考虑流体渗透压力的管道焊缝内裂纹扩展流固磁耦合方法

A Fluid-solid-magnetic Coupling Method for the Crack Growth in Pipe Welds Considering the Fluid Permeation Pressure

为实现利用漏磁法检测在役管道焊缝内裂纹动态扩展问题,本研究提出一种考虑流体渗透压力的管道焊缝内裂纹扩展流固磁耦合方法。通过建立管道焊缝内裂纹扩展的流固磁多物理场模型,来构建流固磁多场耦合方程,并进行管道焊缝内裂纹扩展计算,从而实现管道焊缝内裂纹周围计算域网格重构与管道焊缝内裂纹扩展进程中的漏磁场分析。结果表明,流体渗透压力加速了内裂纹扩展进程。与不考虑流体渗透压力相比,考虑流体渗透压力的管道焊缝受到更严重的威胁。同时,考虑流体渗透压力施加的流固磁多场耦合方法更符合工程实际情况。考虑流体渗透压力的管道焊缝内裂纹扩展流固磁耦合方法能较准确地表征在役管道焊缝内裂纹的扩展程度,判断管道焊缝损伤的危险等级,解决流固磁多场耦合作用下管道焊缝内裂纹扩展表征与评价问题。

Aiming at detecting the dynamic crack growth in the weld of the in-service pipeline by magnetic flux leakage method,a fluid-solid-magnetic coupling method considering the fluid permeation pressure was proposed.Through establishing the fluid-solid-magnetic field model in pipeline weld,the coupling equation of fluid-solid magnetic multi-field could be constructed,and the crack propagation in pipeline weld could be calculated,which contribute to the mesh reconstruction around the cracks and the analysis of the leakage magnetic field in the process of crack propagation in the pipeline weld.The results indicated that the the process of internal crack growth was accelerated by the fluid osmotic pressure.The pipe welds considering the fluid permeation pressure were threatened by more serious danger than that without the fluid permeation pressure.Meanwhile,the fluid-solid-magnetic multi-field coupling method considering the fluid permeation pressure was more suitable for the practical engineering,which could accurately characterize the degree of the crack growth in pipe welds,judge the dangerous grade of the weld damage in pipelines.And it has provided a more effective way for characterization and evaluation of the crack growth in pipe welds under fluid-solid magnetic multi-field coupling condition.