Research On Simulation Prediction And Optimal Control Of Welding Deformation Of Full Aluminum Body Rear Compartment Assembly

In order to achieve energy saving and emission redu ct ion,the proport ion o f aluminum allo ys used in car bodies is increasing.In recent years,all-aluminum car bodies have been the preferred form o f new energy car bodies.Its body structure is similar to that o f a tradit ional car.The body frame uses alumi num allo y profiles and plates.However,due to the characterist ics of aluminum allo y,the deformat ion and residual stress after welding are large,which affects the accuracy of the body and the energy absorpt ion effect during the co llisio n.Based on the ab ove problems,this art icle takes the all-aluminum body rear floor welding assembly as the research object,and uses Simufact Welding so ftware to perform the rear floor welding assembly mode l welding simulat ion,opt imize the welding sequence and clamping po sit ion,and reduce welding deformat ion.In this paper,the welding experiment and welding procedure qualificat ion test are first carried out.Including the 6061 T6 + 6061 T6 butt jo ints unique to the rear floor welding assembly,welding temperature field t est and welding strain field test.Welding process qualificat ion test was carried out on the five kinds o f welded jo ints o f the rear floor welding assembly to determine the welding process parameters o f the rear floor welding assembly,so as to ensure that the rear cabin assembly was welded without defects.Then,the theory of numerical analysis is summarized,including the mathemat ica l model of welding heat source heat transfer,welding heat source model,mathemat ical model o f stress and strain,and analys is assumpt ion criteria;And use JMat Pro to calculate the thermal performance parameters of the material,and for the 5052-H32 and 6061-T6 aluminum allo y materials in the rear floor welding assembly,the material mechanical performance experiment is carried out to determine the materia l mechanical performance parameters and the material's thermal performance parameters through simulat ion Co mbined with the experiment to ensure that the materia l parameters are accurate.Define the welding boundary condit io ns,and use the appropriate double ellipso idal heat source model parameters to perform MIG welding simulat ion on the 6061-T6 aluminum allo y butt plate,and obtain the temperature field and stress strain field results o f the butt plate welding simulation model.After co mparing with the welding heat cycle curve measurement experiment and the deformat ion measurement experiment,the simulat ion and the experiment are compared,and the reliabilit y of the numerical simulat ion of welding finite element using Simufact Welding so ftware is verified.Finally,the structure o f the rear floor welding assembly is analyzed to determine the key parts that need to contro l the amount o f deformat ion during the welding process;based on the welding jo int process parameters obtained b y the welding process evaluat ion,the rear floor welding assembly is finite element meshed to establish the rear cabin Welding simulat ion model;based on the analysis o f the welding simulat io n results o f the rear floor welding assembly,the welding deformat ion trend and deformat ion results in the welding simulat ion model o f the rear floor welding assembly are obtained;the powerful non-linear calculatio n capabilit y o f the Simufact Welding so ftware is used to analyze the total o f 136 welds in the rear floor welding assembly.Use a simplified model to perform 7 sets of welding sequence opt imizat ion and clamping posit ion optimizat ion so lut ions,find out the opt imal deformat ion control pla n that matches the actual product ion,and provide guidance for the actual product ion;by co mparing with the deformat ion measurement results o f the rear floor welding assembly of the workshop,the simulat ion and The actual error is contro lled within 16%.And successfully predict and contro l the deformation o f the vehicle welding of the vehicle model,adopt suitable welding seam layout and too ling fixture layout scheme,and apply to the product ion o f the vehicle model.