Experimental and theoretical study of the lateral compression process on the empty and foam-filled hexagonal columns

• This article investigates the flattening process on the hexagonal metal columns.
• Analysis is performed on empty and filled columns theoretically and experimentally.
• Instantaneous and mean lateral load of hexagonal columns is derived, theoretically.
• Effects of foam-filler and geometrical characteristics on lateral load are studied.
• Comparison of theoretical and experimental results shows a good correlation.

In this article, a new analytical model of plastic deformation during the flattening process on hexagonal metal columns under the lateral loading in the quasi-static condition is presented. Based on the introduced model, some theoretical relations are derived to forecast the average and instantaneous lateral load of the hexagonal column in two different conditions: empty and polyurethane foam-filled. Then, some lateral compression tests were carried out on the empty and foam-filled metal columns and the experimental results were compared with the theoretical predictions by the present formulas that showed an admissible correlation. The theoretical relations estimate variations of the lateral load in terms of lateral displacement. The theoretical analysis shows that the lateral load on the hexagonal column during the flattening process is dependent on the column wall thickness, column length, and material properties of the column and polyurethane foam-filler. Finally, the effects of geometrical characteristics of the hexagonal columns and material properties of the columns and foams on the lateral load are investigated, experimentally.