Geometrically nonlinear analysis of sandwich structures

In this work a finite element model is extended for geometrically nonlinear analysis of sandwich plate-shell structures, to study the nonlinear static response of sandwich plates or curved shells which can have a hard or soft core sandwiched between stiff elastic layers. The finite element is obtained by assembling all element-layers through the thickness using specific assumptions on the displacement continuity at the interfaces between layers, but allowing for different behavior of the layers. The stiff elastic layers are modeled using the classic plate theory and the core is modeled using the Reddy's third order shear deformation theory. Using the Newton-Raphson incremental-iterative method, the equilibrium path is obtained, and in case of snap-through occurrence the automatic arc-length method is used to track the full load displacement distribution. This simple and fast element model is a non-conforming triangular flat plate/shell element with 24 degrees of freedom for the generalized displacements. It is benchmarked in the solution of some illustrative plate-shell examples and the results are presented and discussed with numerical and experimental alternative models. (C) 2016 Elsevier Ltd. All rights reserved.