The scattering of SH guided wave by a circular cavity in an infinite piezoelectric material strip is analyzed by using “mirror image method” and guided wave theory, and the analytical expressions of guided wave function satisfying stress free and electric insulation conditions on the upper and lower horizontal boundaries of the strip domain are obtained. The analytical expression of the scattered wave around a circular cavity is constructed by using the method of multiple mirror superposition and wave function expansion. The integral equations are established and solved by the boundary conditions of the circular cavity, and the analytical expressions of the dynamic stress concentration factor and the electric field intensity factor are obtained. The effects of incident wave frequency, dielectric parameters and circular cavity position on electric field intensity concentration factor (EFICF) and dynamic stress concentration factor (DSCF) are analyzed by numerical examples. Besides, the analytical solutions obtained in this article are compared with the finite element solutions and the analytical solutions in previous literature to verify the correctness and accuracy of the conclusions in this article. And the conclusions in this article are of great reference value to the selection and ultrasonic nondestructive testing of anti-seismic materials.

The problem of dynamic stress concentration in anti-plane motion of a single circular cavity in a serrated boundary strip medium is studied. Firstly, the scattering of SH wave by a circular cavity defect in the straight line boundary strip medium is analysed based on guided wave theory. The scattering of waves around a circular cavity is expressed as series form by the employed wave function expansion method, and compatible scattering guided waves resulting from the reflection of waves off the boundaries of the elastic strip is constructed by repeated image superposition. The coefficients of the wave function expansion are determined based on the stress free condition of circular boundaries with pre-given incident guided waves. Then the center of the cavity is respectively moved to the upper and lower boundaries to form a depression, and the scattering of the SH-wave by the cavity in the strip with the depression is analyzed. The results of finite element method and analytical method are used to verify each other. A number of depressions are set up at the boundary to simulate a serrated boundary. Then the finite element method is used to analyze the SH wave scattering problem in the serrated boundary strip. GRAPHICAL ABSTRACT