Mechanical properties of additively manufactured AlSi10Mg alloy gradient honeycomb with rib reinforcement at different strain rates

Gradient honeycomb structures exhibit excellent mechanical properties and impact resistance, showing promising potential in engineering applications. In this study, rib-reinforced gradient honeycomb structures, including wall-ribbed reinforced gradient honeycomb (WRRGH) and vertex-ribbed reinforced gradient honeycomb (VRRGH), were designed by incorporating ribs into regular hexagonal honeycombs. The in-plane mechanical properties and energy absorption capacity of these two structures, along with a uniform hexagonal honeycomb (UHH), were investigated through quasi-static compression tests (10⁻³ s⁻¹), drop hammer impact tests (220 s⁻¹), Kolsky bar tests (1500 s⁻¹), and finite element simulations. The results reveal that both WRRGH and VRRGH exhibit layer-by-layer deformation and failure modes under in-plane loading, with each gradient level's deformation mode influenced by the number and geometry of the ribs. Compared to UHH, WRRGH and VRRGH show multi-stage plateau stresses in their stress-strain curves. Under all three loading conditions, WRRGH and VRRGH significantly outperform UHH in terms of specific energy absorption (SEA). Specifically, SEA improvements for WRRGH and VRRGH under quasi-static loading are 64.5 % and 212.4 %, respectively; under drop-weight impact, SEA increases by 78.9 % and 77.9 %; and under Kolsky bar dynamic loading, the enhancements are 227.6 % and 32.79 %, respectively. Additionally, shear failure in the gradient structures becomes more pronounced at higher strain rates, indicating a strain rate-dependent failure mechanism. This work provides a new perspective for the design of rib-reinforced gradient honeycomb structures with superior mechanical and impact resistance.