Abstract
Thin spruce veneer was corrugated to make wooden honeycomb elements for the lightweight core of sandwich panels. Wood honeycomb core (VHC) is a honeycomb element in which the fiber direction of the veneer is aligned in the thickness direction of the panel. Corrugated veneer core (CVC) is similar to corrugated cardboard, in which the fiber direction of the veneer is aligned in the direction of the wave. The cores were put between two sheets of plywoods to make sandwich panels and their compressive strength (σc) and compressive Young's modulus (Ec) in the thickness direction were measured. The density (ρc) of VHC and CVC varied from 10 to 130kg/m3. The specific strength (σc/ρc) of VHC was 7 to 20 times greater than that of paper honeycomb. The ρc and Ec of CVC were almost the same as those of paper honeycomb while its rupture energy was about 3 times greater than that of paper honeycomb. Finer wave resulted in greater ρc and σc of CVC, and greater σc/ρc was achieved by smaller curvature with thicker veneer. Plural veneers could be glued during corrugation, but such a plied-CVC showed smaller σc/ρc than mono-layered CVC probably because of failure in gluing.
