Transverse Shear Stiffness of Composite Honeycomb Cores and Efficiency of Material

Abstract

Effective transverse shear moduli of composite honeycomb cores are important material properties in analysis and design of sandwich structures. An analytical approach using a two-scale homogenization technique is presented to predict the effective transverse shear stiffnesses of thin-walled composite honeycomb cores with general configurations. To improve the performance of core transverse shear behavior, a nondimensional index, the so-called efficiency of material (EOM), is introduced to evaluate the optimal design of periodic cellular cores. Explicit formulas of effective transverse shear stiffnesses and the corresponding efficiencies of material are provided for three typical honeycomb cores consisting of reinforced sinusoidal, elliptical, and reinforced hexagonal geometries. It has been shown that the efficiency of material is only determined by nondimensional core geometric ratios. The effects of these ratios on the EOM of effective transverse shear stiffnesses, which are examined in detail in this study, offer insight and guidelines for optimal design and selection of honeycomb cores. The explicit formulas for the effective transverse shear stiffness properties of thin-walled composite honeycomb cores and their related EOMs can be used effectively to predict and optimize the core transverse shear behavior in sandwich structures.