Hydroforming simulation and analysis of Ω-shape expansion joint

Abstract

In this paper, the finite element simulation software ANSYS Workbench Transient Structural module was employed to simulate the hydroforming process of a three-layer threewave Ω-shape bellows. The stress and strain fields, the wall thickness thinning rate at the peak and the roundness of each layer after hydroforming of the Ω-shaped bellows were analyzed. Results show that the maximum equivalent stress of vonmises before unloading is mainly distributed on the large arc. But after unloading, the maximum equivalent stress of vonmises is mainly distributed at the transition between the large arc and small arc with the maximum stress being about 33.15% lower than that before unloading. The maximum value of the equivalent total strain of vonmises before and after unloading is always near the maximum displacement of the bellows along the direct ion of wave height with the maximum being about 0.2.The elastic springback in the direction of wave height after hydroforming is about 1.70mm. The wall thickness thinning rate at the peak of the three-layer three-wave Ω-shape bellows is as large as 14 %.