Controllability of Conducting Structures Using Magentoelastic Damping

Abstract

Magnetoelastic interactions in conducting beams arc studied experimentally and numerically as a possible means for active vibration suppression mechanism in structural control. The experimental apparatus involves a cantilevered beam made of flexiglass which is placed in between two poles of a magnet. The desired effect of magnetoelastic interaction in the beam is provided by a concentric coil attached to the face of the beam and the magnetic field generated by the horn magnet. The electromagnetic damping control system works based on the concept of negative feedback. The vibration is shown to be reduced significantly although only a small amount of electric current is supplied to the coil. The experiment is then analytically modeled using the Faraday's law and the resulting electromotive force acting on the beam and cast into a nonlinear initial boundary value problem. The resulting nonlinear problem is then solved numerically using the finite difference method. Experimental results are consistent with the analytical study and demonstrate the controllability of beams using the magnetoelastic interaction. An effective damping factor due to the magnetic damping is suggested based on the energy balance. Promises and limitations of the proposed control strategy are also discussed.