Response of elliptical composite cylinders to axial compression loading

The results from semianalytical predictions and experiments are used to stu dy the response of composite cylinders with elliptical cross sections loade d axially to a significant percentage of their buckling load. The semianaly tical approach is based on the methods of Marguerre, Rayleigh-Ritz, and Kan torovich. The radius of curvature and the displacements are approximated by expansions in harmonic series in the circumferential are-length coordinate , and the coefficients of the displacement series are unknown functions of x which are solved for using the finite-difference method. The primary feat ures of the predicted response are first described. Then the experiments ar e described and results for elliptical cylinders with varying degrees of or thotropy are compared with predictions. Where appropriate, calculations bas ed on the analysis of circular cylinders are compared with the semianalytic al calculations for the ellipse. Correlation between experiments and predic tions is good, and it is demonstrated that despite the noncircular cross se ction, many responses of an ellipse are very similar to the axisymmetric re sponse of circular cylinders subjected to an axial load. The similarity is independent of the degree of orthotropy of the elliptical cylinder.