A novel computational framework for exact stress analysis and bending behavior of sandwich panels with non-homogeneous cores

Abstract

A novel computational framework is proposed for accurate stress analysis of sandwich panels with any non-homogeneous cores based on the quadrature element method (QEM). To solve the problem of inaccurate assumption of through-thickness shear strain distribution for the non-homogeneous core, existing in engineering theories, the core is modeled by a quadrature plate element. Due to the non-homogeneity of the core, however, its stiffness matrix cannot be accurately obtained by the nodal quadrature which is widely used in QEM. Therefore, an explicit formulation for an arbitrary number of nodes and nodes of any type is worked out to get an accurate stiffness matrix. Numerical solutions of sandwich panels with different cores subjected to various loads are presented. Results are verified by the conventional finite element method and existing analytical solution. It is found that the deformation and all stress components can be accurately predicted by the present method with a small number of nodes and thus the method is efficient in analyzing any type of sandwich panels under general loads and boundary conditions. The influence of power-law index and loading type on the deflection, through-thickness distributions of stresses and shear strain as well as the location of the neutral surface is analyzed. An important outcome of this investigation is that the existence and location of the neutral surface of a sandwich panel with a soft core are highly dependent on the loading conditions, which should be remarkedly noted in sandwich theories and engineering design.