管状构件充液压形回弹规律研究

The mechanical mechanism of the springback of low-pressure tube hydroforming (LPTH) section was revealed based on elastoplastic machanics theory. The effects of main process/ geometric parameters, such as internal pressure, corner radius and wall thickness, on the springback were studied combind with finite element simulation and experiment. The results indicate that different from expansion deformation, the LPTH mainly relies on the bending moment to force the pipe material to undergo plastic deformation and thereby obtain the desired shape. Consequently, springback appears after unloading. However, it is found that the springback of LPTH can be effectively controlled by adjusting the internal pressure. There is a critical pressure which can induce pure bending deformation and result in the largest springback. Consequently, the LPTH should be avoided under this critical pressure. Whatever the internal pressure is greater than or less than the critical pressure, springback can be suppressed, and the former has a more obvious effect. In addition, bigger corner radius can also contribute to decrease the springback because of the larger tensile force under the same internal pressure. For a definite tube component, improving internal pressure is the effective method to decrease the springback.