Nonlinear finite element modelling of degradation and failure in folded core composite sandwich structures

Abstract

The presented research investigates the numerical modelling of sandwich structures with aramid paper foldcore and fibre composite face sheets in quasi-static and dynamic load cases. For that purpose, existing approaches reproducing cellular sandwich structures on the basis of shell-based meso-models are adapted to aramid paper foldcores and further developed. In order to consider the aramid papers inhomogeneous nature in the thickness direction a new modelling approach with layered shell elements is proposed. A methodology to derive the material properties of the individual layers from global paper properties measured experimentally is presented. In combination with continuum damage mechanics and a cohesive interface for the modelling of the carbon composite surface skin the proposed modelling approach is used to reproduce drop tower and gas gun impact test. By comparison of the experimental and numerical results the strengths and weaknesses of the presented modelling approach are discussed and evaluated.