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Prediction and prevention of wrinkling are very important in tool design and determining the effective parameters in sheet metal forming processes. In forming metallic cups, wrinkling generally occurs in the two regions of flange and wall. The control of wrinkling in flange area is not so difficult by controlling the blankholder pressure, but it is difficult in the wall region because the sheet is not supported in this area. In this paper, using a geometric method based on numerical simulation, the wrinkling in the wall of the symmetric conical parts in the developed hydrodynamic deep drawing with radial pressure and inward flowing liquid is investigated. In the process, two independent pressure supplies have been used for forming the sheets. Due to the nature of the process, the effects of radial and cavity pressures on wrinkling have been investigated. In addition, the effects of material, initial blank thickness and punch velocity on wrinkling in wall area were investigated. To verify the results of the simulation, several experimental tests have been done on the St13 and copper sheets. Good agreement between the simulation and experimental results shows the reliability of this method in the wrinkling study. It was also demonstrated that increasing the maximum radial pressure or decreasing cavity pressure leads to increasing wrinkling. Additionally, wrinkling was decreased with increasing blank thickness. Moreover, it was shown that wrinkling simulation is much depended on input parameters such as punch velocity and appropriate element size

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Hydroforming is a convenient method for applying fluid to produce parts with high strength to weight ratio. Hydrodynamic deep drawing assisted by radial pressure with inward flowing liquid process is considered as a type of hydroforming. In this method, radial and cavity pressures are two most important parameters, the values of which at any moment play an important role on the quality of final part. In this study, based on a hybrid method, the cavity and radial pressure paths in hydrodynamic deep drawing assisted by radial pressure with inward flowing liquid process are optimized. In this method, an adaptive simulation that is integrated with the fuzzy control system with the ABC algorithm is used to determine the optimized radial and cavity pressure paths. The achievement of a cup with least thinning and without wrinkling has been defined as the optimization goal. The validity of radial and cavity pressure paths obtained from optimization algorithm is verified through an experiment. Results showed that utilization of the optimized loading path yields the part with lower maximum thinning and without wrinkling.