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

• Published in: Composite structures Vol. 65; no. 3; pp. 259 - 268
• Main Authors: Thomsen, Ole Thybo, Banks, William M.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2004
• Subjects: CFRP sandwich panels; Dimpling; Experimental investigation; Improved theoretical model; In-plane compression loading; Intra-cell buckling; Improved theoretical model; In-plane compression loading; Intra-cell buckling; CFRP sandwich panels; Dimpling; Experimental investigation
• ISSN: 0263-8223
• DOI: 10.1016/j.compstruct.2003.11.002

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.