Enhancement of Magnetostriction in Internally-Biased Terfenol-D 2-2 Composites

A key issue in the fabrication of Terfenol-D 2-2 composites with internal magnetic field biasing is the selection of appropriate constituent materials to obtain high magnetostriction while keeping optimum magnetomechanical properties. The fabrication process is costly and time consuming and, therefore, numerical methods to predict their properties are useful. In this paper, finite element analysis (FEA) of the magnetostriction of such composites has been carried out using the commercial package ABAQUS. It has been shown that composites fabricated using Nd₂Fe₁₄B for the permanent magnetic material layers possess the highest internal fields within the Terfenol-D layers, although the overall strain of these composites is limited to approximately 800 times 10^-6 due to the high elastic modulus of Nd₂Fe₁₄B. Simulations showed that the strain can be enhanced by choosing a different material with a lower elastic modulus for the permanent magnetic layer even though the internal field is lower. The simulations showed that the strain can increase by 12% if the Nd₂Fe₁₄B layer is substituted by SmCo₅; by 23 % if it is substituted by Sm₂Co₁₇; and by 35 % if it is substituted by Alnico.