Research On Drawing Forming Of Calindrical Parts Of Tailor Welded Blanks

In recent years, the automotive lightweighting is the important measures to deal with the problems of environmental and energy, such as governments, academia and automobile industry, and the forming technology of tailor-welded blanks(TWBs) is the key technology to realize lightweight of automobiles. But in the process of TWBs, due to the presence of the weld line and the strength difference between the materials on both sides of the weld line, some problems often arise in the deep drawing of TWBs, such as rupture, wrinkling and weld-line movement and so on, these shortcomings limit the forming technology of TWBs to a wide range of applications. Moreover, the research for the axisymmetric parts is very complicated, therefore, it is of great significance to study the drawing forming of tailor welded blanks based on the cylindrical part.In the process of theoretical analysis of a cylindrical parts of TWBs, based on certain assumptions, the stress state in the weld line of the integral form is analyzed, and the approximate expression of the main deformation zone stress, the drawing force, wrinkling and breaking critical boundary force is obtained. With the influence can be found in the formula of wrinkle the main factors of instability and rupture instability with the thickness of the sheet metal radius, BHF(blank hold force), thickness ratio, concave die and punch round radius and friction coefficient, etc.In the process of simulation analysis of a cylindrical parts of TWBs, considering the defects wrinkling, rupture and weld-line movement, using finite element method(FEM) of DYNAFORM to study the influence of various factors such as BHF, concave die and punch round radius, thickness ratio, and friction coefficient in the deep drawing of TWBs, and using the method of FEM of ABAQUS to study the critical pressure stress changes, the drawing force and rupture force and wrinkling critical pressure and force changing with the deep drawing height. And the simulation results and theoretical results are compared, and the comparison results are analyzed to verify the correctness of the theoretical analysis model.In the process of experimental analysis of a cylindrical parts of TWBs, in order to ensure the forming effect of the welded plate cylindrical part, the structure device such as punch, concave die and blank holder is designed. Through the deep drawing experiments, the influence of plate thickness ratio, die radius and punch radius in the forming limit height of welded blanks is studied. Compare the experimental results and simulation results, the correctness of the conclusion is verified. These will lay a foundation for further research.