Flattening process on folded quadrangular columns under the lateral loading- a novel energy absorption method

This article introduces a novel method to improve energy absorption performance of thin-walled columns with square and rectangular cross-sections subjected to distributed quasi-static lateral compression loading during different lateral flattening processes. Firstly, some square and rectangular columns made of aluminum and brass alloys are compressed in the axial direction to transform them into folded columns. Then, the folded specimens are used in four different lateral energy absorption processes as initial samples. All the lateral flattening tests are carried out between rigid platens. All the used specimens in the four flattening processes are prepared by initial simple square and rectangular columns. In one flattening process, the simple quadrangular specimens are used. In the second process as a novel flattening process, the folded samples are tested. Furthermore, in two other processes, the initial specimens of the novel flattening processes are prepared by folding and cutting the simple quadrangular specimens. Effects of different parameters consist of material type, wall thickness, cross-sectional aspect ratio, and length of the specimens and also, flattening process type and lateral loading direction are discussed on energy absorption performance of the quadrangular specimens. Totally, the performed experiments show that the new lateral energy absorption processes increase specific absorbed energy by the quadrangular specimens up to 7 times; and enhance their total absorbed energy more than 13 times of the corresponding simple specimens.