Optimal design of superplastic forming processes

A systematic method to find the optimal blank shape for sheet forming is proposed by combining numerical simulation and optimization technique. A weighting parameter is introduced in order to simplify the multi-variable optimization problem to a single-variable problem. The proposed method has been applied to the blank design of superplastic forming to obtain uniform thickness distribution after forming. The result shows that uniform thickness distribution can be obtained within the required error bound with the optimized blank. A relevant experiment was performed which showed good agreement with the prediction, thus validating the method. In addition, the optimized blank is found to yield more uniform strain distributions, implying an improvement in formability.