Optimization of Effective Parameters in Free Iron Sheet Forming Process by Underwater Explosion Method

One of the objectives of the present study is to optimize the effective parameters in the free sheet forming process under underwater explosive loading. In the experimental part, in order to investigate the effect of loading type on the maximum permanent deflection and thickness distribution of the plate, blasted-loaded plates due to 12 g and 4 g of explosive charge were used for single loading and repeated loading, respectively. Also, in order to investigate the effect of effective parameters on the process and optimize them, the Coupled Eulerian-Lagrangian method was firstly used for numerical simulation in ABAQUS finite element software. Then, in the optimization section, in order to investigate the simultaneous effect of explosive charge mass at each stage and the standoff distance on the maximum deformation and thickness of the sheet, Design-Expert software and Response Surface Methodology were used. The p-value obtained for the proposed model was less than 0.05, which indicates the significance of the model with a reliability of over 95%. The obtained results showed that the model provided by the software is suitable for this experiment and the values obtained from predicting the model are consistent with the experimental and numerical results. Also, the optimal conditions for the least change in plate thickness and the highest amount of permanent deflection were presented.