Axially crashworthy performance of thin-walled tubes with various configurations under the same scale

Thin-walled tubes with various design strategies as energy absorbers have been widely proposed and applied in the engineering fields. However, the comparison of the crashworthy performance of tubes with various cross-sectional topologies under axial compression remains scarce. In this paper, twelve types of thin-walled tubes (e.g., single-celled, bi-tubular and hierarchical square, hexagonal and circular tubes), which have the identical material, height, apparent area and mass, have been fairly compared. Validation is accomplished through axial quasi-static crushing tests, ensuring the accuracy of the finite element models. The crushing behaviors of all tubes studied are investigated using six crashworthiness indicators. The results show that thin-walled tubes with hierarchical features primarily deform in the preferrable stable deformation mode, with more lobes and higher energy dissipation. Then, hierarchical features can reduce the fluctuations and enhance the load-carrying capacity. In addition, the mean crushing force (MCF) and specific energy absorption (SEA) of bi-tubular tubes also do not increase significantly compared with single-celled tubes. Specifically, the increases in SEA from square tubes to circular tubes for single-celled, bi-tubular and edge-based hierarchical are 65.4 %, 75.0 % and 49.6 %, respectively. Furthermore, all tubes studied are comprehensively evaluated by applying the technique for order preference by similarity to an ideal solution (TOPSIS) method. Considering the effect of dimension, four non-dimensional indicators are selected, namely ESR, EEA, CFE and ULC. EH_C has the best overall performance among all the tubes studied.