Strain localization in circular honeycombs under in-plane biaxial quasi-static and low-velocity impact loading

Strain localization in a finite block of circular honeycomb is studied using a phenomenological approach based on the structural response of the honeycombs. The deformation modes characteristic for a circular honeycomb material under in-plane biaxial compression are identified from the experiments and described analytically for compression strains up to about 15%. It is concluded that the particular deformation modes depend on the local strain field, and modes with different dominant strains can co-exist inside a finite block subjected to equi-biaxial remote strains. The relationships between the local strain components for the development of these modes are determined. Using the proposed approach to the strain localization, it is shown that for equal remote strains applied to a finite block of honeycombs, larger remote stresses would occur when assuming homogeneous deformation inside the block in comparison to the calculated stress when the strain inhomogeneity takes place. A comparison between the theoretical and experimental results is made for a finite honeycomb block under quasi-static equi-biaxial compression.