Crushing and energy absorption properties of additively manufactured concave thin-walled tubes

�� 2022 The Authors. Published by Elsevier. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher���s website: https://doi.org/10.1016/j.rineng.2022.100424Developing an innovative protective structure with excellent energy absorption performance is a continuous research effort. The emerging additive manufacturing techniques allow fabricating structures with complex geometrical shapes which have the potential to yield unprecedented energy absorption properties. Accordingly, in this paper, the crush and energy absorption behaviour of new designs, namely Concave Tubes (CTs) featuring inwardly curved sidewalls, is assessed experimentally and compared to that of Standard tubes (STs) featuring straight sidewalls. Tubes with different geometrical configurations, including concave circular (CC), concave square (CS), standard circular (SC), and standard square (SS), are fabricated using the Selective Laser Melting (SLM) process from AlSi10Mg aluminium powder and then crushed axially under quasi-static loading. It was found that the tubes have fractured and developed a splitting deformation mode, instead of progressive buckling, during the axial crushing resulting in relatively low energy absorption performance. The experimental results revealed superior energy absorption performance for the CTs over the STs. A Multi-Attribute Decision Making (MADM) technique known as Complex Proportional Assessment (COPRAS) is used to identify the best design. The COPRAS results show that the CC design is the best energy absorbing tube outperforming all other configurations presented in this paper.Accepted versio