Effects of thickness and delamination on the damping in honeycomb–foam sandwich beams

In engineering applications where the use of lightweight structures is important, the introduction of a viscoelastic core layer, which has high inherent damping, between two face sheets, can produce a sandwich structure with high damping. Sandwich structures have the additional advantage that their strength to weight ratios are generally superior to those of solid metals. So, sandwich structures are being used increasingly in transportation vehicles. Knowledge of the passive damping of sandwich structures and attempts to improve their damping at the design stage thus are important. Some theoretical models for passive damping in composite sandwich structures are reviewed in this paper. The effects of the thickness of the core and face sheets, and delamination on damping are analyzed. Measurements on honeycomb–foam sandwich beams with different configurations and thicknesses have been performed and the results compared with the theoretical predictions.