Fracture analysis on the arc-shaped interface in a layered cylindrical piezoelectric sensor polarized along its axis

Fracture analysis is performed for the arc-shaped interface in a layered cylindrical piezoelectric sensor polarized along its axis. Parametric studies on the numerical results of the singular integral equation yield three guidelines for optimal designs of cylindrical piezoelectric sensors made for axial shear testing. (a) The optimal value of the radius ratio is from 1.1 to 1.5. (b) A stiff piezoelectric layer plus a soft central cylindrical substrate can generate good strength matching on the interface. (c) An unelectroded rather than electroded outer surface is beneficial to reducing the stress intensity factor of the interface crack.