Numerical analysis of face sheet buckling for a CFRP/Nomex honeycomb sandwich panel subjected to bending loading

The objective of this study is to establish a bending strength prediction method for a thin CFRP face sheet/ Nomex honeycomb sandwich panel, for which the failure mode is face-sheet/core debonding derived from local buckling of the face sheet. Stress and buckling eigenvalue analyses were conducted using a detailed core model reproducing honeycomb structure and a solid core model in which the core was homogenized as solid elements. In both the detailed model and the solid core model, the buckling load calculated using the buckling eigenvalue analysis agreed well with the experimentally obtained failure loads. Results also showed that the face sheet buckling waveform was not intra-cell buckling but global buckling. The computational time was reduced to less than one-half using the homogenized honeycomb core (solid elements). The results imply that the homogenized solid core model is suitable for estimating the bending strength of the CFRP/Nomex honeycomb sandwich panel.