U型膨胀节热应力分析及疲劳寿命估算

THERMAL STRESS ANALYSIS AND ESTIMATED FATIGUE LIFE OF U-TYPE EXPANSION JOINT

本文用有限元方法对在工程中经常使用的单节膨胀节和我们新设计的双节膨胀节在温度荷载及内压联合作用下的变形和内力进行了计算分析和疲劳寿命的估算。分析结果表明,在相同荷载条件下,双节膨胀节的有效应力比单节膨胀节的有效应力最多可降低41.6％,大大改善了膨胀节内部的应力状况;同时双节膨胀节的疲劳寿命比单节膨胀节提高69.6倍.本文的分析结果为膨胀节的改型设计提供了理论基础。据此设计的双节膨胀节已在工程实际中得到应用。

The thermal stress and deformations of two kinds of expansion joint one-section and newly designed two-section under tempcrature load and internal pressure were analysied by Finite Element Method. Estimated fatigue life of the two kinds of expansion joint were given by engineering standard. The results show that compared with the one-section joint, the effectivc stress of two-section expansion joint can be reduced by 46.6％, and the fatigue life of two-section expansion joint is 69.9 times as much as that of one-section. The results have provided a theoretical reference to the future design of expansion joints, and the newly designed two-section expansion joint has been used in engineering practice.