为解决油气管道弯曲应力难以测量而带来的管道变形与屈曲问题,提出了基于磁弹效应的弯曲应力检测方法。首先建立磁弹性应力检测模型,分析磁弹性传感器检测回路中的磁路与阻抗特征关系;其次对弯曲作用下材料内部的应力分布进行研究;最后开展不同情况下Q235钢板弯曲过程中,阻抗随应力变化情况的试验。结果表明,钢板表面阻抗随应力增加呈明显下降趋势,一定应力范围内阻抗与应力具有近似线性的对应关系,距离受力区域一定范围内仍能检测到阻抗随应力的变化。该方法可对管道弯曲应力进行有效检测,试验结果和理论分析具有很好的一致性。

In order to solve the problem of pipeline deformation and buckling caused by the difficulties in measuring the bending stress of oil and gas pipelines, a bending stress detection method based on magneto-elastic effect was proposed. Firstly, the magneto-elastic stress detection model was established. The relationship between magnetic circuit and impedance characteristics in the detection loop of magneto-elastic sensor was also analyzed. Secondly, the stress distribution within the material under bending was studied. Finally, the relationship between the impedance and stress in Q235 steel plate during bending under different conditions was experimentally investigated. Results show that the impedance on the steel plate surface apparently declined with increasing stress and the relationship between impedance and stress within a certain range of stress was approximately linear. Within a certain range of stressed area, the impedance change with stress can be detected. This proposed method can effectively achieve pipe bending stress detection. The experimental results and theoretical analysis are in rather better agreement.