Numerical Study On Torsional Fretting Wear Of Rough Surface

Torsional fretting wear is caused by cyclic reciprocating motion with a small amplitude of angular displacement between contact surfaces under the action of alternating loads.Torsion fretting is widely present in fastening components such as vehicles,aviation industry,human joints,bearing balls and so on.It is not easy to detect at the initial stage of damage,but it is extremely harmful.At present,tangential fretting and torsional fretting of smooth surfaces have received widespread attention,but there are few studies considering the torsional fretting of rough surfaces.In actual construction machinery,the contact surface is not absolutely smooth,but is composed of a large number of micro-protrusions.The actual contact only occurs on the higher micro-protrusions,and its contact mechanical behavior is completely different from that of smooth surfaces.Considering the influence of rough surface profile on the mechanical behavior of torsional fretting,it can not only promote the understanding of the damage mechanism of torsional fretting,but also design the initial surface matching and wear protection of close-fitting parts in actual construction machinery.Has guiding significance.Based on the three-dimensional W-M fractal function,SOLIDWORKS is used to establish a three-dimensional rough surface.At the same time,the ABAQUS user subroutine UMESHMOTION is used to introduce the energy wear criterion,and a three-dimensional ballrough surface contact is established.The influence of roughness on the friction and wear process of torsional fretting and the distribution of temperature rise.The main research contents are as follows:1.Firstly,the non-dimensional contact area analytical solution of the G-W model is used to verify the rationality of the rough surface model.At the same time,it is compared with the experimental wear results to verify the accuracy and effectiveness of the numerical model for the torsional fretting wear prediction.2.Based on the energy wear criteria,with the adaptive mesh technology in ABAQUS,the finite element wear results of the corresponding areas in the calculation of the experimental wear conditions,and the wear profiles are in good agreement with the experimental wear profiles;based on the above verified wear conditions,Change the loading conditions,carry out the numerical simulation analysis of the torsional fretting wear of 7050 aluminum alloy,and study the influence of the main influencing factors on the mechanical behavior of the rough contact surface wear,the wear evolution,and the degree of wear.The results show that:in each operating area,the friction shear stress,relative slip distance,wear volume,and frictional dissipation energy values and distributions all show different changes;in the same operating area,under different loading conditions,the above result variables are The law of change is still different,but basically corresponds to the experimental results and theoretical results.3.Write W-M function through MATLAB to realize parametric modeling and establish finite element models of different roughness surfaces.The stress singularities caused by different roughnesses are different and have a greater impact on the contact mechanical behavior.Therefore,it is an accurate prediction The evolution of torsional fretting wear of different surface geometries is particularly important to explore the influence of different roughness on wear.The results show that: different indicates that the roughness has a significant effect on the transition critical value between the fretting operation regions;with the change of the surface roughness,the mechanical behaviors such as friction shear stress and plastic strain between the contact surfaces also change significantly;in addition,In each operating area,different roughness has different influences on wear volume,friction dissipation energy,friction activation energy,wear rate and other wear degree characterization.4.Establish a thermal-mechanical coupling prediction model for the torsional fretting of the rough surface,analyze the temperature rise changes under different initial roughness and load conditions and the influence of the temperature rise on the stress distribution,and reveal the temperature rise distribution of the rough surface in the torsional fretting wear And the influence of temperature rise on microdynamic behavior and wear behavior.