PREBUCKLING AND POSTBUCKLING RESPONSE OF CURVED, THIN, COMPOSITE PANELS WITH CUTOUTS UNDER COMPRESSION

Analytical predictions of the postbuckling response of curved composit e panels are difficult, especially under in-plane compression, because of the presence of snap-back with a steep negative slope beyond the b ifurcation point. In this study, the pre- and postbuckling response of curved laminated panels with cutouts is investigated by developing a new finite element based on the free formulation. This triangular, fla t, shell element, in conjunction with the updated Lagrangian form of t he co-rotational approach, accounts for the coupling terms arising fro m general material anisotropy, as well as large displacements and rota tions. The analysis predictions correlate well with the corresponding experimental data available in the literature. Review of the studies i n this subject area reveal that none of the available methods, includi ng the STAGS-C1 finite element program, is capable of providing the fu ll description of the postbuckling phenomenon beyond bifurcation for c urved composite panels with small cutouts.