Optimal Experiment Selection in Hydroforming Process of Bimetallic Sheets Using CRITIC, MEREC and TOPSIS Techniques

The present research work is related to the optimal experiment selection of the bimetallic sheet hydroforming process using multi-attribute decision making (MADM) techniques. The numerical simulation of the operation has been done by applying the ABAQUS software. The studied geometrical variables include the punch tip radius (Rp), the die entrance radius (Rd) and the clearance between the punch and matrix (CL), and the target parameters are the maximum thickness reduction and thickness variation of the final product. In order to calculate the weight of the objective function in sheet hydroforming process, criteria importance through inter-criteria correlation (CRITIC) and method based on the removal effects of criteria (MEREC) techniques were employed. In the following research, a technique for order preference by similarity to ideal solution (TOPSIS) has been used to evaluate the numerical test and assess the best case. The results demonstrated that the weighting coefficients of the two objective functions, namely thickness reduction and thickness variation obtained from CRITIC and MEREC methods, was almost the same. Their values were calculated at approximately 0.6 and 0.4, respectively. Based on the optimization outcomes, the optimal values of Rd, Rp, and CL gained were 6 mm, 4 mm, and 2.2 mm, respectively.