Z. Gurdal et B. Grall, BUCKLING ANALYSIS OF GEODESICALLY STIFFENED COMPOSITE PANELS WITH DISCRETE STIFFENERS, Journal of aircraft, 31(5), 1994, pp. 1197-1204
A computationally efficient analysis is developed to predict the buckl
ing loads of geodesically stiffened composite panels with discrete pla
te-like stiffeners under in-plane loads. The procedure accounts for th
e contribution of the in-plane extensional and out-of-plane bending st
iffnesses of the stiffeners through the use of a Lagrange multipliers
technique in an energy method solution. The analysis is capable of pre
dicting the buckling loads of grid-stiffened panels for a variety of s
tiffener aspect ratios and stiffener laminate stacking sequences. It c
an also be used to design panels with variable density grid stiffeners
across the panel width. Results of the proposed analysis showed that
the buckling loads of geodesically stiffened panels are predicted more
accurately, especially in the case of panels with shallow stiffeners,
compared to an earlier analysis that assumes the stiffeners to be bea
m-like components. For plate-like stiffeners, laminate stacking sequen
ce of the stiffeners is found to have a substantial effect on the crit
ical load of a panel. It was demonstrated that the optimal stiffener i
s not always unidirectional, and tailoring the stiffener ply sequence
can lead to improvement in panel stability. It was also shown that pan
els with a variable grid density can lead to designs with improved buc
kling performance compared to uniform density panels.