| Friction heat is an inevitable phenomenon when the metal is in contact with each other,which is an important part of tribology.Friction heat has an influence on the performance of materials and wear process,which affects mechanical’s performance and life.Therefore,it is very important to study the thermal effect of metal sliding friction process for tribology design and engineering application.Based on the sliding friction experiment,the finite volume method is applied to the friction heat,and the friction heat parameters on the microscopic scale are studied by molecular dynamics model.Finally,the parameters of the microscopic scale are extended to Macro scale by G-W contact statistical model.Designing and building the experimental bench of the friction heat,the coppercooper rotating friction pair was taken as the research object.The temperature of the friction heat was measured by the temperature measuring device,and the friction coefficient was calculated by the torque power meter.The effect of different factors on the friction thermal effect was studied.In the range of 200 r / min-600 r / min and the load is in the range of 3.7kg-7.7kg,the temperature rise and the friction coefficient increase with the increase of the speed and load.The thermal effects of copper-aluminum friction pairs and copper-Q235 friction pairs were studied.With the greater the coefficient of friction,the more heat was generated and the more heat flow into the larger thermal conductivity of the material.Based on the theory of friction heat and the finite volume method,the complex friction heat production process was simplified to the numerical simulation of the thermal conductivity that the planar circular heat source applies the thermal conductor.Establishing a three-dimensional finite volume models,and determining the boundary conditions,the temperature field distribution of friction heat was simulated when coppercopper friction at a speed of 600r/min and a load of 3.7kg.The results of the simulation were in good agreement with the experimental results.The variation law of the simulated temperature field was analyzed with the speed of 200r/min-600r/min and the load of 3.7kg-7.7kg,which is the same trend as the experimental results.The reason of the deviation between the simulation result and the experimental result is explained.The molecular dynamics model of the dry sliding copper asperities was established on the microscopic scale.The friction force,the normal force,the effective friction coefficient,the flash temperature and the energy were analyzed by LAMMPS software.Based on the Greenwood-Williamson contact statistical model,with establishing a sliding friction model,the thermal parameters of the microscopic scale were extended to the macroscopic scale and the accuracy is verified comparing with the measured values during the experiment. |
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