A geometrically nonlinear analysis through hierarchical one-dimensional modelling of sandwich beam structures

In this work, a layerwise beam model based on Carrera's Unified Formulation (CUF) is developed to solve the geometrically nonlinear problem of sandwich beams with a special emphasis on global-local buckling interaction. In the framework of CUF, the order of a beam theory can be chosen freely to ensure the desired accuracy and computational effort. For beam theories with different orders, the element stiffness matrix can be derived in a compact form. The efficient and robust Asymptotic Numerical Method (ANM) is used as the nonlinear solver. A comparison with classical two-dimensional finite element analysis shows that the proposed models can provide accurate predictions. The global and local buckling problems are also addressed. It is found that accurate results can be obtained through the proposed CUF-based beam model with reduced computational costs.