工况对管道凹陷形成及管道安全性的影响

基于X70管道和刚性压头模拟管道外壁与硬物挤压或碰撞形成凹陷的过程,建立对象接触、外载荷加载、外载荷卸载有限元分析模型,将内压、外载荷的加载、卸载按照特定顺序组合构成影响管道凹陷状态的3种工况,研究3种工况下凹陷对管道应力、凹陷回弹及极限承载力能力的影响规律。研究结果表明,工况1、工况2下的最大等效应力发生在凹陷加载阶段,工况3下的最大等效应力发生在内压加载阶段。工况1下的凹陷回弹系数为0.403,工况2和工况3下的分别为0.45和0.759。工况2下管道极限承载力受凹陷深度影响最严重,工况3下管道极限承载能力受凹陷深度影响最小。

Influence of Working Conditions on Pipeline Depression Formation and Pipeline Safety Property

Based on the X70 pipe and rigid pressure head to simulate the process of squeezing or colliding the outer wall of the pipe with a hard object to form a depression,a finite element analysis model for object contact,external load loading,and external load unloading was established,and the loading and unloading of internal pressure and external load were specified.The sequence combination constitutes three working conditions that affect the sag state of the pipeline,the influence law of the sag on the pipeline stress,concave springback and ultimate bearing capacity under the three working conditions were studied.The research results show that the maximum equivalent stress of condition 1 and condition 2 occurs in the sag loading stage,and the maximum equivalent stress of condition 3 occurs in the internal pressure loading stage.The recessed springback coefficient of working condition 1 is 0.403,and that of working condition 2 and working condition 3 are 0.45 and 0.759 respectively.The ultimate bearing capacity of the pipeline in condition 2 is most affected by the depth of the depression,and the ultimate bearing capacity of the pipeline in condition 3 is least affected by the depth of the depression.