外磁场激励下管道弱磁应力内检测特性研究

弱磁应力检测技术支持非接触在线应力损伤检测,在长输油气管道应力内检测技术领域具有巨大的应用潜力。但弱磁信号微弱，易受外界环境干扰，检测结果易出现偏差。为加强弱磁信号的检测能力，基于铁磁材料的微观特性，建立了外磁场弱磁应力检测模型，获得了弱磁信号强度随外磁场强度与施加应力的变化规律，描述了外磁场对弱磁应力检测信号的激励特性，并进行了系统的实验研究。结果表明，弱磁信号的切向峰值与法向零点均位于应力集中区的中心位置，且不随应力与外磁场的变化而发生波动；弱磁信号切向峰值与法向峰峰值随外磁场与应力的增加而增大；外磁场对弱磁应力检测信号的激励作用随外磁场的增加先增大后减小。

Study on of Internal Characteristics Detection of Weak Magnetic Stress in Pipelines under Excitation of External Magnetic Field

The weak magnetic stress detection technology supports non?contact online detection of stress damage. It has great application potential in the field of long?distance oil and gas pipeline stress detection technology. However, as the weak magnetic signal is weak and easy to be interfered by the external environment,the detection result is prone to deviation.In order to strengthen the detection ability of weak magnetic signals, based on the microscopic characteristics of ferromagnetic materials, a weak magnetic stress detection model under an external magnetic field was established, and the change law of weak magnetic signal strength with the increase of external magnetic field strength and applied stress was obtained.The excitation characteristics of the external magnetic field to the weak magnetic stress detection signal were described,and a systematic experimental study was conductd.The results show that the tangential peak value and the normal zero point of the weak magnetic signal are located in the center of the stress concentration area, and do not fluctuate with the change of the stress and the external magnetic field.The tangential peak value and the normal peak?peak of the weak magnetic signal increase with the increase of the external magnetic field and stress. As the external magnetic field increases, the excitation effect of the external magnetic field on the weak magnetic stress detection signal increases first and then decreases.