Numerical Simulation of Nonlinear Dynamic Responses of Beams Laminated with Giant Magnetostrictive Actuators

摘要

This paper presents some simulation results of nonlinear dynamic responses for a laminated composite beam embedded by actuators of the giant magnetostrictive material (Terfenol-D) subjected to external magnetic fields, where the giant magnetostrictive materials utilizing the realignment of magnetic moments in response to applied magnetic fields generate nonlinear strains and forces significantly larger than those generated by other smart materials. To utilize the full potential application of the materials in the function and safety designs, e.g., active control of vibrations, the analysis of dynamic responses is requested in the designs as accurately as possible on the basis of those inherent nonlineary constitutive relations among stain, force and applied magnetic field existed in the materials. Here, a numerical code for the nonlinear vibration of laminated beams is proposed on the basis of a nonlinearly coupling constitutive model which fully behaves for the characteristics what are measured in experiments. It is found from this code that the natural frequency of the laminated beams changes with both the bias magnetic field and the pre-stresses, and the dynamic responses excited by an alternating magnetic field of simple harmonic form display strong nonlinear characteristics, for example, the frequency multiplication and the ultrahar-monic resonance phenomena.