FE Simulation Research Of Temperature Field For Friction And Wear With Electric Current

Friction and wear with electric current is a problem in tribology under special working condition, and is a process of electric current contact. The main kinds of thermal generated in the process are friction thermal, contact resistor thermal and arc thermal, these thermal will result in temperature increment of the friction pairs.Finite element model for aluminum-stainless steel composite conductor rail/collector shoe under the coupling of contact resistor-friction thermal was established by ANSYS. Temperature field of the friction pairs under electric current was simulated; temperature field distribution and the maximum temperature changing under different electric current, relative sliding velocity and normal pressure were studied.By analyzing coupling the temperature field distribution and the changing principles of maximum coupled temperature for the three materials, these conclusions were drawn as follow:(1) In the coupling process, the highest coupled temperature may in the surface zone of the collector shoe and around the electric current contact point or in the contact center line of mechanical friction, the temperature distribution expands around the maximum temperature zone in descending tendency and temperature gradient is becoming smaller;(2) While the other parameters keep unchanging, the maximum coupled temperature rises with the increasing of electric current for metal impregnation carbon and copper-based powder metallurgy; as for copper, the principles for which the maximum coupled temperature changes with electric current keep the same as the other two materials, and there is a particular case: when relative sliding velocity and normal pressure is relatively large, the maximum coupled temperature keeps unchanging at first and then rise with the increasing of electric current;(3) As for the same material, with the unchanging electric current, when normal pressure is very small, the maximum coupled temperature decreases with the increasing of relative sliding velocity; when normal pressure is relatively small, the maximum coupled temperature decreases with the increasing of relative sliding velocity at first and then keeps constant; when normal pressure is relatively large, maximum coupled temperature keeps constant with the increasing of relative sliding velocity and with normal pressure becomes larger, the constant value becomes larger;(4) As for metal impregnation carbon and copper-based powder metallurgy, with normal pressure sampling 60～270N, as the relative sliding velocity keeps unchanging, the maximum coupled temperature decrease at first and then rise with the increasing of normal pressure when electric current is relatively small, namely showing a trend of"U"; the maximum coupled temperature decrease with the increasing of normal pressure when electric current is relatively large;(5) As for copper, with normal pressure sampling 60～270N,as the relative sliding velocity keeps as a relatively large constant, the maximum coupled temperature increasing constantly with the increasing of normal pressure when electric current is relatively small, the maximum coupled temperature shows a trend of"U"with the increasing of normal pressure when electric current is relatively large; as the relative sliding velocity keeps as a relatively small constant, the maximum coupled temperature show a trend of"U"with the increasing of normal pressure when electric current is relatively small; the maximum coupled temperature shows the same principles as the other two materials under the same condition when electric current is relatively large;(6) As for copper, with normal pressure sampling 30～270N, as the relative sliding velocity keeps as a relatively large constant, the maximum coupled temperature shows a trend of"U"with the increasing of normal pressure when electric current is relatively large; In the other condition, the maximum coupled temperature shows similar principles as the other two materials under the same condition.By comparing and analyzing the three maximum temperatures of the three materials, these conclusions were drawn as below:(1) In the coupling process, the maximum coupled temperature may present a minimum value with the increasing of normal pressure, and a"critical normal pressure"which can be used as a reference for choosing material is corresponding to the value.(2) As the relative displacement keeps as a constant, the maximum coupled temperature shows a trend of"U"with the increasing of normal pressure when electric current is relatively small the and the"critical normal pressure"which is influenced by electric current, relative sliding velocity and material properties present at different time;(3) As the relative displacement keeps as a constant, thermal deformation may happen for metal impregnation carbon and copper-based powder metallurgy when electric current is relatively large, and the relative sliding velocity is relatively small and the sampling value for normal pressure is 30N.