Energy absorption capability numerical analysis of thin-walled prismatic tubes with corner dents under axial impact

Increasing number of impacting events of many types like traffic accidents, collisions of ships or collisions of a ship either with an iceberg or ship grounding on a narrow rock, etc. induced the rapid development of the impact crashworthiness dealing with research into impact engineering problems, particularly in the field of dynamic response of structures in the plastic range and the design of energy absorbers. Since demands of general public of the safe design of components of vehicles, ships, etc. have increased substantially in the last few decades, a new challenge appeared to design special structural members which would dissipate the impact energy in order to limit the deceleration and finally to stop a moveable mass (e.g. vehicle) in a controlled manner. Such a structural member termed the energy absorber converts totally or partially the kinetic energy into another form of energy. One of the possible design solutions is the conversion of the kinetic energy of impact into the energy of plastic deformation of a thin-walled metallic structural member. In the early sixties of the 20th century, automotive safety regulations stimulated the development of the new concept of a crashworthy (safe) vehicle that had to fulfil the integrity and impact energy management requirements [2]. A designer of any impact attenuation device must meet two main, sometimes contrary requirements: The initial collapse load has to be not too high in order to avoid unacceptably high impact deceleration of the vehicle. On the other extreme, the main requirement is a possibly highest energy dissipation capacity, which may not be achieved if the collapse load of the impact device is too low. The latter may result in dangerously high occupant “ridedown” decelerations. Thus, maximizing energy absorption and minimizing peak to mean force ratio by seeking for the optimal design of these components are of great significance. There are numerous types of energy absorbers of that kind that are cited in the literature [4,6]. Namely, there are steel drums, thin tubes or multi-corner columns subject to compression, compressed frusta (truncated circular cones), simple struts under compression, sandwich plates or beams (particularly honeycomb cells) and many others. Among all those design solutions, mentioned above, thin-walled metal tubes are widely used as energy absorption systems in automotive industry due to their high energy absorption capability, easy to fabricate, relatively low price and sustainability at collapse. FERDYNUS M, KOTEŁKO M, KRAL J. Energy absorption capability numerical analysis of thin-walled prismatic tubes with corner dents under axial impact. Eksploatacja i Niezawodnosc – Maintenance and Reliability 2018; 20 (2): 252–259, http://dx.doi.org/10.17531/ ein.2018.2.10.