Refined Analysis of Torsion and In-plane Shear of Honeycomb Sandwich Structures

Abstract

Multiple-Pass Homogenization (MPH) technique is used to derive formulas for equivalent torsional and in-plane shear stiffness properties of sandwich plates with periodic core structures. In the first pass of the MPH, a discrete core structure is homogenized in a principal axis resulting in piecewise constant material properties, based on which the second pass can be analytically processed with respect to macroscopic torsion and in-plane shear modes. Two equivalent shear stiffness properties of periodic core structures, G*cxyand G*cxy, corresponding to torsion and in-plane shear, respectively, are conceptually and analytically distinguished from each other. By using the Saint-Venant’s semi-inverse method and periodic boundary conditions, analytical solutions of the equivalent shear stiffness are explicitly obtained in the form of Fourier series, which consist of a Voigt-type upper bound term and a correction term. Effects of thickness ratio and core transverse shear stiffness on the two equivalent shear stiffness properties are assessed and discussed. The approximation scheme proposed by this study improves modeling of sandwich structures as orthotropic plates, which is expected to be useful in the practical design and optimization of sandwich structures.