管道裂纹有限元分析与ECA评估研究

Finite Element Analysis and Engineering Critical Assessment of Pipeline Crack

油气管道输送介质具有易燃、易爆特性,所面临的危害因素多,运营风险高,特别是管道出现裂纹的危害较大,在疲劳、应力腐蚀的作用下易导致管道破裂失效。本文针对某长输管道内检测中发现的裂纹,基于静裂纹的模拟方法在对含裂纹缺陷管道进行有限元模拟计算方面,具有更高的计算精度和效率,建立了静裂纹管道的有限元模型,采用运动式耦合方法与管道端面进行耦合,获得裂纹尖端张开位移(Crack Tip Opening Displacement,CTOD)随应变的变化关系,并使用FAD图(Failure Assessment Diagram)评估方法进行工程失效评估,最终有效评估管道的安全性,该方法的联合使用,对于含裂纹管道的安全性精准评估具有重要意义。

The transmission medium of oil and gas pipeline has the characteristics of inflammable and explosive, which is confronted with many harm factors and high operation risk. In particular, pipeline cracks are easy to lead to pipeline rupture and failure under the action of fatigue and stress corrosion,and cause serious damages. In this paper, aiming at the cracks found in the detection of a long-haul pipeline, the simulation method based on static cracks has higher calculation accuracy and efficiency in the finite element simulation calculation of cracked defective pipelines. The finite element model of the pipeline with static cracks is established, and the kinematic coupling method is adopted to coupling the pipeline end face.The crack tip opening displacement change relationship with strain was obtained, and the failure assessment diagram was used to evaluate engineering failure. Finally, the combined application of this method is of great significance for accurate safety evaluation of cracked pipelines.