Critical blank-holder force in axisymmetric deep drawing

An analytical approach for predicting the critical blank holding force (BHF) was presented. Using energy method, the analysis provides the circumferential stress and the equivalent strain as functions of radius under the plane strain and the equivalent strain is inversely proportional to the radius respectively. The maximum relative errors of the circumferential stress and the equivalent strain are 22.3% and 35.9% respectively under the two conditions for some dimensions of sheet and die. In addition, the relationship between BHF and wrinkle number was obtained under the assumption that wrinkle shape is expressed by power function. The critical BHF under plane strain was analyzed for the wrinkle shapes when the power is less than, equal to or greater than 1. The effects of wrinkle shapes on the critical BHF are also presented.