Geometric non-linear analysis of box sections under end shortening using three different versions of the finite-strip method

Three finite-strip methods, (FSM) namely the semi-energy, full-energy semi-analytical and the full-energy spline FSM, are developed for predicting the geometrically non-linear response of box sections with simply supported ends when subjected to uniform end shortening in their plane. The developed FSMs are then applied to analyze the post-local-buckling behavior of some representative box sections. Although, in general, a very good agreement is observed to exist among the results obtained by all the different methods, it is revealed that in the advanced stages of post-buckling, the semi-energy method predicts results which are slightly less accurate than those obtained by the full-energy methods. This is due to the fact that a slightly higher level of compressional stiffness is experienced in the case of the results obtained by the semi-energy approach as compared to those observed in the cases of the results obtained by the full-energy methods. It is however worth noting that the current semi-energy analysis is based on a single term approach. Thus, it is expected that the accuracy of the semi-energy approach will improve and correspondingly the number of degrees of freedom involved will increase if more than one term is utilized in its formulation. (C) 2006 Elsevier Ltd. All rights reserved.