Mechanical performance of vertex-based hierarchical vs square thin-walled multi-cell structure

In recent years, hierarchical structures were popularly investigated due to its significant promotion on structural strength and stiffness. In this study, the concept of vertex-based hierarchy is incorporated into multi-cell square tubes by replacing every vertex with miniature cell itself. Mechanical performance of vertex-based hierarchical vs. square thin-walled multi-cell structure were conducted theoretically and numerically, mainly in terms of total energy absorption (TEA), crush force efficient (CFE) and fluctuation degree to. A static theoretical model was constructed for vertex-based structures based on classic angle-fold element. The equation of half-wave length as well as the mean force in each fold was constructed based on the Minimal Energy Principle. Then, detailed numerical simulations were carried out by means of explicit dynamic finite element method. Based on these, further parametric studies with different scale ratios were performed and the influence of geometric configuration was determined. In addition, the explanations for promotion have been given. As the results confirmed that comparing with the conventional multi-cell structure, the vertex-based hierarchical one can evidently improve the folding response with stable compression history. The scale ratio significantly influences the specific mean force. The wall thickness shows more sensitivity on mechanical performances. All these achievements pave a way of designing novel thin-walled and light-weight energy absorption device.