The Forced Response and Damping Characteristics of a Cantilever Beam with a Thick Damping Layer.
DEFENCE RESEARCH ESTABLISHMENT ATLANTIC DARTMOUTH (NOVA SCOTIA)
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This technical memorandum describes the vibration analysis of a steel cantilever beam. The beam was 649 mm long, 204 mm wide and 9.5 mm thick with a free viscoelastic damping layer 27 mm thick EAR Isodamp C-1002 bonded to one surface. Predictions of composite loss factor and response were made at forcing frequencies between 10 Hz and 3000 Hz using a direct frequency response capability recently developed for the DREA in-house finite element code VAST. Analytical results were also obtained with the code PREDC, acquired from the University of Dayton, Ohio. The frequency dependent dynamic mechanical material properties, used in the VAST and PREDC analyses, were measured at DREA using a forced vibration non- resonant method. The VAST forced response vibration analysis was in good agreement with experiment. Above 500 Hz, the system composite loss factors predicted with the PREDC code were significantly below the measured loss factors and those predicted by the VAST code. This is attributed to the more complicated deformation of the damping layer, predicted by the finite element model, but not accounted for by the Euler-Bernoulli beam formulation used in the PREDC code. MM
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