Quasi-static indentation responses of FMLs/2.5D woven carbon-fiber honeycomb sandwich structures under different structural parameters.

• 2.5D woven carbon-fiber honeycomb sandwich structures was manufactured and investigated both experimentally and numerically. • Effects of varied parameters of the sandwich structure on the mechanical, especially the energy absorption characteristic were investigated through quasi-static indentation experiments. • The panel strength and honeycomb core strength were found synergistically determine the failure mode of the sandwich structure. Here, a new type of sandwich structure made of fiber metal laminates (FMLs) as facesheet and 2.5D woven carbon-fiber (CFRP) honeycomb as core was developed. The FMLs/CFRP honeycomb sandwich structures were subjected to quasi-static indentation tests to investigate the mechanical response with the variation of panel structure, honeycomb cell element size, honeycomb core wall thickness, and honeycomb core height. In addition to experiments, a finite element method (FEM) model was also created in ABAQUS/Explicit to analyze the damage mechanisms and failure modes of honeycomb sandwich structures under quasi-static indentation. Both the experimental and FEM simulation results revealed that the honeycomb sandwich structure underwent two different failure modes under quasi-static loading: localized damage dominated by indentation and global damage due to overall bending deformation. The combination of panel strength and honeycomb core strength determined the failure mode of the sandwich structure. Damage analysis of the honeycomb core showed that it mainly underwent fiber compression damage and matrix compression damage under quasi-static indentation. This study provides guidance to optimize the design of honeycomb sandwich structures. [ABSTRACT FROM AUTHOR]