On the Design and Crashworthiness of Tubular Protective Structures with Honeycomb-Like Cross-Sections

Honeycomb structures are predominantly in the form of cubic lattices, which presents certain limitations in protecting curve-faced structures and facilities. Tubular protective structures with honeycomb-like cross-sections, however, can provide a promising alternative. In this work, an innovative method was proposed to transform arbitrary planar cellular structures into tubular plates with cellular cross-sections. Based on this method, three types of tubular protective structures with honeycomb-like cross-sections were subsequently developed by incorporating the configurations of conventional hexagonal honeycomb, conventional re-entrant honeycomb and a re-entrant honeycomb with zigzag inclined ligaments (termed as TCHH, TCRH and TRH-ZIL, respectively). This study aims to evaluate the energy absorption performance of these structures and provide design guidance. It is observed that the non-auxetic TCHH warps under quasi-static load and low-velocity impact loads, failing to conform closely to the curve-faced protected object. In contrast, the auxetic TCRH and TRH-ZIL adapt more effectively to the curved-surface, offering excellent structural stability under impact loads. Additionally, the auxetic TCRH and TRH-ZIL exhibit superior specific energy absorption (SEA) and crush force efficiency (CFE) compared to the non-auxetic TCHH. Hence, the tubular auxetic protective structures with honeycomb-like cross-sections are ideal designs for protective cylindrical structures.