Uniform thickness distribution oriented preforming design of tube hydroforming with rectangular section

To achieve the required rectangular section with uniform thickness distribution by hydroforming, three preforming methods by rigid mould are designed to fit the final process. Numerical simulation by the software LS-DYNA has been utilized to imitate the real experiments. With two-step computing, the numerical simulation brought the simulation results of preforming into the following hydroforming process to get the reliable rectangular filling results and thickness distribution regularities. The data resulted from simulation of each design has been figured out and compared to the consequence of a normal preforming design. A realizable preforming design for tube hydroforming with rectangular sections is presented and recommended, which kept the maximum of the thickness reduction lower than 10% and the thickness of the special area from the straight side to the corner point well-distributed. The experiment verified the simulation results.