Research On Optimization Method Of BIW Spot Welding Based On Experimental Design And Modeling

In addition to introducing new process methods,automobile enterprises will introduce new materials in the trial production of new body in white.At present,high-strength steel plate has become the most popular new material for automobile manufacturers because of its obvious cost advantage and excellent molding technology.More high-strength steel plates are used to make the spot welding ratio of three-layer plate lap joint higher than before,up to 1 / 2 of the whole vehicle.Compared with the two-layer spot welding,the three-layer lap joint is more prone to welding quality problems such as too small nugget,nugget offset,burn through,spatter and so on.It is very important to ensure the strength and quality of the welding spot of the three-layer steel plate to improve the body quality.In the actual trial production of body welding,the test welding method of sheet metal is used to adjust the welding parameters.Due to different materials and material thicknesses,there are usually 30 to 50 combinations for three-layer plate lapping of the whole vehicle.Each combination needs to prepare more than 10 groups of sheets for spot welding parameter debugging.The whole body needs to do 300 to 500 groups of three-layer steel plate spot welding test,which can be imagined for the waste of materials and working hours.Aiming at this problem,this paper studies the optimization method of body spot welding combining with experimental design and finite element analysis.In this paper,the optimization process of spot welding parameters of a three-layer steel plate(including two kinds of high-strength steel plates)is studiedThe first chapter not only introduces the current situation of the research,but also makes the overall arrangement of the research work;In the second chapter,the possible influencing factors of spot welding of three-layer steel plate are analyzed,and these influencing factors are selected according to their controllability and influence degree,from which the welding current,welding time and electrode pressure are determined as the following test factors;In the third chapter,according to the principle of reducing the number of tests,uniform design method is used to reduce the number of test points,and regression analysis is carried out on the test results to get the regression equation of spot welding parameters.In the fourth chapter,the finite element model is established,and the lap joint of three-layer steel plate on the side wall of a car is simulated.The simulation results are compared with the nugget size data of the third chapter,and the model is verified to be effective.The systematic method of spot welding parameter optimization can be obtained.In this study,uniform design analysis and finite element analysis are combined to simplify the process of setting resistance spot welding process parameters and effectively reduce the time and material consumption of setting coefficient.On the optimization of welding parametersIn view of the above engineering and technical problems,combined with the actual production and technological conditions of the enterprise,the paper studies the main factors influencing the welding quality of the three-layer steel plate lap joint in the process of resistance spot welding by means of experimental analysis and theoretical research,establishes the three-layer steel plate resistance spot welding finite element model and carries out simulation and test verification based on the test results,so as to reveal the three-layer steel plate Key points of nugget quality control.Combined with the actual production,the existing process is optimized to improve the nugget offset,spatter,surface quality and other problems of the three-layer steel plate welding spot,improve the quality of the body welding spot,and simplify the process of welding parameter formulation.In this paper,the design and optimization of resistance spot welding parameters of BIW are completed based on the production process and engineering technology.The research results show that the method of combining uniform design analysis and finite element analysis can be used to simplify the process parameter setting method of resistance spot welding,reduce the defects of three-layer steel plate solder joints,and improve the quality of body solder joints and surface quality significantly.