The Elastic—Plastic Contact of Rough Surfaces and its Relevance in the Study of Wear

Abstract

In a recent paper it was shown that the limit of elastic behaviour of rough surfaces could be defined by a unique relationship between the plasticity index and the nominal pressure. Specific experimental evidence suggested that the best theoretical model was one when the asperity height probability distribution was assumed Gaussian with a truncation of 3 σ. This paper extends this argument by showing that for a given ratio of plastic-elastic area of real contact, similar unique relations exist between the plasticity index and nominal pressure. It is assumed that the maximum non-dimensional elastic deformation is given by the inverse of the square of the plasticity index, and this is supported by experimental results. It is also shown that the model proposed is in error at higher pressures, due to the interaction of the deformations of adjacent asperities.