Experimental characterization and modeling of a new bulk multi-mode magnetostrictive actuator

In this paper, an analytical model of a new bulk magnetostrictive actuator in three modes-longitudinal, bending, and torsional-are examined. The magnetostrictive material considered is a cylindrical vanadium permendur. This actuator is capable of operating in the mentioned modes both independently and in combination. Three constant magnetic fields are used to actuate the device in axial, bending, and torsional modes, and the calculation of each magnetostrictive coefficient d_ij​ is performed by considering all magnetic fields. The longitudinal deformation is applied through the Joule effect by stimulating the magnetostrictive material with a coaxial coil surrounding the material. The torsional mode is implemented via the Wiedeman effect by passing an electric current through a wire inside the magnetostrictive material. For the bending mode, the stimulation is achieved by applying a magnetic field on a surface of the material using a magnetic coupler. The actuator modeling is conducted using classical magnetostrictive equations, and the magnetostriction coefficients are modified for the excitation magnetic fields. Experimental tests are conducted to measure the coefficients. Ultimately, the magnetostrictive deformations in three modes are precisely refined and presented using nonlinear regression relationships.