A Rough Surface Contact Model Considering Microscale Strain-Hardening Effects

The strain-hardening effect exerts significant influence on microscale surface contact behavior. This study identifies two critical limitations in existing rough surface contact analyses: insufficient consideration of material strain-hardening effects and discontinuities in asperity contact pressure distributions. By integrating microscale strain-hardening theory with finite element methodology, this paper establishes quantitative relationships between key parameters, including strain-hardening coefficients, material yield strength, and asperity plastic deformation limits. An analytical elastoplastic contact model incorporating strain-hardening effects is developed for individual asperities, complemented by a statistical summation approach for multiscale rough surface characterization. Model validation demonstrates (1) the contact pressure curve for the proposed single micro-asperity model is smooth and continuous. Under varying strain-hardening parameters, the maximum error between the model’s average pressure calculation and the finite element simulation results is 7.03%; (2) the experimental results of rough surface contact align closely with the predicted average contact pressure from the proposed model, with a maximum error of 9.73%, confirming the accuracy of the model; (3) ignoring strain hardening in the analysis, based on the measured surface morphology and operating conditions of the workpiece, leads to an underestimation of the contact pressure by 47.63%. This error increases further with the rise in strain-hardening effects. This paper presents a novel rough surface contact model that incorporates microscale strain-hardening effects, offering a more accurate method for analyzing practical contact problems.

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