Strategies for blank holder force and pressure design through fea simulation in sheet hydroforming

Abstract

To determine loading paths of blank holder force (BHF) and pressure in hydromechanical deep drawing (HMD) process of the parabolic cups is aim of this research. The process of HMD, the sheet is formed against a counter pressure in the pot rather than a female die in regular stamping operation. Successful HMD process requires the optimum relationship of the key process parameters. Excessive BHF leads to the part thinning. Conversely, insufficient BHF can lead to flange wrinkle. In case of pressure, excessive pressure leads to the part thinning. In opposition, insufficient pressure can lead to side wall wrinkle. Trial-and-error for the process design can be very time consuming. Finite element method coupled with optimization technique is applied to determine the proper constant BHF and proper linear counter pressure. The adaptive finite element method coupled with fuzzy logic control is applied to determine loading profiles of BHF and pressure just one simulation. The parabolic parts are used to investigate. The thinning is the index to compare the quality of part. The crack and wrinkles will be disappeared at the end of stroke.