摘要
裂纹是管道中常见的缺陷形式,其应力强度因子是开展管道安全性评价的重要依据。为了准确获得管道中裂纹的应力强度因子,采用1/4节点法建立了求解长输管道轴向穿透裂纹应力强度因子的有限元模型,并将有限元法和解析法求得的应力强度因子进行对比,验证了新建模型的可靠性。分析了内压、裂纹长度、内径以及厚径比对裂纹尖端应力强度因子的影响,同时探究了沿壁厚方向应力强度因子的变化规律。结果表明:内压、裂纹长度的增加,将会导致应力强度因子增大;内径、厚径比的增大,则会使应力强度因子减小,且当内径超过500 mm时,应力强度因子不再随着直径的增加而发生变化;管道外壁处应力强度因子始终高于内壁处,随着内压的增加,裂纹将从管道外壁启裂。采用1/4节点法计算裂纹尖端的应力强度因子,其操作方便、计算精度高,可为开展长输管道的安全评价工作提供参考。(图10,表6,参24)
Crack is a common defect form in pipelines,and its stress intensity factor is an important basis for safety evaluation of pipelines.In order to accurately acquire the stress intensity factors of cracks in pipelines,the finite element model for solving the stress intensity factors of axial through-wall cracks in long-distance pipelines was established by 1/4 node method.The reliability of the new model was verified by comparing the stress intensity factors acquired by the finite element method and the analytical method.The effects of internal pressure,crack length,inner diameter and thicknessdiameter ratio on the stress intensity factor at the crack tip were studied,and the variation law of stress intensity factor along the wall thickness was studied.The results show that the rise in internal pressure and crack length will increase the stress intensity factor,while the increase of inner diameter and thickness-diameter ratio will decrease the stress intensity factor.However,the stress intensity factor will not change with the increase of diameter when the inner diameter exceeds 500 mm.The stress intensity factor at the outer wall of the pipeline is always higher than that at the inner wall.With the rise in internal pressure,cracks will be initiated from the outer wall of the pipeline.The calculation of stress intensity factor at crack tip based on 1/4 node method,which is easy to operate and high in calculation accuracy,can provide reference for safety evaluation of long-distance pipelines.(10 Figures,6 Tables,24 References)
作者
刘庆刚
张雄飞
王文和
刘玻江
LIU Qinggang;ZHANG Xiongfei;WANG Wenhe;LIU Bojiang(School of Mechanical Engineering,Hebei University of Science and Technology;School of Safety Engineering,Chongqing University of Science and Technology)
出处
《油气储运》
CAS
北大核心
2020年第7期769-776,共8页
Oil & Gas Storage and Transportation
基金
国家自然科学基金资助项目“面向碳捕获与封存的超临界CO2输送管道腐蚀特性及预测模型研究”,51874063。
关键词
长输管道
应力强度因子
奇异单元
1/4节点法
穿透型裂纹
long-distance pipeline
stress intensity factor
singular element
1/4 node method
through-wall crack
