Numerical Simulation Optimization & Experimental Validation Of Laminose Tubular Stepped Part Forming Process

Punch forming of sheet is used widely in the industries of Auto, electric appliance and aviation, etc. The numerical simulation technology of sheet forming has been developed rapidly since 1970s. Especially with the rapid development of computer, the numerical simulation technology of sheet forming has tended towards the practical stage and changed the traditional design of sheet punch forming.According to the technological characteristic of the forming of stepped tubular part, the one-off drawing of stepped tubular part is divided into two stages in the paper. The one is the initial stage where the endured force of blank is similar to the drawing of conical part. In the process of forming, the formed blank is divided into five regions: flange, die horn region, hanged free surface between die and punch, punch horn region and the bottom of taper. The other one is the final stage in which the endured force of blank is similar to the bulging. The formed zone is divided into five regions of flange, die horn region, bulging region in the surface of ladder, punch horn region and the bottom of cylinder. In the paper, theoretical analysis method is applied to analyze the endured force of these important regions, determine the style of forming in these regions and reveal the technological characteristic of the forming of stepped tubular part. It is the first time to divide the one-off drawing of stepped tubular part into two stages from the forming mechanics theory. By these methods, it established the basis in determining the forming law of one-off drawing.In the paper, the finite element simulation software DYNAFROM is applied to analyze the affect of different blank holder during the forming process of laminose stepped tubular part, predict the possible defects such as wrinkle and break, obtain the rational style of blank holder avoiding the occur of defects and determine the rational configuration of die. The forming affect of thin-wall shallow stepped tubular part is analyzed when using different lubricate condition (friction coefficient). By this method, the relationship between friction coefficient and drawing depth of laminose stepped tubular part is obtained. The distribution of stress and strain and the variety of blank thickness is analyzed during different forming stages of laminose stepped tubular part. The condition of one-off drawing of laminose stepped tubular part is obtained.Plasticity theory and numerical simulation technology of finite element are applied synthetically to analyze the forming technological characteristic of stepped tubular part,obtain the rational technological method and the forming law of one-off drawing of stepped tubular part. Validated the technological method and the law by the experimental result, it showed the veracity and reliability of the technological method and the forming law of one-off drawing of stepped tubular part which can be used directly to guide the production.