Research On Finite Element Analysis Of Concave Blank-Hold Surface In Stamping Process

The structural characteristics of autobody panel, which is always made up of three-dimensional surfaces, determine the complexity of its formation law in stamping processes. Many autobody panels have curved flanges or ports, and their formation laws are very complicated. Besides, subjoining the curved ports to planar ones will not only increase the complexity of forming capability but also be a waste of materials. Accordingly, study of the stamping laws on curved blank-hold surfaces is very pivotal in the autobody panel's forming processes.In this paper, a new classification method of blank-hold surfaces is proposed in terms of the existent forms of flange blank-hold surfaces of practical use. And the software eta/DYNAFORM, a commercial FEM (Finite Element Method) software, which is specially used to analyze sheet metal forming processes, is applied to simulate the forming disciplinarian of rectangular part with concave blank-hold surfaces. Through this way, the effects of the dimension parameters of concave blank-hold surfaces are proposed, including fracture disciplinarian, wrinkling disciplinarian and the disciplinarian of correlative parameters for those lapses.In addition, in this paper, some conclusions can be drawn. Firstly, it can be concluded that the basic affecting parameters of concave blank-hold surfaces are the length of the straight side of the curved blank-hold surface L, the radius of cylinder surface R and the radius of the transition of different blank-hold surfaces r, and their effects to the drawing process is well-regulated. Secondly, the conversion of fracture modes of square box parts is controlled by the radius of blank-hold surfaces'transition r. And also the critical radii rc of different combination parameters of R&L were proposed. According to this research, it can also be concluded that the effect of r is independent and the critical radius rc can be used in sequent research processes as reference. Thirdly, the thinning distribution of the side wall of square box part and the wrinkling modes are controlled by the combination of R&L, which are the main parameters of the curved blank-hold surfaces. On the one hand, we can conclude that the degree of asymmetry of the side wall in the field of curved blank-hold surface is apt to - II -...