Nonlinear Magnetostrictive Actuator and Sensor

Application ID: 9726

Magnetostrictive material exhibits free strain under the influence of magnetic field. It also exhibits a stress-induced change in magnetization in the presence of a bias magnetic field. In this tutorial we model a quasi-static transducer which has a steel housing enclosing a drive coil. A magnetostrictive material is placed in the core. Magnetic and structural interactions between the magnetostrictive material with the transducer housing made of magnetic steel is modeled via using bidirectionally coupled nonlinear constitutive relations. The nonlinearity is incorporated by using interpolated values of material data which is used to express the magnetic field and magnetostriction as a function of magnetic flux density and mechanical stress.

In this 2D axisymmetry model the nonlinear relationship between stress, strain, magnetic flux density and magnetic field is shown by performing different case studies which highlight the effect of preload in actuator characterization and bias coil current in sensor characterization. The actuator characterization involves finding the transducer displacement as a function of coil current for different preloads. The sensor characterization involves finding the change in magnetic flux density in the magnetostrictive material as a function of axial load on the transducer for different DC bias coil current. Related concepts such as blocked force of an actuator and Delta-E (magnetic field induced softening and stiffening) effect are also covered.