An Application of the Bees Algorithm to Pulsating Hydroforming

Abstract

Pulsating hydroforming is a sheet forming process proposed in the last decade. The numerical simulation of this process requires biaxial stress–strain curves which can be obtained by performing a pulsating hydraulic bulge test. In this study, the input parameters of a pulsating hydraulic bulge test with titanium alloy sheets (Ti-6Al-4 V) are optimised using the Bees Algorithm (BA). The input parameters are amplitude and base pressure; bulge height (h) and minimum thickness (t) at dome apex are outputs. The mathematical modelling of h and the design of an objective function (J) are needed for optimisation. A second-degree polynomial equation is derived for h using curve fitting for three frequencies. Additionally, t is calculated depending on h. The objective function is designed for maximum normalised bulge height and minimum normalised thickness. The results show less thinning at the dome apex with a bulge height similar to that of the traditional monotonous method. Thus, a uniform thickness distribution, which is a critical quality indicator in hydroforming, is obtained with acceptable loss in bulge height. After optimisation, ?t (t-t0) is improved by approximately 9%. The bulge height increases by 15 and 13% in the best experimental case and the BA-optimised results, respectively. Consequently, the ductility of Ti-6Al-4 V sheet is increased, and the input parameters are optimised. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.