In-plane behavior of arc-walled hexagonal honeycombs

• Three deformation modes are identified in arc-walled hexagonal honeycombs subjected to in-plane compression at various impact velocities. • The critical velocities at which the deformation transitions occur have been found to be dependent on the geometry of the cells. • A theoretical model is developed to predict the plateau stress of the arc-walled hexagonal honeycombs under compression at high impact velocities. • The arc-walled hexagonal honeycombs (C60, C90 and C120) demonstrate enhanced in-plane dynamic plateau stress, total energy absorption ( EA ), and specific energy absorption ( SEA ) compared with the traditional hexagonal honeycomb (S). Honeycombs show high specific strength and energy absorption capacity. However, the in-plane dynamic performance of curved hexagonal honeycombs has not been adequately investigated. This study investigates the in-plane compressive behavior of advanced arc-walled hexagonal honeycombs, characterized by additional arc walls and lens-shaped cavities. Finite element models were developed to evaluate the in-plane compressive performance of the proposed honeycombs subjected to in-plane compression. Parametric study was performed to examine the effects of impact velocity, wall thickness, and arc angle on the mechanical behavior of the proposed honeycombs. Three deformation modes, “X”, “V”, and “I”, were identified at low, moderate and high velocities. Plateau stress and energy absorption capacity were improved with the increase in the impact velocity and wall thickness. The arc angle also showed an enhancement effect on the plateau stress, energy absorption ( EA ) and specific energy absorption ( SEA ), particularly as it increased from 0° to 60°. Based on the repeatable collapsing mechanism proposed by Hu and Yu, a theoretical analysis was performed to evaluate the plateau stress of the proposed honeycombs subjected to in-plane compression at high velocities with an average discrepancy of 8.12%. The incorporation of arc walls in hexagonal honeycombs demonstrates enhanced plateau stress, EA , and SEA , with improvement ratios of up to 172 %, 152 %, and 41 %, respectively, relative to the traditional design. These improvements arise from the additional arch walls which generate lens-shaped cavities, which, despite adding mass, offer superior performance compared to the traditional honeycomb under dynamic compression at high velocities.