地磁场环境下烧结钕铁硼疲劳破坏在线监测方法研究

作为一种典型的硬磁材料,烧结钕铁硼在疲劳断裂时具有突发性、不确定性和紧迫性等特性,难以对其疲劳破坏变化过程进行在线监测.为了实现对烧结钕铁硼零构件在长期服役期间疲劳破坏全过程的在线监测,论文根据力磁耦合效应构建了地磁场环境下烧结钕铁硼的疲劳状态演变方程,将烧结钕铁硼的磁感应强度值作为描述疲劳破坏的状态参数.利用高精度测...

Research on On-line Monitoring Method of Sintered Nd-Fe-B Fatigue Damage in Geomagnetic Field

Sintered Nd-Fe-B which is a typical hard magnetic material, crises characterized by unexpectedness, uncertainty, and urgency during fatigue cracking. Therefore, it is difficult to monitor its fatigue damage propagation process online. In order to realize the online monitoring the whole process of fatigue damage expansion for sintered Nd-Fe-b during its long-time service, the fatigue state evolution equation of sintered Nd-Fe-B under the geomagnetic field environment is constructed by utilizing coupling effects of stress and magnetic. The magnetic induction value is used as the state parameter to describe the fatigue damage. The magnetic induction intensity of the weak magnetic which is collected by high precision magnetic sensor is used to monitor the fatigue damage prop-agation process online. The fatigue test results show that: it can accurately predict the point of fracture in time during fatigue damage propagation process for sintered Nd-Fe-B by the trends of the magnetic induction intensity value and the residual value of the polynomial fitting curve. Meanwhile, the variation of magnetic induction signal curve reflects the whole process of Nd-Fe-B fatigue damage propagation under stress without distortion.