含局部减薄弯头的非线性有限元分析

Nonlinear finite element analysis on the local thinned elbow

利用非线性有限元方法对含局部减薄缺陷弯头建立三维有限元模型,分析了在单一内压作用下弯头的弯曲半径、局部减薄缺陷的尺寸以及位置对塑性极限载荷影响,总结出含局部减薄缺陷弯头的塑性极限载荷的变化规律,得出相同弯曲半径和相同尺寸的局部减薄缺陷位于弯头内拱处时,弯头的塑性极限载荷值最小,位于弯头外拱处时其塑性极限载荷最大的重要结论,为含缺陷弯头的安全评定提供了一定的理论依据.

Local wall-thinning, which is a common defect on the surfaces of pipelines, can not only reduce the load-carrying capacities, but also cause the serious failure which occures accidents of pipelines. The paper establishes the 3-D finite element model for local thinned elbow, calculating the limit load of local thinned pressurized elbow . The limit load of the local thinned elbow is related with the defect position of local thinned area, curvature radius, and the axial size, circumferential size and the depth of the local thinning have a different influence on the plastic limit load. It is shown that the change law of the limit load of the local thinned elbow and the internal pressure failure mode of the local thinned elbow are gained.