Sheet Forming And Numerical Simulating Analysis On Dies

With introducing in more-advanced techniques and innovating self-owned techniques, the level of automatic production in the field of stamping dies has been improved a lot already in our country, and by now the technological collection of CAD/CAM/CAE has become more and more important than anytime before. However, CAE simulating techniques were researched too late to reach a wide range of usage in the market by now with related undeveloped techniques.Sheet forming CAE technique has been developed from the base of FEM and computer techniques. In this thesis, the development, characteristic and the usage range of the both-here-and-broad FEM (Finite Element) simulating technology are introduced systemically in the round, especially the practical characteristic of dynamic explicit FEM simulating technique DYNAFORM.Those large auto panels of large size, complicated deform and unequal stress when stamping do bring forward a good much hardness for manufacturing and forming forecasting. In this thesis, aiming at the typical stamping part supplied by a company, applying dynamic explicit FEM simulating technique DYNAFORM, concrete solutions to wrinkle and break which occur frequently in stamping process have been introduced, and the way to optimize the blank has been given out also, which made a great help to manufacturing.Spring-back is an essential thing in auto stamping parts, however, it should be controlled exactly for requirements of assemble and weld. Aiming at a typical large-bending auto longeron, this thesis systemically analyzed the reason for how spring-back produced and the ways how to control it. Based on CAD software UG NX4.0, different ways to control the spring-back have been brought forward. At the end it showed out that the variable blank holder force had a wider range of usage than the even blank holder force, and also could control the spring-back and blank forming.By analyzing the forming characters of large bending parts, key factors influencing directly the forming degree of redundancy and the spring-back have been obtained, which are blank holder force and the gap between punch and die. Combining the orthogonal trial design and the variable blank holder force process, the influencing tendency to the forming degree of redundancy and the spring-back from gap and other parameters has been analyzed. And at last, an optimized design solution has been promoted under the variable blank holder force process, and by using optimized parameters a small spring back could be obtained. It satisfied the requirement of manufacturers and auto assembling.