Scattering of SH-guided waves by circular holes in functionally graded piezoelectric ceramic slats

In this article, the scattering and stress concentration problems of circular hole defects in an infinite-length functionally graded piezoelectric ceramic slab structure are analyzed under steady-state force and an electrically coupled SH-type guided wave. First, the guided wave expansion approach is employed to construct the plane SH-guided wave. Second, the scattering wave whose upper and lower boundaries fulfill both stress-free and electrical insulation conditions is constructed by the repeated mirror method. Finally, the linear algebraic equations with unknown coefficients are obtained in accordance with the conditions of stress freedom and electrical insulation at the boundary of the circular hole. The numerical results of the problem can be obtained by truncating the finite terms on the premise of ensuring accuracy. Through the discussion of dimensionless parameters, the effects of SH-guided wave order, non-uniform parameters, thickness of ceramic plate, and wave number of incident guided wave on the dynamic stress concentration factor and electric field intensity concentration factor around a circular hole are analyzed. The numerical results show that choosing the appropriate waveguide order, effectively controlling the non-uniform parameters, and cleverly designing the plate thickness can all reduce stress concentration and play a crucial role in protecting the functionally graded piezoelectric plate from destruction. This method's research provides an important theoretical basis for applying SH waveguides to the nondestructive testing of functionally graded materials.