Optimization of the load path for tube hydroforming processes using fuzzy logic

Today, Production in the shortest possible time, with the lowest cost and highest quality is the one of the most important criterions in the industry. Tube hydroforming (THF), because of its unique feature, increasingly used in military, industries, automobile manufacturing, aerospace, and bicycle industries. Most tube hydroformed parts are produced by a multistage loading process which the suitable loading condition in THF with regard to internal pressure and axial feeding should be designed to improve formability and to avoid failure modes on the final hydroformed product. This study deals with the procedure for the determination of the proper loading path in THF using a fuzzy logic control algorithm, which avoids the failure of the tube due to excessive induced strain during the forming process. For this purpose, Mamdani fuzzy control algorithm was used in conjunction with Abaqus FEA code for simulation of the THF process. The wrinkling measurements and the thickness variation obtained from simulation are used as input in fuzzy control and fuzzy control outputs are used to set the loading path. A controlled algorithm is designed to maximize the expansion of the tube and minimize the thickness variation of the wall and wrinkling at the same time. The numerical results were verified and validated by conducting experiments where a good agreement was obtained between the experimental results and simulations