The use of MCDM techniques to assess fluid pressure on the bending quality of AA6063 heat-treated tubes

This paper investigates the bending of aluminum tubes under different fluid pressure and heat treatment conditions. The application of multi-criteria decision-making (MCDM) methods was evaluated for selecting the best forming condition considering cross-section ovality, thinning, and thickening of the bent tubes. Analytic hierarchy process (AHP) was used for criteria weighting, and technique for order of preference by similarity to ideal solution (TOPSIS) and multi-objective optimization on the basis of ratio analysis (MOORA) were used for alternative ranking. A combination of various types of AA6063 tubes, including as-received (R), annealed (O), and artificial aged (T6), with different fluid pressures (0, 1, 1.8, 3.2, and 3.6 MPa) were assumed to be as the alternatives (forming conditions). The results demonstrate that the ovality and thickening of the bent tubes decrease by increasing the internal fluid pressure. On the other hand, increasing the internal fluid pressure gives rise to an increase in thinning of bent tubes. The O sample has the lowest ovality and thickening while the T6 sample has the lowest thinning. MCDM analysis revealed that the O samples at higher pressures show better bendability.