Study On Temperature Rise Distribution At The Joint Surface Of Fretting Contact

The joint surface is the most common and main component of CNC machine tools.It plays an important role in transferring motion,load and energy during the operation of the machine tool.At the same time,the continuity of the system is destroyed,which greatly affects the performance of the whole machine.To predict and optimize the overall performance of the machine tool,it is necessary to conduct in-depth research on the interface.At present,most of the research on the joint surface focuses on friction and wear,stiffness and damping,but there are few reports on the temperature rise distribution between the joint surfaces.In fact,in the process of machining parts of CNC machine tools,due to the external load,the machine tool joint surface will continue to produce fretting phenomenon,resulting in a large amount of heat due to mutual friction between the joint surfaces,thus friction and lubrication between the joint surfaces And wear characteristics have a significant impact.Therefore,it is of great theoretical significance to carry out research on the distribution law of temperature rise between joint surfaces for further optimizing and improving the mechanical properties of CNC machine tools.In this paper,based on the relevant theoretical research of the joint surface,by establishing the micro-contact model of the joint surface,the contact characteristics and temperature distribution of the joint surface under different contact conditions are studied,and the contact model is modified to simulate the different fractal parameters.Effect of surface roughness on temperature rise distribution of fretting contact surface.The specific research content and conclusions are as follows:(1)Create a script in Python and import the fractal surface contour coordinates constructed in MATLAB using the Weierstrass-Mandelbrot function into ABAQUS,and use the spline curve to fit the contour coordinates,and use the roughness calculation formula to obtain the roughness under different fractal parameters Degree,so as to construct a two-dimensional cylindrical-plane rough contact model,and carry out dynamic simulation experiments.(2)Based on the rough contact model established in(1),design different tangential and normal loading history.The effects of different normal load forms and normal /tangential load amplitudes,tangential load frequencies,roughness,and contact pair materials on the temperature rise distribution were simulated.According to observations,the contact surface node temperature under different normal load forms shows different oscillating changes.At the same time,it was found that different normal / tangential load amplitudes,tangential load frequencies,roughness,and contact auxiliary materials have a greater effect on temperature rise.(3)The two-dimensional cylindrical / planar contact model is modified so that the fretting contact state is stable to the complete sliding state.Based on the change law of the friction coefficient with the number of fretting cycles and performing simulation tests,the variable friction coefficient,the constant friction coefficient and Influence of surface thermal conversion coefficient on temperature rise distribution of contact surface.The research shows that when the normal / tangential load amplitude is constant,the temperature rise of the contact surface of the variable friction coefficient model is different from the temperature rise of the contact surface of the constant friction coefficient model.The surface heat transfer coefficient is inversely proportional.