Effects of stress on the magnetic properties of grain-oriented silicon-iron magnetized in various directions

Mechanical stress has been applied to samples of grain-oriented 3% silicon-iron magnetized at various angles to the rolling direction. The angle between the magnetizing field, H, and the flux density, B, is known to vary considerably and when stress is applied either parallel or perpendicular to the rolling direction of the sheet the deviation between B and H changes according to the magnitude of the stress. The effect can be predicted using a simple energy model and some correlation between the model and experimental measurements is shown. It is explained why the effect should be taken into account when attempting to predict losses from theoretical field distributions in laminated cores assembled from such material.