Prediction of the fatigue behaviour of physically vapour deposited coatings in the ball-on-rod rolling contact fatigue test, using an elastic-plastic finite elements method simulation

In the present paper, prediction of the coating fatigue behaviour of coated cylindrical specimens during the ball-on-rod rolling contact fatigue (RCF) test is introduced. The prediction is based on a non-linear finite element method (FEM) simulation, considering analytically the experimentally determined coating fatigue properties. During the RCF test, coated rods are subjected to rolling contact loads, in order to determine the stresses that lead to coating fatigue failure. To accelerate the test, intense contact loads are applied, and plastic deformation of the steel substrate occurs. Owing to this fact, the FEM simulation of the test regards elastic properties for the thin hard physically vapour deposited coating and elastic-plastic properties for the substrate. The attribution of rolling contact conditions is achieved by acting transient normal and tangential pressure distributions. The experimental results are explained considering the calculated stress distributions and existing critical stress values for the fatigue behaviour of the investigated coatings. (C) 1997 Elsevier Science S.A.