| The subframe is an important component of a load-bearing vehicle body,and its main function is to withstand the load on the road surface of the vehicle body,isolate vibration and noise.On the basis of scientific and reasonable welding process analysis,optimizing the welding sequence through thermal deformation analysis during the welding process and numerical solution is beneficial for controlling welding deformation.And improving the consistency of the subframe manufacturing quality and the handling stability of the entire vehicle.Therefore,taking the subframe as the research object,a theoretical model of welding heat conduction was established based on welding technology.The corresponding program was written using MATLAB for the welding process between the subframe lower buckle plate and the bracket,and the welding sequence was optimized using genetic algorithm.Finally,numerical simulation and experimental verification were conducted using the finite element software ANSYS.The main research content is as follows:(1)Welding process analysis of passenger car subframe.Classify common subframes in the market,explain their main functions,select the Yuanbaoliang subframe as the research object,establish its three-dimensional model,and analyze its welding process and welding process characteristics.(2)Theoretical modeling of welding heat conduction.Based on the theories of heat conduction,convection,and radiation during the welding process of the subframe,a transient equation for welding heat conduction was established;The finite element solution process for the thermal elastoplastic equilibrium equation is presented.(3)Optimization of welding sequence for subframe based on genetic algorithm.For the welding process between the sub frame lower gusset plate and the bracket,the thermal deformation height difference of each reference point is taken as the objective function.Based on the finite element method,corresponding programs are written using MATLAB to obtain the numerical solution of welding thermal deformation.On this basis,genetic algorithm is used to find the optimal welding sequence that meets the minimum thermal deformation height difference of each reference point.(4)Finite element numerical simulation and experimental verification.For the welding process between the subframe lower gusset plate and the bracket,simulation data was extracted from ANSYS software,and compared with the height difference data of each welding point in the actual welding of the structural component.The simulation and experimental results showed that the optimal welding sequence obtained by genetic algorithm met the requirement of minimizing the objective function. |
