基于蠕变的高温法兰连接系统寿命预测方法

Life expectation method of flanged connections based on creep analysis at elevated temperature

长期工作在高温下的法兰连接系统 ,由于密封垫片和螺栓的蠕变松弛 ,使得垫片上的残余压紧应力逐渐减小 ,并最终导致连接系统的泄漏失效。在考虑垫片和螺栓蠕变的基础上 ,对连接系统进行变形协调分析 ,建立了高温下法兰连接系统的变形协调方程 ;进而导出了垫片残余应力与时间的关系式 ,即变形协调率型方程 ;根据紧密性概念 ,以最大允许泄漏率为失效准则 。

Creep relaxation of bolted flanged connections often gradually results in residual stress reduction of the gasket, and lead to leakage failure of bolted flanged joints at elevated temperature. In this paper, the load deformation equation of joints with time parameter was derived considering the creep of gasket and bolt. According to the definition of tightness, a life expectation method of bolted flanged connections was put forward at high temperature, which was based upon the failure rule of maximum allowable leakage rate.