Viscously Damped Dynamic Absorbers of Conventional and Novel Design.
PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB
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The behavior of dynamic vibration absorbers of conventional and novel design has been investigated experimentally and found to compare closely with prediction. The dynamic absorbers were employed to suppress the transmissibility at resonance across a one-degree-of-freedom primary system. Initially considered was a dynamic absorber with a conventional mass-spring-dashpot configuration the primary system was undamped. Subsequently considered were 1 so-called dual dynamic absorbers, and 2 a single, nominally undamped absorber, or two such absorbers, attached to the primary system after it had been damped heavily. The dual absorbers -- a conventional viscously damped absorber used in parallel with a less massive undamped absorber -- introduced a pronounced transmissibility trough without the appearance of unwanted compensating peaks at lower and higher frequencies. The attachment of a nominally undamped absorber to the heavily damped primary system also introduced a pronounced trough without giving rise to compensating peaks. Further, the attachment of two such absorbers introduced pronounced troughs at two frequencies that could be varied independently of one another. Thus, the novel absorber systems considered here behaved as mechanical notch filters, providing at specific low frequencies a high degree of isolation that other passive systems cannot duplicate without exhibiting a marked loss in isolation at neighboring frequencies.