Theoretical and experimental study on the flattening deformation of the rectangular brazen and aluminum columns

This paper presents a theoretical and experimental study on lateral compression of square and rectangular metal columns. Some theoretical relations are derived to predict the absorbed energy, the specific absorbed energy and the instantaneous lateral load during the lateral compression. Analytical relations are obtained in two stages: elastic and plastic parts. In the plastic zone, the total absorbed energy by the column is calculated, based on the energy method. Then, an analytical equation is derived to predict the instantaneous lateral load. In the elastic part, the instantaneous load is obtained by linear behavior assumption. To verify the theoretical formulas, some lateral compression tests were carried out on square and rectangular columns and the experimental results are compared with the theoretical predictions, which shows a good agreement. Also, based on the experiments, effects of geometrical dimensions and material properties of the columns on the energy absorption capability are investigated. The results show that the absorbed energy by a column increases proportional to the column length. Also, columns with the thicker wall have the higher specific absorbed energy and so, rectangular columns with the thicker wall are the better energy absorbers during the flattening process. Also, the absorbed energy increases when the length of the column edge along which the load is applied decreases. Also, it is found that the specific absorbed energy by the aluminum columns is higher than the brazen ones and therefore, flattened columns with the high ratio of the flow stress/density are the better energy absorbers.