A numerical method for analysis of extended rough wavy surfaces in contact

Topographies of engineering surfaces normally have both random and periodic components, designated as surface roughness and waviness. True contacts between two such surfaces develop between the peaks, or asperities, on each surface. The waviness of the surfaces determines the spatial distribution of true contacts over the interface such that true contacts on wavy surfaces occur at and near the wave crests. This paper presents a computational method for analysis of contact between two rough wavy surfaces for which the nominal contact area may be arbitrarily large. The model used here combines local deflection of a contact point due only to the force acting on it with the non-local deflection of the same point due to forces at all other points of the surfaces. Using a three-stage loop similar to multi-level substructuring in finite element analysis and a nested iterative approach, the proposed method calculates the true contact area for a large number of asperity contacts, O (10(3)). Results of calculations show how contact parameters change with external load and also demonstrate the validity of the method.