ANSYS模拟点腐蚀管道微裂纹扩展

摘要

On the damaged pipeline caused by pitting corrosion, there exist a lot of micropores and mocrocracks, from which pipelines are fractured and damaged. In order to understand the extending dynamic state of microcracks on the pitting pipelines, control the ex- tension of mierocracks better and lengthen the service life of pipeline, it is very significant to study the distribution, spreading law and expanding rate of microcracks for the research of pipeline serving life. Therefore, combined with the mechanical theories of microc- rack expansion, by means of finite element bases, the two-dimensional finite element model has been constructed by the application of strong analysis function of ANSYS software. This model simulated the expanding path and stress distribution of microcracks in the damaged defaults of pitting corrosion pipeline, and dynamically described the expanding state of cracks when pipeline is loaded and damaged during the operation, and calculated the energy released at the unit length of mierocrack and the stress value distribution of Von Mises. Generally speaking, with the gradual expansion of microcrack, the energy released for its unit length is gradually becom- ing small, taking the trend of gradual reduction.%点腐蚀引起的损伤管道，其表面往往存在许多微孔洞和微裂纹，管道的断裂损坏也常常从微裂纹开始。为了进一步了解点腐蚀管道微裂纹扩展动态，更好地控制微裂纹的扩展，进而延长管道使用寿命，研究微裂纹的分布情况、扩展规律和扩展速率对于管道的寿命研究有着重要的意义。结合管道微裂纹扩展的力学理论知识、借助有限元基础、应用ANSYS软件强大的分析功能，建立了二维有限元模型，模拟了输气管道点腐蚀损伤缺陷中微裂纹的扩展路径和应力分布，动态地描述了输气管道在运行过程中加载受损时微裂纹的扩展情况，计算出了微裂纹单位长度所释放出来的能量和VonMises应力值分布。一般来说．随着微裂纹的逐步扩展，其单位长度所释放出来的能量逐渐减小、呈递减趋势。