Online monitoring method for fatigue crack damage propagation of sintered neodymium iron boron

The invention discloses an online monitoring method for fatigue crack damage propagation of sintered neodymium iron boron, and relates to the technical field of nondestructive testing. By means of anonline monitor provided with a high-precision magnetic sensor, on the premise that the monitoring accuracy is guaranteed, the real-time online monitoring process of the fatigue damage propagation process of brittle materials such as sintered neodymium iron boron can be achieved. Meanwhile, the requirement for the monitoring environment is low, and application scenes are wide. According to the monitoring method provided by the invention, the stress concentration condition of sintered neodymium iron boron before fatigue fracture can be reflected on the premise of not damaging the structural integrity of the sintered neodymium iron boron, qualitative analysis is performed on the early fatigue damage accumulation process, the occurrence of sudden brittle fatigue fracture behavior of the sintered neodymium iron boron c