Fretting contact of FGPM coating-substrate system under cyclic torque based on laminated model

Fretting contact problem of functionally graded piezoelectric material (FGPM) coating bonded to the piezoelectric substrate under the rigid conducting indenter is considered. The laminated model is used to simulate the nonhomogeneous piezoelectric coating with electromechanical properties varying arbitrarily along the thickness direction. The spherical indenter is applied under the normal force and cyclic torque to generate the slip and stick region on the surface of FGPM coating. The problem was described mathematically according to the singular integral equations which are transferred to a system of linear equations by employing the numerical method. The stress distribution, the stick/slip region, torsion angle, surface displacement, and electrical displacement are obtained for different gradient value of FGPM coating under the cyclic torque loading. The present results will provide the theoretical basis for the design to FGPM coating.