受环境侵蚀油气管道轴向拉伸行为数值模拟  

Numerical simulation on uniaxial tension behavior of environmentally eroded pipelines

作　　者：刘锋 杨玉超[1] 席丰[2] LIU Feng;YANG Yuchao;XI Feng(Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation, Shandong University of Science and Technology, Qingdao 266590, China;School of Civil Engineering, Shandong Jianzhu University, Jinan 250101, China)

机构地区：[1]山东科技大学山东省土木工程防灾减灾重点实验室,山东青岛266590 [2]山东建筑大学土木工程学院,山东济南250101

出　　处：《中国石油大学学报（自然科学版）》2020年第6期116-123,共8页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(52078283;11672165)

摘　　要：基于蒙特卡洛理论通过数值模拟方法研究锈蚀率和壁厚分布场的标准差对管道宏观力学行为的影响机制。首先基于随机理论建立目标锈蚀率为15%、45%和70%,标准差为0.02、0.06和0.10 mm,共计2700个管道壁厚的非平稳随机场;然后将壁厚随机场映射为有限元模型单元厚度,应用考虑损伤的材料本构模型,进行对应数量的数值拉伸试验。结果表明管道的锈蚀率和管壁分布场的标准差共同主导管道的宏观拉伸力学行为;相同标准差下,较高锈蚀率对应的管壁更容易在薄弱位置产生应力集中,导致管道失效;相同锈蚀率下标准差的提高将加剧壁厚分布不均匀性,较低的拉伸荷载即引起薄弱位置产生损伤,并导致裂纹扩展角度和发展路径的随机性,从而降低管道强度和断裂应变。To understand the influence mechanism of the corrosion rate and the standard variance of the random field on the thickness of the corroded pipelines related with the macroscopic mechanical properties of the pipelines,a computational procedure based on the Monte Carlo simulation method was developed in this study.A non-stationary stochastic field related with 2700 random samples,which contains three corrosion rates of 15%,45%and 70%,and each corrosion rate with three variances of 0.02 mm,0.06 mm and 0.10 mm were generated.Subsequently,the wall thickness of the random fields was mapped to the finite element model.The constitutive model considering damage was adopted to perform the numerical tension experiment with the corresponding number of samples.The results show that,the corrosion rate and the standard variance of the random field of the thickness along the pipe surface collaboratively dominate the macroscopic mechanical properties of the corroded specimen.Under the same standard deviation,the wall corresponding to the higher corrosion rate is more likely to cause stress concentration at the weak position,which makes the pipe more easily to fail.Under the same corrosion rate,the increase of the standard deviation will aggravate the unevenness of the wall thickness distribution,and then the lower tensile load will cause damage at weak locations and lead to randomness of the crack propagation path,thereby reducing the strength and fracture strain of the pipe.

关 键 词：管道 锈蚀 拉伸性能 蒙特卡洛模拟 非线性分析 

分 类 号：O341[理学—固体力学]