Semi-Analytical Method for Evaluating Magnetic Properties of SMC Based on Homogenization Model

A semi-analytical method is presented in this article for evaluating the magnetic properties of soft magnetic composites (SMCs), and the quantitative structure-activity relationship between microstructural parameters and macroscopic magnetic properties of SMCs is investigated. First, a new homogenization model is developed with the objective of characterizing the microstructure of SMC. The concepts of insulating layer, pore, and surface roughness structure are introduced. Meanwhile, the thickness of the insulating layer is calculated using the least square, the mass density and volume fraction of the particles are determined using a discrete element method (DEM), and the surface roughness of the particles is characterized using a periodic square waveform. Then, by analyzing the relationship between the microstructural parameters and magnetic properties, analytical expressions are derived to realize the evaluation of the macroscopic permeability and eddy current loss of the SMC. Finally, the SMC-prepared samples are tested by the dc magnetization method and ring sample method, respectively, to verify the reliability of the proposed semi-analytical method by comparing the experimental and evaluation results.