Int. J. Vehicle Safety, Vol. 10, No. 2, 2018 187 Copyright © 2018 Inderscience Enterprises Ltd. Finite element analysis of the foam-filled bitubal circular tube under multi-impact loading Fauzan Djamaluddin Department of Mechanical Engineering, Faculty of Engineering, Hasanuddin University, Gowa, South Sulawesi, Indonesia Email: fauzanman_77@yahoo.com Abstract: Crush analysis of bitubal cylindrical tubes under different impact angles (0°, 10°, 20°, 30°) is described in this paper. Finite element analysis (FEA) was used to determine numerical solution of double cylindrical tubes. Moreover, mass block as impactor impacted the structure in longitudinal direction of the tubes. With variations of load angle and dimensions of tube, a model of structure was developed by non-linear FEA software. The parameters such as the peak cruising force (PCF), energy absorption (EA) and specific energy absorption (SEA) are the outcomes of this study, thus it can be expected that this tube is the great energy absorber. Keywords: circular tube; oblique impact; finite element; crashworthiness; impact; foam; energy absorption; vehicle; safety; bitubal; numerical solution. Reference to this paper should be made as follows: Djamaluddin, F. (2018) ‘Finite element analysis of the foam-filled bitubal circular tube under multi-impact loading’, Int. J. Vehicle Safety, Vol. 10, No. 2, pp.187–194. 1 Introduction Nowadays, the targets of modern automobile industry are to increase the crushing ability of thin walled components and to decrease vehicle weight for fuel safety. Finding new materials and redesigneing structures are some ways to achieve these targets. In addition, simulation is the best choice because the experiment tests, namely physical vehicle test, are more costly. Some researchers study the behaviour of thin walled tubes to improve the energy absorption of material with considering variables of tubes namely the geometry, size, and cross-section. The behaviour of tubes under axial loading was studied by Alexander (1960). Thereafter, his work was continued by some scholars, for instance, the inversion and bending of tubes was studied by Reid et al. (1993) and comparing the circular and square tubes subjected to axial loading of impact was studied by Jones et al. (1989). Alghamdi et al. (2001) studied the collapsible energy absorbers in different cross- sections, in particular circular and square tubes. Cellular material such as foams and honeycombs filled the thin-walled structures to increase the energy absorption. Seitzberger et al. (1997) were the first researchers to study empty and filled foam aluminium tubes. Meanwhile, Guo et al. (2010, 2011) investigated the experimental and