Modeling of tapered sandwich panels using a high-order sandwich theory formulation

Abstract

A newly developed high-order sandwich theory formulation is presented, which enables the analysis of sandwich beams or plates with variable core thickness. The faces are assumed to be of constant thickness and may be inclined arbitrary angles α 1 and α 2 , respectively, relative to the sandwich panel reference plane. The core thickness may change linearly over the length of the sandwich panel. The core is modeled as a specially orthotropic solid possessing stiffness in the out-of-plane direction only, thus including the transverse core flexibility in the modeling. The faces are modeled as laminated beams or plates including bending-stretching coupling and transverse shear effects. To validate the proposed high-order theory, the numerical results are compared with results obtained from finite element analysis, and a close match is observed. Furthermore, to demonstrate the features of the developed high-order sandwich theory formulation, numerical results obtained for two different types of tapered sandwich beams in three-point bending are presented. The characteristics of the elastic responses of the two sandwich panel configurations are compared with special emphasis on the complicated interaction between the faces through the core material. The analyses show that severe localized bending effects are displayed in the vicinity of load introduction and support points and in the vicinity of points/locations of abrupt geometric changes. These localized bending effects induce severe stress concentrations and may severely endanger the structural integrity of the sandwich panels under consideration.