高钢级管道环焊缝的应变集中特性研究

当管道穿越地质灾害多发地区时,可能会受到较大的位移作用。管道环焊缝处的结构特性及材料特性使其在位移作用下,将会产生局部的应变集中并发生开裂,从而影响管道的应变能力。因此,研究管道环焊缝处的局部应变特性,对于管道的安全评价具有重要意义。研究采用有限元模拟,结合材料损伤模型的方法进行,分析了低匹配及热影响区软化的高匹配环焊缝的应变分布。结果表明:对于低匹配环焊缝,应变集中的位置处于热影响区与焊缝交界的外表面。对于热影响区软化的高匹配环焊缝,应变集中位置会随位移及内压的变化而变化。内压对环焊缝应变集中程度具有重要影响,并可以显著降低管道的应变能力。

Strain Concentration Characteristics of Girth Welds in High-grade Pipelines

When the pipeline passes through the areas where geological disasters occur frequently,it may be subjected to a displacement.Under a lager displacement,the structure and material characteristics may cause local strain concentration and cracking in girth welds,thereby affecting the strain capacity of pipelines.Therefore,investigating the local strain characteristics of girth welds is of great significance for the safety assessment of pipelines.The research is carried out using finite element simulation combined with the material damage model.The strain distributions of undermatching girth welds and overmatching girth welds with softened heat affected zone are analyzed.The results show that for the undermatching girth welds,the strain concentration occurs on the outer surface of the interface between the heat affected zone and the weld.For the overmatching girth welds,the location of the strain concentration will change with the changes of displacement and internal pressure.The internal pressure has a significant effect on the degree of the strain concentration of the girth welds,and can significantly reduce the strain capacity of pipelines.The research results can provide reference for the design and evaluation of girth welds in high-grade pipelines.