CHARACTERIZATION AND MODELING OF SUBSURFACE DAMAGEIN A 356 ALUMINUM ALLOY SUBJECTED TO MULTIPLE ASPERITYSLIDING CONTACTS

摘要

In certain tribological applications of aluminum, sliding surfaces involves large plasticdeformation and subsurface damage, even under light loads. In the subsurface layers adjacent tothe contact surfaces, the competition between the plastic strain, which enhances void growth,and the hydrostatic pressure, which suppresses it, is considered to be responsible for thegeneration of a damage gradient. On the basis of this concept, debris formation can be attributedto the delamination of the subsurface layers at a certain depth where the damage accumulationrate is highest. Numerical analyses are necessary to determine the magnitude and distribution ofthe hydrostatic pressure and hence determine the subsurface damage gradient under variousloading conditions. Accordingly, the main objective of this study is to build a finite elementmodel to analyze subsurface deformation that occurs in the aluminum alloys subjected tosliding contact. An Eulerian model capable of accounting for large strain accumulation undermultiple asperity contacts was employed. The effects of friction, normal load and slidingvelocity on the multiple asperity contacts were investigated. The numerical results werecompared and validated with a limited number of normal contact experiments.