MODAL-ANALYSIS OF FLEXIBLE BEAMS WITH DELAYED RESONATOR VIBRATION ABSORBER - THEORY AND EXPERIMENTS

A recent active vibration absorption method, the Delayed Resonator (DR ) is considered. The DR absorber is implemented on a flexible beam, an d the dynamic features of this structure are studied. An analytical mo del of the system is developed in order to predict the experimental fi ndings. Instead of the earlier finite difference method, modal co-ordi nate representation is adopted here. In particular, the stability feat ures obtained through analytical and experimental studies are compared . The boundary conditions (BCs), i.e., the beam's clamping structure, dictate the restoring forces on the beam-absorber system, and therefor e, play an important role on the system stability. In the experimental work the results are generated under the present beam BCs. For the an alytical study, however, they have to be carefully formulated. In orde r to reflect the physical reality some unconventional BCs are used on the beam. This forms an important part of the ''modelling'' effort pre sented here. The results obtained concur with the experimental finding s better than the earlier dynamic models which use the finite differen ce method and ideal clamped-clamped BCs. In summary, modal representat ion with the unconventional BCs are suggested as an analytical tool fo r the design of DR absorbers operating on beams. (C) 1998 Academic Pre ss.