Modeling effects of varying torsion in magnetized steel

In this paper, we develop a model for magnetization changes in a steel rod under varying torsion in a constant applied magnetic field, At any point on the surface of the rod under torsion, the magnetization changes, in a smal l region about the point, are driven by biaxial stress changes, which are e qual in magnitude, with one stress change tensile and the other compressive , and with the stresses acting at +/-45 degrees with respect to the rod axi s, tangentially to the surface of the rod, In this paper, we demonstrate ho w to extend the "law of approach" of and the energy balance equation to irr eversible magnetization changes under varying torsional stress at constant magnetic field. As an illustration of how the model is used, a prediction i s made showing changes in axial nux density at the surface of the rod when the torsion is cycled five times between zero and a maximum value of torque .