Enhanced piezoelectric coupling by a line inclusion in piezoelectric medium associated with nonlocal theory of elasticity

An line inclusion in a polarized medium with nonlocal effects for both the stress and electric displacement is studied. The inclusion can be mechanical rigid and electrically conducting, mechanical rigid and electrically insulted, or a electrically conducting crack. The mechanical and electric fields and the equivalent elastic, piezoelectric and dielectric constants of the enhanced piezoelectric medium system are obtained. Due to nonlocal effect, stresses and the electric displacement at the inclusion tips are significantly lower than those from the classic piezoelectric analysis. The piezoelectric effect is also found to be enhanced due to the rigid and electrically conducting inclusion. The analytical model is general enough since it can deal with the effects of the nonlocal effect for a finite inclusion in a finite piezoelectric medium.