Finite element forming simulation of complex composite sandwich panels

The sandwich composite forming process is an affordable high-volume technology developed to manufacture 3D composite sandwich panels with complex curvatures and varying thickness from a flat format by forming with a set of matched tools. Finite element models were developed as numerical tools to facilitate the process design and optimisation, and to extend the opportunity for wider industry uptake. The core was modelled at different scales: Meso-scale model was employed to investigate forming mechanism, while macro-scale model was used to replicate overall forming response. Results from meso-scale simulation indicate that the formability for complex curvature is mainly derived from the bending deformation of the sandwich panel, while the through-thickness core crushing provides the formability for variable thickness. A macro-scale model was developed to predict the homogenised forming behaviour of the core based on Abaqus/Explicit. Results indicate that this macro-scale model is able to significantly reduce the computational time and effectively inform the formability, enabling process optimisation. The numerical tool was employed to design the forming process for a generic demonstrator component. The manufacturing solution determined by simulation shows a good agreement with experiment, indicating the suitability of the developed model for industry applications.