载荷作用下管道漏磁内检测信号定量化研究

管道漏磁内检测技术是国际公认的长输油气管道安全维护的最有效方法。为解决载荷作用下长输油气管道漏磁内检测信号定量化问题，本文基于J-A理论建立了改进的三维磁荷数学模型，分析了管道缺陷在内压作用下的磁力学效应对漏磁信号的影响规律，研究了外部载荷作用下缺陷尺寸对漏磁信号影响规律，并通过系统的实验验证了理论模型的正确性。研究结果表明：管道内压增加，材料磁化强度减小，漏磁信号径向分量和轴向分量呈指数函数下降规律；漏磁信号径向分量峰值和轴向分量极大值随着缺陷深度增加而增加，增长率逐渐降低，特征值分别变化6.5%和14.7%;径向分量峰值增长率随长度增加而逐渐降低，轴向极大值线性减小，特征值分别变化21.0%和36.8%,轴向分量对缺陷深度和长度变化更敏感。

Quantization of pipeline magnetic flux leakage detection signal under load

Pipeline magnetic flux leakage internal detection technology is internationally recognized as the most effective method for safetymaintenance of long-distance oil and gas pipelines. To solve the problem of quantifying the internal detection signal of magnetic fluxleakage in long-distance oil and gas pipelines under load, an improved three-dimensional magnetic charge mathematical model isformulated, which is based on the J-A theory. The influence of the magnetomechanical influence of pipeline defects on the magnetic fluxleakage signal under internal pressure is analyzed. The influence law of the defect size on the magnetic flux leakage signal under theaction of external load is studied, and the correctness of the theoretical model is evaluated through systematic experiments. Researchresults show that the internal pressure of the pipeline increases, the magnetization of the material decreases, and the radial and axialcomponents of the magnetic flux leakage signal decrease exponentially. The peak value of the radial component and the maximum axialcomponent of the magnetic flux leakage signal increase with the depth of the defect. The growth rate gradually decreases, and theeigenvalue changes by 6. 5% and 14. 7% , respectively. The peak growth rate of the radial component gradually decreases with theincrease in length, and the axial maximum value decreases linearly. The eigenvalue changes by 21. 0% and 36. 8% , respectively. Theaxial component is more sensitive to changes in defect depth and length.