管道磁记忆检测信号与缺陷应力关系的有限元仿真

为了实现对管道磁记忆检测信号与缺陷应力关系的定量研究,建立了含腐蚀缺陷管道的二维有限元仿真模型,给出了应力-磁导率耦合数学模型以及管体应力和地磁场求解控制方程。首先利用ANSYS的应力分布功能,计算求得管体在4.5MPa内压下的应力强度分布,然后根据应力-磁导率数学模型计算求得管体外侧的地磁场分布,表明管体应力与磁导率之间具有一定的耦合关系,证实了有限元模拟技术可以准确捕捉到管体缺陷处的磁应力信号,进而判定管道的缺陷特征。

FEA of the relationship between MMM signal and stress in pipeline inspection

2D Finite Element Analysis (FEA) is performed in order to study the relationship between the Metal Magnetic Memory (MMM) signal and the stress, and the stress-magnetic permeability coupling model and the governing equation for pipe stress and earth magnetic fi eld are applied. First, utilizing the stress distribution calculation function provided by ANSYS, the stress strength distribution of the pipe under 4.5 MPa is computed, then, the earth magnetic fi eld is calculated with the stress-magnetic permeability coupling model. The results show that the stress and the magnetic permeability are related and FEA is capable for detecting the stress signal, hence recognizing the pipe defects.