Model for Elastic–Plastic Contact Between Rough Surfaces

Abstract

This paper studies elastic–plastic contact between Greenwood–Williamson (GW) rough surfaces, on which there are many asperities with the same radius whose height obeys the Gaussian distribution. A new plasticity index is defined as the ratio of the standard deviation of the height of asperities on the rough surface to the single-asperity critical displacement (the transition point from the elastic to the elastic-fully plastic deformation regime), which is linearly proportional to the GW plasticity index to the power of 2. The equations for the load/area–separation relationship of rough surfaces are presented based on Wang and Wang's smooth model of singe-asperity elastic–plastic contact, which is an improvement of the Kogut–Etsion (KE) empirical model based on finite element analysis (FEA) data. The load/area–separation relationship can be described by empirical Gaussian functions. The load–area relationship of rough surfaces is approximately linear. The average pressure is only function of the new plasticity index. According to Wang and Wang's conclusion that Etsion et al. single-asperity elastic–plastic loading (EPL) index is approximately equal to the ratio of the single-asperity residual plastic contact displacement to the single-asperity total elastic–plastic contact displacement, the equations for the relationship between Kadin et al. modified plasticity index (MPI) and separation of rough surfaces are also presented. In addition, the MPI is approximately linearly proportional to the separation between rough surfaces for a given new plasticity index ranging from 5 to 30. When the new plasticity index is smaller than 5, due to the large proportion of the elastic deformation in the total deformation, the MPI slightly deviate from linearity.

A New Approach for the Relationship Between the Contact Stiffness and the Interference of Journal and Bearing Shrink-Fitted

“…They compared the computational results of these different contact models. Based on the GW model, Wang Z [21] obtained an EPL (elasto-plastic loading index) for a single micro-convexity, which is approximately equal to the ratio of the residual plastic contact displacement of a single protrusion to its total elasto-plastic contact displacement. Chen Z [22] pro-posed an elastoplastic coated rough surface contact based on GW's statistical model and investigated the effect of the surface roughness of coating substrate on the coating surface, contact deformation pattern and contact behavior.…”

Fractal Model of Contact Thermal Stiffness

“…The direct relationship between the actual contact area, contact load force, contact stiffness, and surface deformation in the elastic, plastic, and elastic-plastic stages of rough surface asperity have been studied. However, these contributions are based on the static characteristics of pure mechanical joints [8][9][10][11][12][13][14][15][16][17][18][19][20]. Based on the fractal theory of rough surface and measurement experiments, Kogut and Komvopoulosa [21] yield insight into the influence of rough surface morphology, current, and contact force on electrical contact thermal resistance.…”

Study on the Relationship Between the Contact Stiffness of Micro-Convex Body over the Full Contact Domain and the Macroscopic Interference Value

“…The elastic-plastic interaction of micro-convex body contact involving a rough surface is crucial for many engineering applications; in recent years, research on the subject of modeling elastic-plastic micro-convex body contact remained popular [10]. Müser et al generated a rough surface using FEM simulations, and invited various research institutions worldwide to apply their respective research contact theories and models to model contact on this rough surface, to compare the computational effects of different contact models [11] Wang Z [12] took the GW's single micro-convex body elastoplastic loading (EPL) index as a basis and obtained the conclusion that the ratio of residual plastic contact displacement of the single convex body is approximately equal to the total elastoplastic contact displacement of the single convex body. Chen Z [13] proposed an elastoplastic coated rough surface contact based on GW's statistical model and investigated the effect of the surface roughness of coating substrate on the coating surface, contact deformation pattern and contact behavior.…”