Thermo-force Coupling Analysis Of Torsional Fretting Based On Frictional Heat Generation

Torsional fretting is one of the four basic fretting modes.Torsional fretting exists in a large number of actual engineering projects,which amplitude of motion is very small.The impact of torsionalfretting is hardly to observe.It cann't be ignored that wear and fatigue damage caused by torsional frettinglead parts to wear and failure.Torsional fretting research started late.There are few reports about torsional fretting,which reports focuses on experimental researchmainly recent years.This paper focuses on the influence of frictional heat on torsional fretting.The contact mechanics behavior of two aluminum alloy materials is studied,that based on the finite element method.The heat source model related to the stress field is embededby the user subroutine,and the thermal-mechanical coupling torsional fretting prediction model is established.The numerical analysis of fretting temperature field and stress field is carried outto explore the corresponding material response behavior.The main research work is as follows:1.Torsional fretting numerical model is established by using the spherical-plane contact geometry based on finite element method.The contact pressure and contact radius of the Hertz theoretical solution are compared with the numerical solution,andthe results of the two kinds are consistent well.The correctness of the finite element numerical model and the feasibility of the analysis are verified.2.The numerical simulation analysis of torsional fretting behavior of 7050 aluminum alloy and 2024 aluminum alloy are carried out,and the influence of key fretting parameters on stress and strain distribution and evolution are studied.The results show that the distribution and variation of von Mises stress,shear traction and plastic strain in different operating phases are obviously different,which results have some correspondence with the wear and damage laws of experimental phenomena.3.The thermal coupling effect of torsional fretting is researched based on the frictional heat generation.The distribution and changes of temperature rise of the surface and subsurface are analyzed,and the effect of temperature rise on stress and strain distribution in high fretting cycle is analyzed.The influence of key fretting factors on the distribution and change of temperature rise is summarized.The results show that the temperature rise has different distribution and variation rules in the different operating phases of the torsional fretting,and the temperature risehas a significant influence on the stress and strain,therefore,the frictional heat is an important influencing factor in the fretting damage,and the friction heat is of great significance to reveal the mechanism of torsional fretting damage.4.The torsional fretting damage characteristics of 7050 aluminum alloy and 2024 aluminum alloy are compared and analyzed.The difference between the different fretting parameters on stress and strain and temperature rise of the two materials are studied.The material response behavior is explored,which lay the theoretical foundation for the selection of materials for tornional fretting friction pair.