Analyses and preliminary tests of a balsa sandwich core with improved shear properties

End grain balsa is a common core material in sandwich structures. The main properties of interest of a sandwich core, in particular for marine applications, are the shear stiffness and shear strength. The end grain arrangement does not fully utilize the anisotropy of balsa wood for the benefit of shear properties. A new arrangement of balsa blocks in a sandwich core was developed and numerically analyzed. This new core, which consisted of an assembly of oddly shaped balsa blocks, allowed the grains in various balsa blocks to be oriented for example at 45° to the normal of the core. The effective out-of-plane shear stiffness was isotropic. Numerical analyses predicted a superior shear stiffness, which was confirmed by preliminary tests.