非对称管件内高压成形过程研究

Research on hydroforming of non-symmetrical tubular components

为了改善两端不对称形状管件内高压成形后的壁厚均匀性，提高管件内高压成形极限，采用Dynaform有限元模拟软件并结合实验，研究了补料压力、轴向补料量对管件成形过程中起皱和破裂的影响．结果表明：当补料压力低于32MPa时，失效形式为死皱；当补料压力高于42MPa时，失效形式为破裂，适宜的补料压力区间为34～42MPa；当左右补料量分别为42和22mm，整形压力126MPa时，可得到合格非对称瓶形管件，管件最大膨胀量为70．75％，壁厚最大减薄率为27．12％。通过控制管材在内压和轴向力的作用下发生合理的预成形，包括管材两端的合理补料量以及合理的起皱形状和数量，可在最终的内高压成形中实现更好的壁厚均匀性，提高成形极限。

In order to improve the wall thickness distribution and tube-forming limits of hydroformed asymmetri- cal tubular components, the internal pressure during feeding and axial feeding which affect the wrinkling and bursting of hydroforming were studied in this work. The hydroforming process was simulated by using Dynaform software and the experiments were done at the same time. Wrinkling occurred when the pressure was below 32 MPa during feeding and bursting occurred when the pressure was above 42 MPa. It was suitable for prc- forming between 34 - 42 MPa. With left axial feeding of 42 mm and right axial feeding of 22 mm, an asym- metrical tubular component was formed successfully at the maximum pressure of 126 MPa. The maximum ex- panding and thinning of this component were 70.75% and 27.12% respectively. It is shown that a uniform wall thickness distribution and high forming limits could be obtained through the proper pre-forming. The shape and quantity of wrinkles and the match of internal pressure and feeding was optimized to attain a uniform wall thickness distribution and a higher forming limits.