Impact behaviour of a multi-body system with energy dissipation

When a multi-body system is subjected to impact, its crashworthiness performance depends not only on the energy absorption characteristic but also on the mass distribution of the multi-bodies. In this study, experimental and numerical investigations have been carried out into the impact response of a simple multi-body system. The system consisted of two rigid movable masses and a series of several aluminium rings placed in between. The experiments were performed by making use of a conventional split Hopkinson pressure bar (SHPB) test system, but with short bars, and finite element software ABAQUS was used to simulate the collision system. Strain histories at the bars were tracked by dynamic semi-conduct gauges and deformation processes of the rings were recorded using a high-speed camera. Strain values at the characteristic points of the rings were also obtained from the FE simulation and then compared with the experiment. Contact force at the interface between the transmitter bar and ring system was obtained by a deconvolution method. Major factors which influence the energy dissipation of the collision system are discussed. A simplified analytical model was proposed to predict energy absorption and global deformation of the rings, and the response of the rigid bodies. The analytical results broadly agree well with those from the experiments and numerical simulations. This study highlights the significance of arrangement details of a multi-body system as well as its energy absorption characteristics, which will be important in designing systems with energy absorption.