Development And Application Of Equivalent Drawbead Model Based On ABAQUS Software

In the industry of automotive, aviation and household appliances, the sheet metal forming parts is applied widely increasingly.The drawbead is an important part of the sheet metal forming die. When we do research on the drawbead using the method of finite element model,it is more difficult to solve the numerical problem as we use the real drawbead.Because it has small size and complex structure, and should be divided into small units. So we often use equivalent drawbead model instead of the real model in order to simplify the solving problem. As a consequence of the exiting equivalent drawbead model can not the deformation state and the change of material properties of the sheet after the drawing of real drawbead, a set of equivalent drawbead model considering the drawbead restraining force, the cumulated strain and the change of material mechanics performance is established.With ABAQUS software as a platform,through establishing drawbead rigid surface and increasing the local friction coefficient between its surface and the plate, the addition of drawbead restraining force effect is achieved. Based on the second development, the UMAT subroutine containning two material models,the URDFIL subroutine and the contact judgement program segment is written in FORTRAN language. They are used to change the material mechanics properties. The UMAT subroutine is proved to be correct trough applying it in the single plate unit single pull numerical simulation study and tensile model of sheet over rigid surface is applied to verify the material properties changing subroutine.The equivalent drawbead model is developed by integrating the above subroutines, then it is used to be compared with the real unit drawbead model, after which the equivalent drawbead model is modified. The equivalent drawbead model,which is finally established,is applied to the numerical simulation of box shaped parts in deep drawing forming. According to the comparison between numerical simulation and experiment, and the validity of the equivalent drawbead model is proved.