Demagnetization properties study on NdFeB permanent magnets under impact load

Abstract Sintered NdFeB materials are more and more widely used in the military field because of their excellent magnetic field performance and cost performance. The demagnetization of materials caused by the impact was discussed in this paper to provide a theoretical basis for the application of NdFeB. Firstly, the experimental platform for the demagnetization of material under impact was built, and the corresponding load of impact was calibrated by using the thin-film piezoelectric sensor. In the experiment, the changes in the magnetic field were converted into an electrical signal that was easy to observe. The curves for the changes of the induced electromotive force and magnetic flux were obtained under different velocities of impact. Then, a new impact demagnetization model was proposed combined with the experimental results and the demagnetization process of sintered NdFeB materials under an external magnetic field. The model was based on the stress knee-point hypothesis and irreversible deterioration hypothesis. Finally, the co-simulation model was established in this paper, and the identified parameters were substituted into the model for numerical calculation. The validity of the model and the accuracy of parameter selection were verified by comparing the calculation results with the experimental results.