Prediction Of Wall Wrinkling In Deep Drawing Of Conical Parts

It is generally known that conical cup part is one of the most typical curved parts. Side wall wrinkling occurs far more easily than flange wrinkling since the wall is relatively unsupported by the tools in the process of deep drawing. Side wall wrinkling is one of the major failure modes. This failure can adversely affect the part functions; severe wrinkling may damage or even destroy dies. Therefore, Prediction and prevention of wrinkling has an important significance in sheet metal forming. It is necessary to study forming mechanism of side wall wrinkling and to explore material parameters and process parameters influence rules of on side wall wrinkling.First, According to the characteristic of conical part in deep drawing, the blank was divided into five areas: the bottom of cone, punch fillet area, side wall, die fillet area and flange. It was discussed the stress and strain distribution of wall part and the flange at the same time. Subsequently, the main stress method was used to deduce stress distribution of flange and side wall area. It turned out that side wall wrinkling may occur in the side wall near the die fillet radius.Then, The finite element simulation software ABAQUS/Explicit was applied to analysis deep drawing of the conical part, moreover, this paper expounds the processing method of critical technology, such as selection of element type, material model, grid partition, selection of contact and friction, applied load and the processing of boundary condition. The simulated results agree with theoretical analysis, it proves the rationality of the simulation.Next, Energy method and incremental theory was applied to establish the theory of conical side wall wrinkling. It was acquired that critical compressive hoop stress expressions of side wall wrinkling, required date was extract from ABAQUS finite element simulation, and written into a program by MATLAB. This method implement for prediction of side wall wrinkling.Finally, It was analyzed numerous factors influence regular of predicted side wall onset of wrinkling. These factors include deflection function, yield criterion, material parameters and process parameters. Elastic modulus, Poisson’s ratio, coefficient of strain hardening, coefficient strength, normal anisotropic coefficient and the thickness of the sheet metal are the mainly material parameters. Process parameters cover blank-holder force, die fillet radius of die, clearance, friction factor. This article provides a wonderful reference value on prediction and prevention of wall side wrinkling in deep drawing process.