An improved model for the prediction of intra-cell buckling in CFRP sandwich panels under in-plane compressive loading

O.T. Thomsen, W.M. Banks

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Local instability in the form of "intra-cell buckling" or "dimpling" is a well-known failure mode in honeycomb-cored sandwich panels with very thin faces. Most work reported on the subject suggests relatively simple design formulae for the estimation of the intra-cell buckling load. It is however widely known that these classical design formulae in some cases considerably underpredict the intra-cell buckling load. In this paper a series of experimental results obtained for different CFRP/honeycomb sandwich panel configurations loaded in compression are presented. The results confirm that the "classical" design formulae provide overly conservative results. During the tests the intra-cell buckling patterns were monitored carefully, and it was observed that the hitherto assumed buckling patterns did not correspond to the experimental observations. Based on these findings a new simplified design formula is suggested, which for the investigated CFRP/honeycomb sandwich panels provides significantly more accurate predictions than the "classical" design formulae.
Original languageEnglish
Pages (from-to)259-268
Number of pages9
JournalComposite Structures
Issue number3-4
Publication statusPublished - 1 Dec 2003


  • CFRP sandwich panels
  • in-plane compression loading
  • intra-cell buckling
  • Dimpling
  • experimental investigation
  • improved theoretical model

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