An initial experimental investigation into the change in magnetic induction of a Terfenol-D rod due to external stress

Magnetostriction is typically used for actuation and its reverse effect, known as the magnetomechanical effect, for sensing. Giant magnetostrictive materials, such as Terfenol-D, are capable of producing large strains when placed in a magnetic field and changes in the magnetization on application of an applied stress. The present investigation seeks to explore the novel idea of changing the magnetization of a Terfenol-D rod due to an applied force under a defined pre-stress to investigate the suitability of transferring appreciable amounts of magnetic energy to external media. Experimental investigations have been carried out on a Terfenol-D monolithic rod under different levels of constant pre-stress to quantitatively estimate the change in magnetic induction. It is shown that the change in magnetic induction is very small compared with that for a permanent magnet. Further, the inductive field is dependent on the dynamic behaviour of the Terfenol-D rod.