基于力磁耦合型的管道电磁应力检测解析模型研究

针对管道应力检测和定量化研究,提出一种基于电磁检测原理的管道应力检测方法。本文以J-A模型为基础,采用分子电流理论建立了管道力磁耦合模型,结合非磁滞条件下铁磁材料磁化曲线,利用管道力磁耦合模型解析计算了磁化方向上外磁场和应力对管壁表面磁场的影响规律,并进行了系统性实验研究。研究结果表明,随应力强度的增加,磁化方向上管道电磁应力检测信号呈现先增大后减小的变化趋势(变化方向翻转),翻转点前后均呈线性关系,但磁场信号变化速率改变,磁力学敏感度发生变化;随着外磁场的增加,在磁化曲线处于磁饱和(磁场强度大于20 KA/m)时,应力对铁磁材料磁化强度影响较小,磁场强度约为5 000 A/m时,应力对磁化强度影响较为显著。

An analytical model of electromagnetic stress detection for pipeline based on magneto-mechanical coupling model

Aiming at the pipeline stress detection and quantitative research, a pipeline stress detection method based on electromagnetic detection principle is proposed. Based on the J-A model and molecular current theory, a mechanical magnetic coupling model of the pipe is formulated. Combined with the magnetization curve of ferromagnetic materials under non-hysteresis condition, the influence of external magnetic field and stress on the magnetic field of the pipe wall in the magnetization direction is calculated by using the mathematical model, and a systematic experimental study is carried out. Results show that with the increase of the stress intensity, the electromagnetic stress detection signal of the pipeline increases firstly. Then, the magnetization direction decreases ( the direction of change is reversed). There is a linear relationship before and after the flip point. However, when the rate of magnetic signal changes, the magneto dynamic sensitivity changes with the increase of external magnetic field. When the magnetization curve is at magnetic saturation (magnetic field intensity is greater than 20 KA/ m), the stress has little effect on the magnetization of ferromagnetic materials. When the magnetic field intensity is about 5 000 A/ m, the stress has more significant effect on the magnetization.