Enhanced vibration and damping characteristics of novel corrugated sandwich panels with polyurea-metal laminate face sheets

All-metallic sandwich panels with lattice truss cores are typically ultralight, stiff and strong, yet poor in passive vibration damping. Novel laser-welded corrugated-core (LASCOR) sandwich panels with polyurea-metal laminates (PML) as face sheets were proposed and fabricated, and their vibration and damping characteristics were systematically investigated, both experimentally and numerically. Frequency/time response curves, natural frequencies, vibration mode shapes and damping loss factors were measured and compared with LASCOR sandwich panels without embedded polyurea layers. A combined finite element-modal strain energy (FE-MSE) method was proposed to predict the vibration damping performance and explore the underlying enhancement mechanisms, with the frequency-dependent damping behaviors of polyurea considered. Good agreement was achieved between numerical simulations and experimental measurements. The PML face sheets enabled remarkable damping enhancement, due mainly to viscoelastic energy dissipation of the polyurea layers. The capacity of the sandwich panel in passive vibration suppression could be further improved by tailoring the polyurea layer thickness and the distribution of polyurea layers.