Vibration characteristics of MR cantilever sandwich beams: experimental study

Abstract

The concept of vibration controllability with smart fluids within flexible structures hasbeen of significant interest in the past two decades. Although much research has been doneon structures with embedded electrorheological (ER) fluids, there has been littleinvestigation of magnetorheological (MR) fluid adaptive structures. In particular, a body ofresearch on the experimental work of cantilever MR beams is still lacking. Thisexperimental study investigates the controllability of vibration characteristics ofmagnetorheological cantilever sandwich beams. These adaptive structures areproduced by embedding an MR fluid core between two elastic layers. The structuralbehaviour of the MR beams can be varied by applying an external magnetic field toactivate the MR fluid. The stiffness and damping structural characteristics arecontrolled, demonstrating vibration suppression capabilities of MR fluids as structuralelements. MR beams were fabricated with two different materials for comparisonpurposes. Diverse excitation methods were considered as well as a range of magneticfield intensities and configurations. Moreover, the cantilever MR beams weretested in horizontal and vertical configurations. The effects of partial and fullactivation of the MR beams were outlined based on the results obtained. Thecontrollability of the beam’s vibration response was observed in the form of variations invibration amplitudes and shifts in magnitudes of the resonant natural frequency.