X80管道焊缝凹陷应力应变特征数值计算分析

Numerical calculation analysis of stress and strain characteristics of weld dent on X80 pipeline

针对含焊缝凹陷管道的失效和损伤问题,以X80管线钢为研究对象,基于热弹塑性理论对焊缝的熔覆过程进行了有限元模拟。将焊接残余应力以初应力方式与管道凹陷结合,研究了管道焊缝凹陷的应力-应变分布特征,并探讨了凹陷深度和内压对焊缝凹陷的影响。结果表明,焊缝凹陷应力-应变分布受约束、凹陷深度和焊缝余高的影响;焊接残余应力沿着焊缝至管道两端的方向逐渐减小,焊缝凹陷会导致焊接残余应力重分布,离凹陷越近,残余应力重分布越彻底;凹陷深度的变化不改变焊缝凹陷的应力-应变分布模式,只会影响焊缝凹陷的影响范围;内压会增大焊缝凹陷区域的应力,但不影响含焊缝凹陷管道的应力分布模式。

Aiming at the failure and damage problems of pipeline with weld dent,taking X80 pipeline as the research object,the finite element simulation was carried out on weld cladding process based on thermo-elastic-plastic theory.Combining the welding residual stress with the pipeline dent in the form of initial stress,and the stress-strain distribution characteristics of the pipeline weld dent were studied,and the influence of dent depth and internal pressure on the weld dent was discussed.The results show that the stress-strain distribution of the weld dent is affected by the constraint,dent depth and weld residual height.The welding residual stress gradually decreases along the direction from the weld to the ends of the pipe,and the weld dent leads to redistribution of welding residual stress.The closer to the dent,the more thorough the redistribution of residual stress.The change of dent depth does not change the stress-strain distribution mode of weld dent,but only affects the influence range of weld dent on the pipeline surface.The stress on the weld dent increases due to the increase of internal pressure,but it does not affect the stress distribution mode of the pipeline with weld dent.