The Fundamental Regularities of the Evolution of Elastic Vortices Generated in the Surface Layers of Solids under Tangential Contact Loading

Abstract

Abstract:Conventionally discussed dynamic mechanisms of elastic strain energy redistribution in near-contact surface regions include P and S elastic wave pulses radiating from the contact surface. At the same time, the elastic strain energy can be transferred by localized vortex-like elastic waves (Rayleigh, Love, Stoneley wave, and so on). In the paper, we numerically studied the main features of the formation and propagation of localized vortex-like waves in the surface layers under the contact zone. The study was done using the numerical method of movable cellular automata. We showed that the initial phase of dynamic contact interaction with a nonzero tangential component of contact velocity is accompanied by the formation of a so-called elastic vortex. The elastic vortex is a fully dynamic object, which is characterized by shear stress concentration and propagates at the shear wave speed. We first revealed the ability of the elastic vortex to propagate toward the bulk of the material and transfer elastic strain energy deep into the surface layer in a localized manner. We analyzed the dependence of the direction of vortex propagation on the tangential contact velocity, contact pressure and Young's modulus of the material. The results of the study are important for better understanding the dynamic mechanisms contributing to inelastic strain accumulation or gradual degradation of surface layers.

3D simulation of dry friction of metal-based composites

“…For isotropic material the volume-dependent part of the total force can be written as follows [13][14][15]:…”

“…A detailed description of the inter-automata forces and torques, as well as plastic flow and transitions from bonded state to unbonded one and vice versa, can be found elsewhere [13,15]. Here we just note, that to describe elastoplastic flow of the material, it was proposed to use the plastic flow theory (namely von Mises model) by adapting the algorithm of Wilkins in the MCA method [15,16].…”

“…In [10] it was shown that MCA method allowed studying numerically so-called quasi-fluid nano-layer between rubbing bodies. That and other MCA simulation of friction in contact patch were conducted in 2D statement [11][12][13]. 3D simulations of contact problems have been mainly devoted to indentation and scratching [14,16,17], as well as friction stir welding [14].…”

“…Most of MCA applications for sliding friction are made in 2D statement [10][11][12][13], the aim of the work is to develop a 3D numerical model of the sliding friction of steel samples at the scale of contact patch and study on its basis the influence of carbon nanoinclusions on the sliding friction.…”