The Deep Drawing Process Of Square Box-shaped Pieces Pull Bhf Calculation And Control Model

On the base of deeply researching forming mechanism of rectangular part,the paper gave the mode of ploting flange of squarebox part when balnk holder is changing;By mechanical analysis, thinking about strain laxity gene^ plyanisotropy factor, strain hardening exponent thickness, friction, the paper gave law of distribution of stress and strain in deformation squarebox; According to diffuse instability criterion, worked out the principle of verdicting the case of base fracture or side fracture and formulae of fracture limit BHF; combining produce practice ,put forward flexibility function:in term of energy theory,thinking about deformation uniformity, educed the formulae wrinkling limit BHF in the case of circle wrinkling and straight side winkling; designed calculate examples, particularly illuminated appling formula of fracture limit BHF and formulae wrinkling limit BHF to determine the best contral mode of BHF, analyzed relation between plyanisotropy exponent r, strain hardening exponent n and friction coefficient μ with BHF; contrasting with literature, analyzed the cause of difference between the mode in the paper and conclusion have been educed and indicated the conclusion of this paper is more reasonable.