弯头爆裂原因分析

Analysis on Causes of Elbow Burst

某输气管道埋地弯头在水压试压时发生爆裂,调查了弯头发生爆裂的情况,通过断口分析、性能测试、有限元估算及水击分析对弯头失效原因进行了分析及验证。结果表明:由于结构的原因,弯头内侧的应力和应变最大,在结构应力、残余应力、水压压力及水头压力所形成的组合应力作用下,弯头首先从内侧发生屈服,最终爆裂,弯头失效的主要原因为弥合水击所致。

The bursting cause has been investigated on one buried elbow of a gas pipeline which burst during the hydraulic pressure test. The cause has been analyzed and evaluated by means of the fracture analysis,performance testing,finite element estimation and close surge analysis. The results showed that the elbow’s structure caused the stress and strain of the inside elbow at the maximum values together with the effect of the structure stress,residual stress,hydrostatic pressure,and the head pressure of combination stress. Then the elbow started to yield from the inside of the elbow,and eventually caused the failure. The main reason of the elbow bursting was the close surge.