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研究了45CrNiMoVA铁磁钢中心裂纹试样加载条件下疲劳裂纹扩展过程中表面自发射磁信号的变化规律.结果表明:承受疲劳载荷前,各检测线呈现初始磁异变峰特征,切口中心检测线具有最大异变峰-峰值;加载后但疲劳裂纹萌生前,切口位置磁性反转,显示一次异变峰特征,远离切口检测位置磁信号呈现线性;疲劳裂纹扩展过程中,各检测线依次呈现二次异变峰;二次异变峰-峰值和正负峰间斜率可以动态表征疲劳裂纹扩展寿命.基于磁荷概念和等效磁场理论分析了加载条件下疲劳裂纹扩展自发射磁信号行为.
The variation of surface self-emitted magnetic signal during fatigue crack propagation under 456CrNiMoVA ferromagnetic steel was investigated. The results show that before fatigue load, With the maximum peak-to-peak variation. Before loading, but the fatigue crack initiation occurred, the position of the incision was magnetically reversed, showing a characteristic of anomalous peaks and the magnetic signal away from the incision. The magnetic signal showed linearity during fatigue crack growth, Secondly, the peak value of the second mutation and the slope between the positive and negative peaks can dynamically characterize the fatigue crack propagation life.According to the concept of magnetic charge and the equivalent magnetic field theory, the behavior of fatigue crack propagation self-emitted magnetic signal under the loading condition is analyzed.