An efficient approach for post-buckling analysis of sandwich structures with elastic-plastic material behavior

This paper aims to propose an efficient and accurate framework for the post-buckling analysis of sandwich structures with elastic-plastic material behaviors. Correspondingly, efforts are made in two aspects, i.e., the model and the nonlinear solver. A new one-dimensional sandwich model is firstly established, in which the skins are described by Euler-Bernoulli beam theory, while the core layer is approximated by high-order functions. The Ramberg-Osgood elastic-plastic material behavior is considered for the core and the linear elastic for the skins. Green-Lagrange strains are used for accurately describing large deformations in both skins and core layer. The resulting nonlinear equations are then solved by an efficient and robust path-following technique, i.e., the Asymptotic Numerical Method (ANM), in which the bifurcation indicator is introduced to precisely detect bifurcation points and the corresponding instability patterns. Several typical instability phenomena (global buckling, local-global-coupling instability and shear crimping) are investigated and numerical results demonstrate that the proposed approach is able to accurately characterize the post-buckling behaviors of sandwich structures with few computational cost. (C) 2019 Elsevier Ltd. All rights reserved.