Dynamic Anti-plane Behavior Of The Interface Circular Cavity In Bi-material Piezeoelectric Media

Piezoelectric materials have been more and more widely used in smart materials such as electromechanical sensors, transducers and actuators due to their strong electromechanical coupling characteristics. The present thesis investigates the scattering problems of SH-waves by an interface circular cavity. Green's function method is used in this paper. The first important work is to develop a suitable Green's function. Once the special Green's function is obtained, various scattering problems of SH-waves by a kind of interface blemish or complex flaw will be solved. The model of the problem is composed of two half spaces with half cylindrical gaps. Horizontal surfaces of the two half spaces are loaded with undetermined anti-plane forces in order to satisfy continuity conditions at linking section. A series of Fredholm integral equations of first kind for determining the unknown forces can be set up through continuity conditions that are expressed by use of the Green's function. For the model of interface circular cavity, the additional force at horizontal interface with a semi-circular cavity is related to the dynamic stress concentration factor. The integral equations for determining the unknown forces can be transformed into algebraic equations and solved numerically. The work concludes mainly the following contents.First, in terms of wave functions expansion method and Graf formula, a construction method is given for the special Green's function. Green's function is a fundamental solution of displacement field for an elastic half space with a half cylindrical cavity subjected to a time-harmonic out-plane line source loading at horizontal surface. The continuity, singularity, convergence and way of application of Green's function are discussed respectively.Second, scattering of SH-wave by an interface circular cavity and solution of electromechanical field are investigated. By combining two half spaces with unknown loading at interface into an infinite elastic piezoelectric body, the interface circular cavity can be formed. Integral equations to determine the unknown loading are established by use of Green's function. Expressions of electromechanical field including dynamic stress concentration factor around the interface circular cavity are obtained.At last, some examples are given and plotted to show how the influence of wave number, incident wave orientation and combination of different piezoelectric media parameters upon dynamic concentration factors. Meanwhile the calculating results are discussed and some are compared with related documents.