A Study on Crushing Behavior and Energy Absorption Capacity of a Thin-walled Rectangular Tube under Axial Compression

The crushing behaviour of a mild steel thin-walled rectangular tube under axial compression is investigated. The crushing process with only the compact mode is considered. The characteristic values of the crush load of a rectangular tube with an arbitrary aspect ratio of cross section are empirically obtained. In the empirical results, two different peak-values per period in the crush load-distance curve are considered where the peak values are obtained from an ideal model. The ideal model, recently proposed by the authors, is primarily based on accounting the ratio of outward length to half-wave fold length in the crushing process. The crush distance after the first perfect fold is formed and the general crush distance per fold are theoretically derived using the geometrical configuration of a crushing fold. The theoretical and empirical results are shown to agree. The crush load-distance curve is assumed to be the sum of a fourth power term and two cosine functions. The energy absorption capacity is the integral of this curve over the allowed crush distance. The number of crush folds is then easily calculated.