions, the expressions of dynamic stress aroundthe interface hole can be derived based on the continuous conditions at the interface. Finally, severalnumerical solutions for special cases of an infinite piezoelectric media with a circular cavity arepresented and compared with those in the existing literature.Finally, this work is concluded and future works on the topic are proposed in Chapter6.