Constrained-layer damping

About: Constrained-layer damping is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 15758 citations.

Vibration Control of Beams Using Electro-Magnetic Compressional Damping Treatment

Abstract: A new class of structural damping treatments is introduced. This class is the electro-magnetic damping treatment (EMDT) which relies in its operation on a viscoelastic damping layer sandwiched between two magnetic layers. Interaction between the magnets generates magnetic forces that enhance the compressional damping mechanism of the viscoelastic layer. With proper tuning of 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 theoretically and experimentally. A finite element model is developed to describe the interaction between the dynamics of flexible beams, the viscoelastic damping layer and the magnetic layers. The validity of the developed finite element model is checked experimentally using aluminum beams treated with EMDT 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 uncontrolled and controlled system is determined at various operating conditions. Attenuation of 49.4 percent is obtained for the amplitude of. first mode of vibration (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 Layer Damping (PCLD) treatments emphasize the potential of the EMDT treatment as an effective means for controlling structural vibrations.

Mechanical properties for CFRP/damping-material laminates

Abstract: New materials that possess high damping capabilities and have high strength properties have been studied in carbon fiber reinforced plastics (CFRP). These materials are referred to in this article as CFRP/damping-material laminates. The CFRP/damping-material laminates investigated here are composed of a unidirectional carbon/epoxy prepreg sheet and a polyethylene-based damping material sheet used as an interleaf. Cantilever beam tests revealed the high damping properties of these laminates. Loss factor values for these composites are 5 to 50 times as large as that for conventional CFRP. These values could be predicted by using the analysis constrained layer damping treantment, except for two specimens. Also, the interleaving effect on tensile and compression strength are discussed here