Plastic yield inception of an indented coated flat and comparison with a flattened coated sphere

The yield inception of a deformable hard coated half space indented by a rigid sphere is studied. The effect of coating thickness, sphere radius and material properties of both the coating and substrate on the critical contact parameters at yield inception is investigated. Dimensionless empirical expressions for the critical load, critical contact area and critical interference are derived as functions of a dimensionless hard coating parameter. Three different locations of the yield inception of the coated system are observed. A comparison is made with the case of a flattened coated sphere.