局部应力-应变法预测大型波纹管的疲劳寿命

STUDY OF FATIGUE LIFE PREDICTION FOR LARGE BELLOWS EXPANSION JOINTS BY LOCAL STRESS STRAIN METHOD

鉴于大型波纹管膨胀节全尺寸疲劳寿命试验在工程上实现的困难性，研究了基于局部应力－应变法预测大型波纹管的疲劳寿命。应用非线性有限元获取波纹管的最大局部应力应变，并据此局部应变设计简化的试板。当弯曲试板上的最大应变等于波纹管的最大局部应变时，板的弯曲疲劳试验寿命即可代替波纹管的试验寿命。本方法在工程设计中被证明是实用且可靠的，它也适用于低压工况下通用尺寸波纹管的疲劳寿命的预测。

Based on the local stress strain method, the fatigue life of large bellows expansion joints is predicted. By the application of non linear finite element method, the maximum stress strain of bellows expansion joints is obtained. Then, a simple test plate is designed by the stress strain distribution on the bellows expansion joints. The fatigue test of the bellows expansion joints is replaced by the bent fatigue test of plates when the maximum strain of bent test plates equals to the local strain of bellows expansion joints. The method proposed in this paper is proved not only practical but also reliable in engineering design. It can also be applied to life prediction for normal size of bellows expansion joints under low pressure working condition.