Bionic design modification of non-convex multi-corner thin-walled columns for improving energy absorption through adding bulkheads

• The difference of energy absorption among square and 20-sided-polygon column with/without bulkheads is discussed.
• A type of bionic non-convex multi-corner column is proposed to improve energy absorption.
• Numerical results show new column is more efficient and it can restrain the expansion-contraction deformation mode.
• Influence of geometrical parameters on crashworthiness is investigated.

Collapse analysis of the non-convex multi-corner thin-walled columns under axial loads illustrates that the non-compact expansion-contraction deformation mode of collapse may occur in some cases, which reduces greatly the energy absorption property of these structures. Inspired from the way by which the bamboo nodes and nodal diaphragms enhance the transverse strength of bamboo, the non-convex multi-corner thin-walled column is modified by adding bulkheads in the column for improving the energy absorption property, and a new excellent energy absorption structure named as the bionic non-convex multi-corner column (BI-NCMC) is proposed in this article, which is a non-convex multi-corner thin-walled column with bulkheads. The energy absorption of BI-NCMC has been investigated numerically. A progressive deformation mode has been achieved and this structure shows a higher energy absorption than a similar column without the bulkheads. The role of the bulkheads is to change the deformation mode from an expansion-contraction mode to a progressive mode, while the bulkheads themselves absorb little energy. The influences of parameters in the energy absorption of BI-NCMC are analyzed. It was found that the column with highest energy absorption efficiency is the one with the smallest number of bulkheads while still maintaining the progressive deformation mode.