General results for loading and unloading rough elasto-plastic interfaces

Abstract

From the classical model of Bowden and Tabor it is known that metallic materials make contact only on a small fraction of the nominal contact area, where pressure is so high that plastic deformations is likely. While the contact area has been extensively studied within this context, indentation has attracted less attention. In this work we thus characterize the relationship between load and indentation for nominally flat Gaussian surfaces, finding universal trends which persist when either the level of plasticity or the indentation depth change. We study both loading and unloading trends. Also, we discuss the height distribution of the surfaces resulting from cumulative plastic deformation. For all this cases, we obtain very simple and closed form analytical fittings that allow a convenient and general use of the results here presented. Finally, we compare the results obtained from the model, based on Boundary Element model and perfect plasticity, with experimental result, to justify the validity of its use.

FPR received funding support from the Spanish Ministry of Science and Innovation through grant PID2021-407 126614OB-I00 and from the research group RIIS-UPC. XML received funding from the National Natural Science Foundation of China (Grant No. 12302126). MC received no funding.

Peer Reviewed

Postprint (published version)