Research On Forming Limit Of Square Blanks For Tailor-welded Blanks

With the rapid development of modern industry,people are paying more and more attention to the energy saving and emission reduction of automobiles.Lightweighting of automobiles is an effective measure to achieve energy saving and emission reduction of automobiles.Tailor welded blank forming technology is widely used in the automotive industry as an effective means to achieve this goal.However,compared with the single board,the two sides of the tailor-welded plate have different performances.This difference will cause defects such as wrinkling,cracking,and movement of the weld seam in the forming process of the tailor-welded plate.These defects limit the composition to a certain extent.The application range of welded plates in the automobile manufacturing industry,it is necessary to discuss the influencing factors and forming rules of tailor-welded plates.In this paper,square box shaped parts are used as the research object,and the method of numerical simulation,theoretical analysis and experiment is used to study the drawing process of the same thickness and different thickness tailor-welded blanks,in order to obtain the main factors affecting the drawing process and find the reduction The method of wrinkle cracking and welding seam movement in the small forming process has certain significance for the application of tailored blank forming technology in the automotive industry.In the process of deep drawing of square box shaped pieces of tailor-welded blanks,the blank holder force has a great influence on the forming quality under the condition that the shape of the workpiece is not affected,and this factor is easy to control.In this paper,the finite element method is used to discuss the forming quality of the box-shaped pieces of tailor-welded blanks under different blank holder force loading methods,and a better blank holder force loading method is found.First,the finite element software was used to numerically simulate the drawing process of the square box of tailor-welded plates.The distribution of stress and strain in the main deformation zone of the box-shaped part was analyzed,The mathematical expression of the relationship between the tensile stress of the straight edge zone with the weld,the distance of the weld,and the distance of the flange outer edge is established.Secondly,based on the theory of stress,strain and critical blank holder force in the main deformation zone of the single-plate square box,the stress and strain states of the main deformation zone in the process of drawing the square box of the tailor-welded plate are analyzed and combined with the Comparing the numerical simulation results,it is concluded that the difference between the weld seam and the material thickness has less effect on the deformation of the fillet area and no weld seam passing through the straight edge.And on this basis,the assumption that the area is unchanged during the drawing process is introduced.Established a theoretical analytical formula for the relationship between drawing force and drawing stroke.The self-made tailor-welded square box-shaped block-shaped blank-drawing system was used to verify the drawing process of the 304 stainless steel same-thick-welded blankwelded square box-shaped part.The finite element model can be better The conclusion of the prediction of the drawing law.