| The failure of electronic components in pure electric vehicle is mainly caused by high temperature,so excellent cooling system is the guarantee of stable,safe and reliable operation of the whole vehicle and electric drive system at normal temperature.Aluminum alloy liquid cooling radiator has ideal heat dissipation effect on electronic equipment of electric vehicle controller.The welding methods of aluminum alloy radiator parts are manual TIG welding,automatic TIG welding and MIG welding.Friction stir welding(FSW)has the characteristics of high quality of welded joint,small deformation and not easy to produce defects,and has been developed rapidly in recent years.However,because the volume of aluminum alloy liquid cooling radiator is relatively small,the residual stress will be produced in the weld bead and inlet of aluminum alloy liquid cooling radiator by FSW method.Therefore,it is necessary to study the FSW technology for aluminum alloy liquid cooling radiator of pure electric vehicle controller,to explore the variation of temperature field and residual stress of weld during welding,and to provide support for its FSW welding.In this paper,the liquid-cooled radiator plate of a certain type of electric vehicle controller is taken as the research object.Based on the exploration of the basic theory of heat transfer,the FSW full thermodynamic coupling model of liquid-cooled radiator is redeveloped by using the ABAQUS software,and the moving heat source model of the stirring head is established.Furthermore,the temperature distribution characteristics of the cooling plate in welding process under different process parameters were explored,and the influence of different parameters on the residual stress at the weld joint and the water inlet was studied,which provided a reference for the research on the temperature field and residual stress of the FSW welding of the liquid cooling plate.The main research contents are as follows:(1)On the basis of the theory of heat transfer,the complete thermodynamic coupling model of liquid cooling radiator under FSW process was developed by using finite element software ABAQUS.The moving heat source model of stirrer head was established.The welding temperature field of liquid cooling radiator made of 6061-T6 aluminum alloy was simulated.According to the relevant simulation and experiment,the rationality of the model is checked,and the temperature field distribution at the welding joint was studied under different rotational speed,welding speed and stirring needle pressure,and the corresponding temperature field variation law was obtained.(2)The residual state of 6061T6 aluminum alloy liquid cooling radiator was simulated and analyzed,and the rationality and accuracy of the model were checked according to relevant studies.Different parameters of welding process were simulated,and the variation characteristics of weld residual stress under different stirring head rotation speed,welding speed and stirring needle pressure were studied.(3)On the basis of meeting the welding temperature requirement of 6061-T6 aluminum alloy liquid cooling plate under FSW process,the distribution characteristics of residual stress in weld seam and inlet under different technological parameters were explored.Through numerical analysis,two groups of optimized FSW parameters were obtained,as follows: 1)when the pressure,rotation rate and welding speed are 8000 N,600r/min and 1 mm/s respectively,the Mise residual stress value of weld is 95.5 Mpa,the longitudinal and transverse residual stresses of water inlet channel are-29.5 Mpa and-23.3Mpa.2)when the pressure,rotation rate and welding speed are 6000 N,800 r/min and 1mm/s respectively,the Mise residual stress value of weld is 90.6 Mpa,the longitudinal and transverse residual stresses of water inlet are-23.6 Mpa and-27.5 Mpa respectively.The research in paper provided reference for the study of FSW of aluminum alloy liquid cooled radiator plate. |
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