Passive vibration control using viscoelastic and constrained layer beam waveguide absorbers
Horne, Charles T. III
Shin, Young S.
Kim, Kilsoo S.
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Reduction of noise and vibrations within structural systems has been a long standing problem. Recent studies have indicated that waveguide absorbers have been effective in the reduction of noise and vibrations over a broad frequency range. A waveguide absorber is a structure along which vibrational waves can travel. If the waveguide absorber is treated with an energy dissipation scheme, the amplitudes of the waves will decrease as they travel along the waveguide absorber. The test structure consisted of a rectangular aluminum plate with clamped boundary conditions. A finite element analysis approach theoretically predicted the test structure's mode shapes and modal strain energies. An experimental modal survey was conducted to compare with the theoretically predicted mode shapes and natural frequencies. The mode shapes and modal strain energies determined the optimum locations of the waveguide absorbers and their orientation on the test structure. The frequency range of interest and mode sh'pes determined the required number of waveguide absorbers. Experiments were conducted using viscoelastic and constrained layer beam waveguide absorbers over a 2000 Hertz frequency range. Significant reduction of the test structure's frequency response was demonstrated through the effective use of multiple beam waveguide absorbers.
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