Amplitude-dependent damping characteristics of all-composite sandwich plates with a foam-filled hexagon honeycomb core

The amplitude-dependent damping characteristics of all-composite sandwich (ACS) plates with a hexagon honeycomb core (HHC) filled by soft foam (SF) are investigated both experimentally and theoretically. Initially, the fabrication procedure of HHC-SF-ACS plate specimens is proposed. Vibration tests are carried out on those plate specimens with different excitation amplitudes, where the amplitude-dependent damping phenomenon is observed. Then, by employing Reddy's high-order shear deformation theory, Hamilton's principle, and finite element method, the so-lutions of nonlinear fundamental frequencies, mode shapes, and damping ratios of HHC-SF-ACS plates are obtained theoretically. Following the identification of the key fitting variables for foam-filled HHC, comprehensive comparisons of the predicted and measured results are per-formed to validate the proposed model. Finally, the influences of critical material and geometry parameters of SF on the amplitude-dependent damping performance are discussed. It is found that the damping property of the composite plates can be improved by increasing either Young's or shear moduli of foam material, but is more sensitive to shear modulus. Besides, the increase in filling ratio of SF also helps to improve the damping performance significantly.