Compressive behavior and energy absorption of SLA-fabricated resin-based bio-inspired hierarchical circular honeycombs with spiral stiffeners

Circular honeycomb structures are widely used in aerospace, architecture, and biomedical engineering owing to their high specific strength, specific stiffness, and superior energy absorption capacity. In this study, a novel bio-inspired hierarchical circular honeycomb structure with spiral stiffeners (BHCHSSS) is proposed. The specimens are fabricated using vat photopolymerization technology, and their compressive behavior and deformation modes are investigated through quasi-static compression experiments in conjunction with finite element simulations. A systematic parametric analysis is conducted to evaluate the effects of reinforcement unit type, geometric parameters of the spiral stiffeners, and the number and arrangement of stiffeners on the compressive strength, energy absorption capacity, and failure mechanisms of the BHCHSSS. Taking the traditional circular honeycomb structure (CHS) with identical wall thickness as the benchmark, the comparison demonstrates that the proposed BHCHSSS achieves a 23.85% higher compressive strength and a 19.11% larger energy absorption capacity. Moreover, the structure effectively alleviates stress concentration during load transfer, thereby avoiding excessive localized compressive stress. The compressive strength and energy absorption capacity increased with the number, height, and width of the spiral stiffeners, whereas the pitch mainly governed the balance between load-bearing capacity and deformation stability.