Computationally Efficient Concurrent Multiscale Framework for the Nonlinear Analysis of Composite Structures

This paper presents a computationally efficient concurrent multiscale platform to undertake the nonlinear analysis of composite structures. The framework exploits refined 1D models developed within the scheme of the Carrera Unified Formulation (CUF), a generalized hierarchical formulation that generates refined structural theories via a variable kinematic description. CUF operates at the macro and microscale, and the macroscale interfaces with a nonlinear micromechanical toolbox. The computational efficiency derives from the ability of the CUF to obtain accurate 3D-like stress fields with a reduced computational cost. The nonlinearity is at the matrix level within the microscale, and its effect scales up to the macroscale through homogenization. The macro tangent matrix adopts a perturbation-based method to have meliorated performances. The numerical results demonstrate that the framework requires some $50 % $ of the computational time and $10 % $ of memory usage of traditional 3D finite elements (FE). Very detailed local effects at the microscale are detectable, and there are no restrictions concerning the complexity of the geometry. The present paper is a companion of a linked work dealing with linear material implementations.