Experimental investigations of lightweight structures with fluidically actuated Compressible Constrained Layer Damping

Abstract

Since strength, stiffness and damping are coupled design variables of fibre reinforced plastics, the lightweight-focused design often leads to a problematic vibration susceptibility of the developed components. This article presents an experimental proof-of-concept of fluidically controlled Compressible Constrained Layer Damping, a novel, semi-active, lightweight-compatible solution for vibration mitigation without explicit actuators.The proposed actuating principle is based on structural cavities generating forces and slight structural deformations when supplied with fluid. The cavities encapsulate compressible, low profile viscoelastic layers operating according to the principle of the Constrained Layer Damping. The intended actuation mechanism controls the thickness of the viscoelastic layers and thus the material properties and the amount of the vibration-induced shear deformation.The described actuating principle is experimentally investigated on a sample composite structure which was excited using an electrodynamic shaker while the vibration response was measured using a laser scanning vibrometer. The obtained results for monofrequent excitation revealed that the compression-driven adjustment allows mobility changes in the range up to 15.8 dB and the mobility can be decreased up to 24.3 dB compared to the untreated base structure due to a shift of the resonance peaks frequency. A second indicator – the adaptive dissipative power – was analysed showing a complex dependency upon the negative actuation pressure and offering a wide adjustment capability.