Abstract: A systematic study was performed for a piezoelectric layer with a central penny-shaped crack bonded to an elastic layer. Both the piezoelectric and elastic layers are made of transversely isotropic materials, are infinite along the r-axis, and have finite thickness in the z-direction. The polarization direction of piezoelectric material is along the z-axis. Electrically impermeable crack assumption is adopted. Hankel transform technique was used to transform the problem into a system of integral equations. The field intensity factors and energy release rate were derived and calculated. Numerical results were presented graphically. The influence of thickness of elastic layer on field intensity factors and energy release rate was investigated.