Flexural Wave Bandgap Property in Thin Plates with Periodic Partial-Constrained-Layer Damping Coverage

摘要

Traditional theory on partial-constrained-layer damping (PCLD) is mainly focused on vibration damping and system loss factors. Bandgap analysis is introduced in thin plates with periodic PCLD coverage. The bandgap dispersion relation is studied first, with the periodic cell consisting of a base plate lattice and the attached structure of certain scales. Each attached structure includes the constraining layer and the viscoelastic layer. Multiple resonant modes of the attached structure make the band-structure curves abundant, and there appear bandgaps within which flexural waves are forbidden to propagate into the plate. Vibration transmission response in the finite structure is also calculated, and the transmission gaps are in good agreement with the bandgaps. Furthermore, by applying the damping characteristic to viscoelastic layers, the vibration attenuation band can be broadened. To illustrate vibration suppression effects of periodic PCLD coverage, together with another two finite models, the transverse vibration transmittances are compared, including a plate attached with periodic lumped resonators, and a sandwich plate with monolithic constrained-layer damping coverage. Results show that much broader attenuation bands are achieved in the plate with periodic PCLD coverage. The bandgap analysis in plates with periodic PCLD coverage can give guidance on suppression of structural vibration.