Quasi-static axial crushing performance of thin-walled tubes with circular hole discontinuities

Abstract

This paper investigates the crashworthiness performance of square pipes with induced holes. Glass reinforced epoxy (GFRP) specimens were fabricated and tested under quasi-static axial crashing. Four design parameters were chosen, each at three levels, to calculate crashworthiness indicators. The design parameters are the hole diameter (d), the hole position to specimen length ratio (P/L), the number of holes and distribution (n), and crosshead speed (V). Taguchi technique has been adapted to get the optimum crashworthiness parameters. Experiments based on Taguchi’s orthogonal array with 9 experimental runs (L9) were performed. Optimal conditions with the maximum absorbed energy (U) and minimum initial peak force ( ${\mathrm{F}}_{\mathrm{i}\mathrm{p}}$ ) were determined. The main effects, signal to noise ratio (S/N), and analysis of variance (ANOVA) have been investigated. Results indicated that “V” followed by “d” are the highest influencing parameters on the values of “U” with a contribution of 49% and 43%, respectively. The dominant influencing parameter on the values of ${\mathrm{F}}_{\mathrm{i}\mathrm{p}}$ is “n” with a contribution of 94%. Finally, confirmation tests were carried out to validate the estimated model with respect to experimental results. The optimum U and ${\mathrm{F}}_{\mathrm{i}\mathrm{p}}$ of GFRP square pipes with circular cutouts were compared with those of non-porous specimens.