Experimental study and regression analysis of free and die forming of circular metallic plates using gas mixture explosion

In this paper, experimental and regression analysis of the effective parameters in the free and die forming of circular metallic plates using gas mixture detonation were investigated. In the experimental section, steel, aluminum, and brass plates in different thicknesses were used. To better evaluate the experimental results, the condition of the same areal density was used to compare the results of steel, aluminum, and brass plates under the same loading conditions. In the regression analysis section, the Design-Expert software package and response surface methodology were used. The effect of parameters measured in experimental tests including the pressure of Oxygen, the pressure of Acetylene, plate thickness and die apex angle on the deflection of circular plates were investigated simultaneously. To find a significant model, the confidence level of 95% was considered in the analysis. Experimental results showed that using a die with an apex angle of 60° leads to the decrease of the maximum permanent deflection. On the other hand, using aluminum and brass plates in the die forming resulted in a more reduction of permanent deflection in comparison with free forming. The results of the regression analysis show that the predicted values of the model are in good agreement with the experimental data and the presented model is suitable. Optimal conditions for the minimum deflection of the circular plates under explosive loading were also presented. The pressure of Oxygen and the die apex angle has the highest effect and the least effect on the forming of circular metallic plates.