Crashworthiness analysis of multi-cell prismatic structures Annisa Jusuf, Tatacipta Dirgantara * , Leonardo Gunawan, Ichsan Setya Putra Lightweight Structures Research Group, Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia article info Article history: Received 15 April 2014 Received in revised form 5 November 2014 Accepted 10 November 2014 Available online 27 November 2014 Keywords: Thin-walled column Single-walled Double-walled Multi-cell Impact Dynamic axial crushing abstract This paper presents a numerical and experimental study of several configurations of multi-cell columns compared to single-walled and double-walled columns subjected to dynamic axial impact forces. The impact of the columns was numerically analysed using FEM and also verified by experimental testing. The effect of the column mass and thickness of the multi-cell columns compared to single- and double- walled columns was also studied. The results showed that, by analysing a group of columns with the same thickness and weight, the energy absorption efficiency can be significantly improved by intro- ducing internal ribs to the double-walled columns. The results showed that the crushing force of the middle ribs (MR) multi-cell columns was the highest, followed by the corner ribs (CR) multi-cell col- umns, the double-walled (DW) columns and the single-walled (SW) columns, respectively. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction The axial crushing resistance characteristic of single-cell thin- walled columns has long been the subject of extensive research, since single thin-walled prismatic columns were identified as a very efficient impact energy absorption system within the space- frame concept of cars [1, 2], train structures [3, 4] and helicopter subfloors [5, 6]. Usually, the focus of investigation is on increasing the energy absorption performance of a column by varying the cross-sections, such as square, circular, octagonal, hexagonal, top hat and double hat. Apart from the single-cell concept, the multi-cell column has also been considered as an alternative solution to increase the energy absorption performance. Chen and Wierzbicki [7] presented theoretical solutions to calculate the mean crushing force of single- cell, double-cell and triple-cell columns, as can be seen in Fig. 1(a). The results showed that the energy absorption efficiency of double- cell and triple-cell columns is higher than that of single-cell col- umns. Furthermore, Kim [8] carried out an optimization process of a new multi-cell profile with four square elements at the corner, as shown in Fig. 1(b), as well as developing an analytical solution for calculating the mean crushing force of the column. The specific energy absorption (SEA) of this new multi-cell structure was re- ported to be 1.9-times larger than that of the conventional square box column of the same cross-sectional area [8]. Recently, Zhang et al. [9] developed a theoretical solution to calculate the mean crushing force of several configurations of square multi-cell columns, as shown in Fig. 1(c), and concluded that a significant increase in energy absorption efficiency would be achieved when a square single-cell column is divided into a multi- cell column. Zhang and Cheng [10] showed a comparative nu- merical study of energy absorption characteristics between foam- filled square columns and multi-cell square columns, as can be seen in Fig. 1(d). The results showed that multi-cell columns are 50e100% more efficient in absorption energy than foam-filled columns. To improve energy absorption efficiency and minimize the initial crushing force of thin-walled aluminium columns with sin- gle-, double-, triple- and quadruple-cell columns, Hou et al. [11] optimized the structures by using single-objective and multi- objective optimizations. The single-, double-, triple- and quadruple-cell column configurations are shown in Fig. 1(e). Furthermore, Zhang et al. [12] reported the energy absorption comparison between a single column, a foam-filled column and an optimized design of a rib-reinforced column, as shown in Fig. 1(f). The results showed that the optimized design of the rib-reinforced col- umn would increase energy absorption and reduce the initial peak force. * Corresponding author. Tel.: þ62 22 2512971; fax: þ62 22 2512972. E-mail address: tdirgantara@ftmd.itb.ac.id (T. Dirgantara). Contents lists available at ScienceDirect International Journal of Impact Engineering journal homepage: www.elsevier.com/locate/ijimpeng http://dx.doi.org/10.1016/j.ijimpeng.2014.11.011 0734-743X/© 2014 Elsevier Ltd. All rights reserved. International Journal of Impact Engineering 78 (2015) 34e50