Response of Elliptical Composite Cylinders to Axial Compression Loading

Abstract

The results from semianalytical predictions and experiments are used to study the response of composite cylinders with elliptical cross sections loaded axially to a significant percentage of their buckling load. The semianalytical approach is based on the methods of Marguerre, Rayleigh-Ritz, and Kantorovich. The radius of curvature and the displacements are approximated by expansions in harmonic series in the circumferential arc-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 features of the predicted response are first described. Then the experiments are described and results for elliptical cylinders with varying degrees of orthotropy are compared with predictions. Where appropriate, calculations based on the analysis of circular cylinders are compared with the semianalytical calculations for the ellipse. Correlation between experiments and predictions is good, and it is demonstrated that despite the noncircular cross section, many responses of an ellipse are very similar to the axisymmetric response of circular cylinders subjected to an axial load. The similarity is independent of the degree of orthotropy of the elliptical cylinder.