Simulating sliding wear with finite element method

Formation of tribochemical layer of ceramics sliding in water and its role for low friction

An extensive survey of the papers pertaining to the thermodynamic approach to tribosystems, particularly using the concept of entropy as a natural time base, is presented with a summary of the important contributions of leading researchers.

https://www.mdpi.com/1099-4300/12/5/1021/pdf

On the Thermodynamics of Friction and Wear―A Review

General solutions for stationary/moving plane heat source problems in manufacturing and tribology

Tribochemical reactions always occur in dynamic and complex contact situations where the mechanical and thermal effects are acting simultaneously, and both are influencing the result This is why different—and sometimes contradictory—assessments of the importance of thermal and mechanical effects on tribochemical reactions are reported in the literature An indicative and interesting example is that of sliding at very low sliding speeds Namely, at low sliding speeds the contact temperatures should be low Therefore, the tribochemical reactions should be a consequence of the broadly prevailing mechanical factors On the other hand, our results show that very high temperatures could occur at the asperity spot-to-spot contacts and that it could be these very high temperatures that are mainly responsible for the tribochemical reactions and various phase transformations, even under very low-speed conditions However, the possibilities for determining the contact temperature and obtaining the reliable evidence are rather limited and their accuracy is suspect In this paper, we discuss various possibilities for determining the contact temperatures and point out the difficulties and uncertainties related to these techniques, particularly when it comes to defining the temperature at the asperity contacts Accordingly, we suggest that several independent techniques for determination of the maximum contact temperature should be used to increase the reliability of the interpretation of the results

Influence of flash temperatures on the tribological behaviour in low-speed sliding: a review

The surface temperature rise for a semi-infinite body due to different moving heat sources is analyzed for the entire range of Peclet number using a Green's function method. Analytical and approximate solutions of maximum and average surface temperatures are obtained for the cases of square uniform, circular uniform, and parabolic heat sources. Considering the heat partition between the two contacting bodies, solutions of interface flash temperature are presented for the general sliding contact case as well as for the case of sliding contact between two moving asperities

Maximum and Average Flash Temperatures in Sliding Contacts

A model is proposed for use is determining the contact surface temperature in dry and boundary lubricated sliding systems. The model uses the concepts of small scale and large scale heat flow restrictions to divide the temperature increase in a sliding contact into two contributions, a nominal surface temperature rise and a local temperature rise. The model is particularly useful in studying the slidingsurface temperature in bodies of finite thickness and in cases when the sliding contact area repeatedly sweeps over the same path on one of the contacting solids. Multiple heat sources within the real area of contact can be included, as can the effects of a cooling and/or lubricating fluid

Contact Surface Temperature Models for Finite Bodies in Dry and Boundary Lubricated Sliding

In this paper, a three-dimensional model of a semi-infinite layered body is used to predict steady-state maximum surface temperature rise at the sliding contact interface for the entire range of Peclet number. A set of semi-empirical solutions for maximum surface temperature problems of sliding layered bodies is obtained by using integral transform, finite element, heuristic and multivariable regression techniques. Two dimensionless parameters, A and Dp, which relate to coating thickness, contact size, sliding speed and thermal properties of both coating and substrate materials, are found to be the critical factors determining the effect of surface film on the surface temperature rise at a sliding contact interface

Temperature Rise at the Sliding Contact Interface for a Coated Semi-Infinite Body

The ability to predict contact surface temperatures in rolling/sliding contacting bodies is important if failure of tribological components is to be avoided. Many works on surface temperature analysis and prediction have been published over the past 75 years or so, but most of the analytical solutions that are readily available do not include such important factors as finite body geometry, surface roughness, or convective cooling. Approaches for addressing these deficiencies are presented in this paper.This paper builds on previous analytical work by the authors and others, and presents models that are based on experimental observations of contact temperatures and factors that affect them. It is shown that the total surface temperature rise above ambient temperature is the sum of nominal temperature rise and flash temperature rise. Models are developed for calculating nominal surface temperature rise for sliding bodies of finite size, including effects of both convection and conduction. Flash temperature models are developed for both single and multiple contacts, as would be found with rough surfaces. Methods are presented that are valid for a variety of geometries and kinematic operating conditions, and techniques are also presented for partitioning the frictional heat between the two contacting surfaces. Examples of the use of the methodology are presented, along with experimental verification of the predictions.

Modeling Sliding Contact Temperatures, Including Effects of Surface Roughness and Convection

This paper describes an experimental study of the sliding behavior of two thermoplastic polymers, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWPE), in oscillatory sliding contact. Sliding surface temperatures were measured with the aid of miniature thin film surface thermocouples, and the results were related to friction and wear behavior. The temperature measurements were also correlated with predictions of a recently-developed surface temperature model for finite bodies in oscillatory sliding contact. The experimental results showed that the contact temperature rise is dominated by a steady state nominal temperature rise, upon which is superimposed a cyclic local temperature rise. When the sliding speed and normal load were high, the measured peak surface temperature reached a ceiling value for the thermoplastic materials. The critical temperatures for PMMA was the temperature at which it softened while under compressive stress, approximately 30-35°C below the melting temperature of the material, whereas UHMWPE's critical temperature was found to be very close to its melting temperature. At the critical temperature, the wear rate drastically increased and there was a large increase in the real area of contact, but there was not a large change in friction coefficient. The increase in contact area caused a decrease in frictional heat flux, thus limiting the surface temperature rise. Owing to the large changes in wear and contact area which occur at the critical surface temperature of thermoplastic polymers, conditions which would result in such temperatures must be avoided in sliding components using those materials. In-situ surface temperature sensors could help insure that the sliding temperatures don't reach the critical values.

Xuefeng Tian

Papers

Maximum and Average Flash Temperatures in Sliding Contacts

Contact Surface Temperature Models for Finite Bodies in Dry and Boundary Lubricated Sliding

Temperature Rise at the Sliding Contact Interface for a Coated Semi-Infinite Body

Modeling Sliding Contact Temperatures, Including Effects of Surface Roughness and Convection

The Effect of Interfacial Temperature on Friction and Wear of Thermoplastics in the Thermal Control Regime