多层U形波纹管的疲劳寿命有限元分析

Finite Element Analysis to Multilayer U-shaped Bellows' Fatigue Life

应用非线性有限元法,综合考虑几何非线性、材料非线性和边界非线性等因素,采用平面轴对称单元和柔性的面-面接触对,建立了多层U形波纹管的非线性有限元模型,较好地解决了层间的接触问题。借助ANSYS软件对多层波纹管在轴向载荷与内压组合作用下的应力分布规律进行了探讨,利用结构的局部应力应变状态对波纹管的疲劳寿命进行了预测,同时考虑了波纹管的层数、壁厚减薄效应以及内压大小对于计算结果的影响,为波纹管的疲劳设计提供了依据。

Nonlinear finite element models of multilayer U - shaped bellows are established via axisymmetric plane element and flexible surface - to - surface contact pair on the base of nonlinear theory, including boundary nonlinearity, material nonlinearity and geometrical nonlinearity, in which interfaces between layers are well considered. Stress distribution under the interior pressure and axial displacement was studied, and the fatigue life of bellows is predicted based on local stress - strain results. The paper focuses on the effects of different conditions, such as the number of layers, wall - thickness variation and interior pressure, which provides evidence for the fatigue design of bellows.