Abstract
In deep drawing, tearing and wrinkling are major defects In order to avoid these defects, variable blank holder force (VBHF) trajectory should be optimized for successful sheet forming Numerical simulation is so expensive that sequential approximate optimization (SAO) is valid for optimization In particular, the relationship between tearing and wrinkling is conflicting, and multi-objective design optimization is considered in this paper To find VBHF trajectory under conflicting relation, sequential approximate multi-objective optimization (SAMOO) is applied The forming limit diagram (FLD) is used to evaluate tearing and wrinkling Also, the total stroke is divided, and the blank holder force of each sub-stroke step variable is taken as the design variables Numerical result shows that the VBHF trajectory can successfully form the product without tearing and wrinkling
