| In this study, the mechanism of peel fracture in honeycomb-core sandwich panels was investigated, and the role of resin fillets on energy absorption was elucidated. Fillet deformation and fracture were shown to control the delamination resistance of sandwich panels (GCCD), to a great extent. The GCCD data for variety of panels, made with various materials were normalized by the delamination energy of the skin material (GC). The data collapsed to a single curve when GCCD/GIC was plotted against the residual area fraction of the resin remaining on the core side after the peel (FARR). This trend was confirmed with finite element models developed. A detailed stick slip mechanism for crack advance was proposed, and its existence was supported by the load traces, FE models and fractography.; In addition, the effect of various factors on GCCD was investigated including void formation, temperature, contamination and facesheet thickness. Increase in void formation and reduction in facesheet thickness negatively affected the results. The FE models were able to predict the results of theses experiments reasonably well. |
