Experimental Investigations on the Folding Process of Polyurethane Foam-Filled Aluminium Columns with Circular Discontinuities

Abstract

This article performs an experimental study on empty and polyurethane foam-filled thin-walled aluminium columns with quadrangular cross section in two different conditions: with or without centrally circular discontinuities on the longitudinal or latitudinal sides of column cross section during the folding process (local buckling). In each sample, two circular cut-outs were perforated into the opposite sides of specimens and the samples were axially compressed between two rigid platens under the quasi-static loading. The samples were prepared with different initial lengths, filling conditions and cut-out diameters. Effects of mentioned characteristics are investigated on total absorbed energy, specific absorbed energy, crush force efficiency, peak load and folding wavelength. Experimental observations show that by increasing the cut-out diameter and also by filling the column with the foam, folding wavelength decreases. Also, experiments show that there is an optimum diameter for the longitudinal side cut-outs which total absorbed energy by the filled rectangular specimen with the optimum cut-out is the highest. Furthermore, results illustrate that total absorbed energy increases due to increment of column length, but specific absorbed energy and crush force efficiency are independent of column length.