Equivalent transverse shear stiffness of honeycomb cores

Abstract

This work deals with the influence of geometry on the equivalent transverse shear stiffness of honeycomb sandwich plates. First, it presents the analytical solution for a two-dimensional basic cell of honeycomb structures by the two scale method of homogenization for periodic media. This solution gives the first order equivalent transverse shear modulus of honeycomb structures. Then the equivalent transverse shear stiffness of a regular honeycomb core is evaluated by the unite element method using a three-dimensional basic cell and the analytical solution for honeycomb structures. The equivalent transverse shear stiffness of a honeycomb core, in general, depends on the geometry of the sandwich plate. However, when the core depth is large compared to the hexagonal size, the aspect ratio of face panel thickness to hexagon wall thickness has little influence, and the transverse shear stiffness approaches the solution of honeycomb cellular structures. Based on the numerical study, an improved lower limit for the equivalent transverse shear stiffness of honeycomb cores is proposed, and an improved local shear stress of honeycombs is presented.