Crashworthiness study of multi-tube assemblies of corrugated spacer tubes based on the height difference staggered compensation method

To address the limitation of inflexible dimension parameters in thin-walled structures for ensuring energy absorption effectiveness, a design approach for a multi-tube combination of Corrugated Spacer Tubes (CST) based on a height difference staggered compensation method was proposed. The theoretical and finite element models of CST were established, and the accuracy of both models was validated through experiments. Based on the theoretical model, a design approach for the CST multi-tube combination was presented. By sequentially selecting the structural parameters of CST to induce stable and ordered circumferential deformation, consistent peak impact forces and equal intervals were ensured during axial compression. Subsequently, different CSTs with the same properties were distributed at different heights with offsets, causing the peak impact forces of different tubes to be uniformly distributed as designed within a folding wavelength, achieving a staggered compensation effect for overall smooth energy absorption. Building on this, six combination tubes were designed, and finite element models were established. The results indicate that compared to regular combination tubes, the load fluctuation of the height difference combination tubes was significantly reduced by approximately 80 %, with no significant loss in energy absorption, specific energy absorption, or mean crushing force. Moreover, the initial peak impact force was also moderately reduced. Furthermore, as the wall thickness of the CST corrugated part increased, the specific energy absorption improved by 61.5 % and 34.7 %, while the load fluctuation remained consistently low, demonstrating the effectiveness of this method in separating and compensating for CST peak impact forces.