基于Kp微扰算法的磁场中MMM信号特征的研究

金属磁记忆(MMM)法可以对铁磁性金属构件微观损伤区域进行早期预判和评估,但是磁记忆信号很容易受到外界强磁场的干扰,给检测结果带来偏差。为研究磁场强度对磁记忆信号的影响规律,采用Kp微扰算法,在K空间,通过有效玻尔磁子数p建立多元超原胞磁力学模型,计算在外界磁场作用下,磁力学定量变化关系。研究结果表明,在外界磁场作用下,电子轨道运动增强,晶格结构发生畸变,原子磁矩增大。当磁场较小时,磁记忆信号随外界磁场强度增大而线性增大;当磁场强度达到临界值时,原子磁矩近似等于独立原子的磁矩,磁记忆信号趋于定值;当磁场强度大于临界值以后,应力集中区的磁记忆信号将被磁场覆盖。磁记忆检测实验结果与理论分析结果具有很好的一致性。

Study on the MMM signal characteristics in magnetic field based on Kp perturbation algorithm

The metal magnetic memory (MMM) method can be used to predict and evaluate the micro damage region of ferromagnetic metal components in early stage; however, the magnetic memory signal is easily disturbed by external strong magnetic field, which can lead to the deviation of the detection result. In order to study the influence rule of magnetic field intensity on magnetic memory signal, the Kp perturbation algorithm is used in this paper, the multi primary cell magnetic mechanical model is established based on the number of effective Bohr magnetons p in the K space, and the quantitative changing relationship of magnetic mechanics under the action of external magnetic field is calculated. The research results show that under the action of external magnetic field, the electron orbit motion is strengthened, the crystal lattice structure is distorted, and the magnetic moment of the atom is increased. When the magnetic field is small, the magnetic memory signal increases with the increasing of the external magnetic field intensity linearly; When the magnetic field intensity reaches a critical value, the magnetic moment of the atom is approximately equal to the magnetic moment of the independent atom, and the magnetic memory signal tends to be a constant value; When the magnetic field intensity is greater than the critical value, the magnetic memory signal of the stress concentration area will be covered by the magnetic field. The experiment results of the magnetic memory testing obtained in this paper and theoretical analysis results have very good consistence.