The residual magnetization technique is a new method for detecting stress concentration zones (SCZs) in ferromagnetic materials. Local rising of stress at SCZs, such as cracks, results in the development of local elastic and plastic deformation. The two deformation regimes produce different magnetic characteristics, which have competing effects on self-magnetic-flux-leakage signals. In the present research, samples with three different groove depths were subjected to different tensile stress levels. A surface scanning system was used to record the variation of magnetic signals at grooves of varying depth under steadily increasing stress conditions. The results show that elastic deformation increases peak-to-peak values of normal magnetic components and a maximum gradient of the normal magnetic component in the direction of applied stress, while the development of local plastic deformation reduces signal intensity at groove locations. The magnetic object (MO) model is used to explain the mechanism for excess flux leakage field at SCZs as being due to the conversion of magnetoelastic energy—introduced by the application of tensile stress up to the local yield point—into magnetostatic surface poles that are sensed as an increase in the normal component of leakage.

中文翻译：

---

应力集中区的应力诱导自磁漏

剩磁技术是一种检测铁磁材料应力集中区（SCZ）的新方法。SCZ 处应力的局部升高，例如裂纹，导致局部弹性和塑性变形的发展。两种变形方式产生不同的磁特性，这对自漏磁通信号具有竞争性影响。在本研究中，具有三种不同凹槽深度的样品受到不同的拉伸应力水平。表面扫描系统用于记录在稳定增加的应力条件下不同深度的凹槽处磁信号的变化。结果表明，弹性变形增加了法向磁分量的峰峰值和法向磁分量在施加应力方向上的最大梯度，而局部塑性变形的发展降低了凹槽位置的信号强度。磁性物体 (MO) 模型用于解释在 SCZ 处产生过量磁通泄漏场的机制，这是由于磁弹性能（通过施加达到局部屈服点的拉应力引入）转化为静磁表面极点而引起的。感觉为泄漏的正常分量增加。