Vibration control of beams using electro-magnetic compressional damping treatment

A new class of structural damping treatments is introduced This class is th e electromagnetic clamping treatment (EMDT) which relies in its operation o n a viscoelastic damping layer sandwiched between two magnetic layers. Inte raction between the magnets generates magnetic forces that enhance the comp ressional damping mechanism of the viscoelastic layer: With proper tuning o f the magnetic forces, in response to the structural vibration, undesirable resonances and catastrophic failures can be avoided. The fundamentals and the underlying phenomena associated with the EMDT are investigated theoreti cally and experimentally. A finite element model is developed to describe t he interaction between the dynamics of flexible beams, the viscoelastic dam ping layer and the magnetic layers. The validity of the developed finite el ement model is checked experimentally using aluminum beams treated with EMD T patches. The beam/EMDT system is subjected to sinusoidal excitations and its multi-mode response is monitored when the magnetic layers are activated or not. Several control strategies are considered to activate the magnetic layers including simple PD controllers. The performance of the uncontrolle d and controlled system is determined at various operating conditions. Atte nuation of 49.4 percent is obtained for the amplitude of first mode of vibr ation (5.2 Hz) with control voltage of 0.2 volts. The attenuation increases to 72.56 percent for the second mode of vibration (28.6 Hz) with a control voltage of 1.68 volts. Comparisons with conventional Passive Constrained L ayer Damping (PCLD) treatments emphasize the potential of the EMDT treatmen t as an effective means for controlling structural vibrations. [S0739-3717( oo)00603-6].