Establishment of Simulation Methodology for Fabrication of High Performance Magnet

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The objective of this research project is to establish a simulation scheme for fabrication of high performance magnets ; the higher the magnetic performance, the smaller the motor itself. However, there has been no scientific methodology for predicting or determining the optimum process for high magnetic performance. The concrete objectives are as follows :1) Establish a magneto-Cosserat continuum theory and a scheme based on this theory for simulating magnetic alignment during compaction of NdFeB magnetic powder in magnetic filed2) Carry out simulation based on paniculate modeling by developing a model that describes characteristics of NdFeB powder; thus compare with results of experiment on compaction in magnetic field.3) Investigate and study the relationship between magnetic alignment and conditions of compaction in magnetic field. The obtained results are as follows :1) Based on the determined parameters in the developed magneto-Cosserat theoy, we developed a simulation scheme tha … More t incorporated a model for describing the magnetic field that is induced by the magnetized particles. We then simulated compaction of NdFeB powder in magnetic field and found that under the applied magnetic field the effect of the field due to the magnetized particles is not influential, while thisgives quite a large effect on powder behvior when the applied magnetic field is removed. It was also observed that up to a relative density of 0.4 the density was higher at the upper part of the compact and lower at the bottom part; this agreed with experimental results.2) For a case where an initial density variation was given in the simulation, the magnetic alignment, which was best just after application of a magnetic field, became worse as compaction proceeded; this is in good agreement with experimental result.3) In-situ observation of the behavior of magnetic powder during compaction in an applied magnetic field revealed that the displacement of the particles were continuous and that the applied magnetic field displaced the powder more significantly near the bottom part of the powder.4) After compaction up to a relative density of 0.4, the density at the upper part was higher in compaction in magnetic field than in without magnetic field.Development of 3-D simulation scheme, which was one of the objectives, was not realized. This should be done for future work, so that actual application will become possible. Less