Compressive and shear responses of shaped-sheet pyramidal truss core for reinforced sandwich structure

Construction of sandwich materials involves a composite material structure of light weight, high strength and good dynamic properties. In recent days, demands for materials with high strength and light weight are ever increasing. In line with these trends, research about sandwich materials has been actively conducted in diverse industrial sectors. In this study, a sandwich structure named as "shaped-sheet pyramidal truss core" is proposed to improve the mechanical strength, at the same time resulting in manufacturing process suitable for massive production by changing the cross-sectional shape at the central portion of the core. The out-of-plane compressive and shear responses of the shaped-sheet pyramidal truss core were measured for two relative densities ( 0.02 ≤ ρ ≤0.05 ) and were compared with the finite element (FE) predictions. In the FE results both compression and shear test, it shows that the core with low relative density has superior behaviours before first buckling. The compressive experiments over-estimate the strength due to work hardening of the material and bonding effects. The experimental results at large deformation, however, decrease due to debonding or slip between bonding areas. Additionally, the influence of the debonding effect is larger under shear test.