Research on loading and unloading characteristics of joint surfaces based on ellipsoidal micro-asperities
LIU Yulong
LAN Guosheng
SONG Jianguo
LI Yong
LIAO Juntao
KANG Depeng
Abstract：[Objective]To address the inaccurate simulation of joint surface contact characteristics caused by the non-uniform geometric shapes of micro-asperities,the mechanical responses and deformation mechanisms of ellipsoidal micro-asperities with varying eccentricities during the normal loading and unloading processes are investigated.[Methods]Firstly,based on the three-dimensional anisotropic fractal theory and Hertzian contact mechanics,a theoretical loading-unloading contact model for ellipsoidal micro-asperities was established.Secondly,numerical simulations were performed under two distinct boundary scenarios:a constant tip curvature radius and a dynamic tip curvature radius varying with the contact area.Finally,test data from a gray cast iron grinding joint surface were introduced to validate the models,and the influences of fractal dimension and fractal roughness on the contact load were analyzed.[Results]The comparative analysis demonstrates that the micro-asperities on rough surfaces are composed of multi-shaped geometries rather than a single profile.For the improved model where the curvature radius varies dynamically with the contact area,the simulated curves exhibit excellent agreement with the test data,restricting errors to within 14％during the loading stage and 22％during the unloading stage.In the late elastoplastic stage,the test trajectory shifts toward the ellipsoidal model with eccentricities between 0.5 and 0.7,confirming the higher bi-directional accuracy and physical feasibility of the improved model.
Keywords：Joint surfaceEllipsoidal micro-asperityLoading and unloadingRadius of curvatureFractal theory
Publication Date：2026-07-31
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：10( 156-165 )