Bending collapse of thin-walled rectangular section columns

This paper reviews the existing methods of collapse analysis for thin-walled rectangular section tubes subjected to bending about a principal axis and suggests a new collapse mechanism that gives an improved analytical solution for the moment–rotation relationship. The new model is kinematically admissible and completely analytical. It involves two unknown constants, half the length of the folding wave and the rolling radius in the calculation, which are determined by minimising a mean crumpling moment. The new analytical solution shows good agreement with experimental results.