Investigation Of The Square Cup Deep Drawing By Finite Element Method

The deep drawing process is a main practice for sheet metal forming. Parts manufactured by this way have been widely used in aerospace, automobile an electronics owing to their light weight, great interchangeability and low cost. Traditional design for deep drawing process often depends on the engineers'experience, so repeated debugging for different parameters seems to be inevitable. With the development of computer and simulation, finite element method (FEM) has been applied in deep drawing problems. But as three nonlinear problems are included, simulation of this process is still difficult. So there are both theoretic and practical values to seek for an optimization method base on FEM to find optimum processing parameters.Through deeply research and discuss on the nonlinear finite element theory, anisotropic yield criterion of Hill'48 is introduced and constitutive relation based on it is proposed. In the same time, the dynamic nonlinear explicit algorithm, BWC element and penalty function method are chosen for numerical simulation of deep drawing process. Based on the theory above, a numerical simulation model concerned with square cup deep drawing in NUMISHEET'93 is established in ABAQUS with elastic-plastic finite element method. By way of strain distribution and final shape, the simulated result is compared with that of the experiment. Through comparison, the model turns out to be correct.After that, influences of major parameters in deep drawing process which consist of punch velocity, blank holder force, friction coefficient, radius of die corner and gap of model are investigated through different angles such as failure of crack and wrinkle, thickness and strain distribution, forming force, forming limit diagram, etc. Regions on which each parameter mainly influences and regularity of them are discussed in detail.Furthermore, criterion functions used to evaluate tendency of crack and wrinkle are established, and a criterion function based on them is built to evaluate the global formability of drawing parts. By means of uniform design method and numerical simulation, optimum processing parameters are found for square cup deep drawing, which proves that this optimization method for deep drawing process parameters is feasible and effective.