Antiplane shear waves from a piezoelectric strip actuator: exact versus effective boundary condition solutions

Artikel i vetenskaplig tidskrift, 2004

A piezoelectric strip of finite width and thickness is placed on top of an isotropic half-space. It operates in actuator mode and a time harmonic voltage is thus applied across it. The piezoelectric material is of type 6mm oriented so that a 2D antiplane (scalar) problem results. By Fourier series expansions the problem is solved exactly and this result is compared to the case when the piezoelectric strip is replaced by an effective boundary condition, which is derived by series expansions in the thickness coordinate in the piezoelectric strip. At low frequencies the results agree very well and this corresponds to the situation usually found in practice. In general the effective boundary condition should be easier to apply and it is in particular noted that this is the case when using a FEM program where the option of a piezoelectric material is usually not available.