A nonlinear multiscale finite element model for comb-like sandwich panels

Composite materials and lightweight construction parts are increasingly replacing classic materials in practical engineering applications. However, it is often difficult to simulate their mechanical behavior due to their complex structure, where a full FEM discretization would lead to immense calculation times and memory requirements. While homogenization methods are established to determine effective properties of composite microstructures, most of these approaches are unable to accurately reflect nonlinear system behavior. In this work a coupled multiscale approach is presented specifically for sandwich panels with comb-like core structures. A numerical homogenization is carried out in each iteration and load step of a nonlinear simulation, allowing to describe local effects of nonlinearity such as face sheet buckling or plastic flow. Several numerical simulations using different core geometries are carried out. The numerical results agree very well to full scale reference solutions, while drastically reducing the size of the equation system. Moreover, the method is well suited for parallelization and runs effectively on modern hardware topologies.