The modeling of magnetomechanical sensors in laminated structures

A non-linear magnetomechanical plate model has been developed to predict the magnetic induction, elastic and magnetostrictive strain and mechanical stress in a laminated structure with magnetostrictive and non-magnetic layers under the simultaneous effect of quasi-static mechanical stress and the magnetic field. This model was obtained by coupling classical laminated plate theory to an energy-based statistical magnetomechanical model. The model was used to study a unimorph structure having a magnetostrictive iron-gallium (Galfenol) patch attached to a non-magnetic aluminum substrate. The sensing responses from the patch were obtained for in-plane axial and shear forces as well as bending and twisting moments acting on the unimorph. The effect of the DC bias magnetic field and the ratio of patch thickness to substrate thickness on the sensor performance was studied. The results demonstrate that the model can capture the non-linearity in the magnetomechanical process and the different structural couplings.