Progress in contact mechanics of a type of functional gradient materials

In regard to a type of materials with gradient varying Young's modulus in the depth direction, considering the effects of interfacial friction, fretting and adhesion, the influences of finite scale of materials, the varying gradient law, thickness of gradient coating, thermo-friction of interface and the shape of punch on the surface contact features are summarized. The performance of resistance to wear of the gradient material surface is mainly analyzed according to the interfacial contact stresses in different contact models. Unsolved problems and prospects of future study on contact mechanics of functional gradient materials are suggested finally.