The magnetization and magnetostriction of Tb0.3Dy0.7Fe1.9 fiber actuated epoxy matrix composites

The present work reports the magnetic induction, fiber and matrix internal stresses, and magnetostriction of model continuous, [112] oriented, Tb0.3Dy0.7Fe1.9 fiber actuated epoxy matrix composites as functions of fiber actuator volume fraction and applied magnetic field. The analysis indicates that the thermal mismatch strain resulting from cooling the composite from the matrix curing temperature is effective in concentrating magnetization probability about the transverse [11 (1) over bar] and [(1) over bar 11] directions, which increases the apparent saturation magnetostriction available to a longitudinally applied magnetic field process. The analysis further indicates that the increase in fiber longitudinal compressive stress resulting from the accommodation of an increment of positive fiber magnetostriction increases the fiber magnetoelastic energy in the applied field direction. Therefore, the increased matrix stiffness resulting from a reduction in fiber actuator volume fraction results in a reduced permeability, an increase in the magnetic field strength required for a given level of magnetostriction, and an increase in the magnetic field strength required for saturation. (C) 1997 Elsevier Science S.A.