Variational approach to the analysis of steady‐state thermo‐elastic wear regimes

Abstract

SUMMARYA transient wear process on frictional interface of two thermo-elastic bodies in a relative steady sliding motion induces shape evolution of contact interface and tends to a steady state for which the wear process occurs at fixed contact stress and strain distribution. The temperature field generated by frictional and wear dissipation on the contact surface is assumed to reach a steady state. This state is assumed to correspond to minimum of the wear dissipation power and the temperature field corresponds to maximum of the heat entropy production. The stationarity conditions of the response functionals provide the contact pressure distribution and the corresponding temperature field. The present approach extends the authors previous analyses of optimal or steady-state contact shapes by accounting for coupled wear and thermal distortion effects.The wear rule is assumed as a non-linear relation of wear rate to shear stress and relative sliding velocity. The analysis of disk and drum brakes is presented with account for thermal distortion effect. It is shown that the contact shape in a steady thermo-elastic state essentially differs from that specified for mechanical loading with neglect of thermal effects. The thermal instability regimes are not considered in the paper.

Analysis of steady wear processes for periodic sliding

“…For cases of monotonic sliding motion the minimization of the wear dissipation power provided the contact pressure distribution and rigid body wear velocities directly without time integration of the wear rule until the steady state is reached, cf. [1,2,3,4]. (The steady state is reached when the contact stress is fixed with respect to the moving contact domain and the rigid body wear velocity is constant in time.…”

“…Next, this approach was extended in [2] by the authors of previous analysis to specification of steady-state contact shapes with account for coupled wear and thermal distortion effects. The wear rule was assumed as a non-linear relation of wear rate to shear stress and relative sliding velocity.…”

“…Paper [13] was aimed at extending the results of previous analyses [1,2,3,4] of steady state conditions to cases of periodic sliding of contacting bodies, assuming the existence of cyclic steady state conditions. In the time integration it was be assumed that contact pressure distribution is fixed during the semi-cycle and varies discontinuously during sliding reversal in consecutive semi-cycles.…”

Contact Thermal Analysis and Wear Simulation of a Brake Block

“…However, the processes in railway brake systems are quite complex. There are many studies about the steadystate friction of such applications, some of them considering even the wear and the thermal effects [3][4][5][6]; yet the real-life braking is typically a transient phenomenon, the vehicle is usually stopped in seconds or in a few minutes. Since most of the kinetic energy of the train is transferred to heat by the friction between the wheels and the brake blocks, a big amount of heat is developing in a short time.…”

Wear simulation of a reciprocating seal by global remeshing

“…Fillot et al in [2] applied the method of discrete elements, which made it possible to model the effects of wear debris as third body of the tribological system. Páczelt and Mróz in [3] showed a variational approach for wear analysis. However, the most popular numerical technique in engineering is the finite element method (FEM).…”