Single and multi-layer core designs for Pseudo-Ductile failure in honeycomb sandwich structures

This paper investigates the possibility of triggering ductile modes of failure in a high-performance sandwich structure by employing a multi-core design with dispersed composite plies. Here, two sandwich configurations, based on a carbon fiber reinforced epoxy face sheet and a NomexTM honeycomb core, have been manufactured and their properties evaluated in flexure and compression. The mechanical performance of these multi-layer configurations was then compared with the properties offered by a conventional sandwich panel of similar thickness, manufactured using the same number of carbon/epoxy prepreg plies. The effect of span length on the flexural and compressive properties of the sandwich panels was investigated by performing tests on differently-sized specimens. Theoretical models have been developed to predict the mechanical properties of the sandwich panels. In both theoretical and experimental approaches, superior mechanical properties were obtained in the shorter span length samples. The deviation between the predicted and experimental results was reasonably low.