Study on damage constitutive model of sintered NdFeB under impact

Compared with a large number of studies on the magnetic field properties of sintered NdFeB, the study on its dynamic mechanical behavior is insufficient, which restricts the further development of materials in a dynamic environment. To break through the above situation, the dynamic mechanical property of sintered NdFeB materials is discussed based on the split-Hopkinson pressure bar (SHPB) experimental principle. The experimental data show that the material has obvious strain rate correlation characteristics at medium and high strain rates. To describe the dynamic behavior characteristics of material so as to better guide engineering practice, a new dynamic compression damage constitutive model of sintered NdFeB is proposed. The damage is defined on the basis of Weibull distribution. In addition, the wing crack growth model considering the crack gap is established. Thus the damage evolution model can be obtained. Combining the damage evolution model with Zhu-Wang-Tang (ZWT) constitutive model, the dynamic damage ZWT constitutive model of sintered NdFeB under one-dimensional impact load is constructed. The key parameters of the model are identified according to the experimental data and the non-linear phenomenon of the stress-strain curve of sintered NdFeB under one-dimensional impact load can be well explained.