This paper presents the experimental investigation on the progressive deformation behaviour of uni-directional pultruded composite tubes subjected to an axial impact load. Pultruded square and circular profiles with glass-polyester and glass-vinylester combinations were used for this study. Two types of triggering profiles were incorporated to investigate the effect of triggering on the energy absorption. All above combinations were investigated for three different impact velocities (9.3, 12.4 and 14m/s). The crushing peak and mean load characteristics of the composite tubes with different triggering profiles and their progressive failure modes are presented. To measure the impact velocity and the impact force, a contactless method using digital image correlation technique was adopted. The effects of the geometry profile, triggering, strain rate and the type of resin on energy absorption of the composite tubes were studied in detail.KEYWORDS: Specific energy absorption; Triggering mechanism; Crushing; Progressive failure; Composite tubes
IntroductionA great deal of research and development has been carried out in the past decades to design safer automobiles. Out of the factors considered for safety criteria, the crashworthiness has attracted significant attention due to its multiple functions. The functions of the crashworthiness structures are to (i) absorb energy, (ii) keep the occupant compartments intact and (iii) ensure tolerable deceleration levels for driver and passengers during the crash event. To meet the above functions, the automobile industry is focused on the design architecture and materials used to produce crashworthiness. As a result, different forms of the energy absorbers [1,2] and combinations of high strength metal alloys are used for crashworthiness structures. The focus on new innovative materials which yield superior strength to weight ratio [3] has been increased in order to meet the future stringent crashworthiness norms and to enhance the fuel economy target.On the other hand, there is a considerable amount of experiments [4][5][6][7] conducted on composite material to assess the energy absorption. It is a well-known fact that one can