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

Two finite strip methods, namely the full-energy and the semi-energy FSM, are developed for predicting the geometrically non-linear response of channel sections with simply supported ends when subjected to uniform end shortening in their plane. The developed finite strip methods are then applied to analyze the post-local-buckling behaviour of some representative channel sections. The comparison of results revealed the fact that for the channel sections under study, the full-energy finite strip method is capable of predicting results with a greater degree of accuracy than that of the results obtained by the semi-energy finite strip method. This is due to the fact that a lower level of compressional stiffness is experienced in the case of the full-energy FSM results as compared to those observed in the case of semi-energy FSM. It is however worth noting that at the expense of slightly less accurate results, the current semi-energy analysis is benefiting from considerably less computer CPU time, due to the implementation of a fairly small number of degrees of freedom, as compared to the CPU time elapsed by the computer when the full-energy method is applied. It is noted that in the current semi-energy approach only one term is utilized, whereas several terms are implemented in the formulation of the full-energy method. Therefore, it is expected that the accuracy of the semi-energy approach will improve and correspondingly the required computer CPU time will increase if more than one term is utilized in its formulation.