高载旋转弯曲疲劳损伤的磁记忆检测

为寻找高载旋转弯曲疲劳破坏前的特征信号,基于磁机械效应及磁场叠加原理进行理论研究,在此基础上,对带环形缺陷的45号钢试件进行高载旋转弯曲疲劳试验,研究疲劳过程中试件表面的磁信号的法向分量的分布变化.理论分析表明,疲劳裂纹附近的磁信号分布随裂纹扩展而变化.实验结果显示在进入裂纹快速扩展前后,缺口两边的磁信号大小顺序发生变化;名义应力及应力集中系数、环境磁场和提离值影响检测效果,但有对应的解决方法.磁记忆技术用于高载旋转弯曲疲劳损伤检测是可行的.

Magnetic memory testing for high load rotating bending fatigue damage

In order to research the character signal of high load rotating bending fatigue before the fracture of specimens,the theoretical study was conducted based on magnetomechanical effect and magnetic field superposition,and the high load rotating bending fatigue experiment was carried out on 45#steel specimens with annular notch.The distribution variation of normal magnetic signals was analyzed.Theoretical analysis indicates that the magnetic signal distribution near the fatigue crack changes as the crack propagates.Experimental results show that,before and after the rapid crack propagation,the size order of signal near the crack changes. The detection effect is impacted by nominal stress,stress concentration factor,environmental magnetic field and sensor liftoff,then the corresponding strategies are put forward.So it is feasible to detect high load rotating bending fatigue damage using metal magnetic memory technique.