Forming quality optimization of 2219 aluminum alloy thin-walled complex components based on fracture constraint in spin forming

The 2219 aluminum alloy thin-walled complex components manufactured by spin forming are frequently applied to the bottom end of rocket fuel tanks. However, fracture and quality problems (large part-mold contact gap, low roundness, thickness accuracy) are prone to occur during their multi-pass spin forming. While the material anisotropy, complicated components geometry and the complex stress state evolution make it difficult to obtain the appropriate forming process parameters in spin forming. With the help of finite element methods, it is possible to solve this difficulty. Thus, based on the anisotropic Barlat89 yield function and the DF2016 fracture criterion, a spin forming finite element model considering material anisotropy and damage evolution is established first for the components. Then, a method by using multi-pass involute spinning track with variable diameter base circle to form the components is proposed, and also the spinning passes are determined. Finally, taking the non-fracture as the constraint condition and the forming quality indexes (part-mold contact gap, roundness, and thickness accuracy) as the optimization objectives, a multi-objective optimization model based on orthogonal experimental design and response surface model is established. The optimized process parameters are solved and determined by a combination of the Archive-Based Micro Genetic Algorithm, and the optimized results are verified by the experiments.