A Kriging-based non-probability interval optimization of loading path in T-shape tube hydroforming

In this study, the interval optimization method, in which the bounds of uncertain parameters are only required and knowing their probability distributions are not needed, is introduced to deal with limited information in T-shape tube hydroforming. The contact area between the counter punch and the tube is taken as the objective function and the protrusion height and maximum thinning ratio as constraints. To control the possibility degree of failure associated to each constraint, the reliability-based possibility degree of interval method is adopted to evaluate the reliability of T-shape tube hydroforming process. Before optimizing the process, the finite element model is validated against experimental results, and Taguchi method is employed to screen key factors from a number of potential factors. In addition, to improve computation efficiency, the Kriging model is adopted to construct the surrogate model, and the performance of the resulting surrogate model is validated using cross-validated method. Finally, the Kriging based on interval optimization method is applied for loading path design in T-shape tube hydroforming, and the results show that the robustness and reliability of the process can be guaranteed.