Post-Local-Buckling Behavior of Continuous Beams

A numerical method is presented for predicting the post-buckling response of thin-walled continuous beams. The proposed method includes a numerical integration procedure in conjunction with the flexibility matrix method of analysis. Nonlinearities due to local buckling and nonlinear material characteristics are accounted for by the nonlinear moment-curvature relations derived with the aid of the effective width concept. Using the moment distribution of an elastic prismatic beam based on the nonbuckling analysis, with an appropriate selection of the correction factor, the numerical iterative procedure converges rapidly. Typical beam sections and loading and support conditions are investigated. The difference between the computed moment distribution and that of an elastic prismatic beam is not appreciable for symmetrical sections with ordinary loading conditions. Simplified design methods with acceptable accuracy for predicting deflections in the post-buckling domain are developed.