Deformation control and energy absorption enhancement by hierarchical dual-phase design

• Hierarchical dual-phase structure is composed of two different thickness units, and distribution of thick phase units is arranged according to lattice structures. • The mechanical properties and deformation are controlled by varying thick phase units’ distribution. • G-NPR structure shows multi-stage deformation and near zero Poisson's ratio. • The energy absorption of G-NPR structure has increased to 66.46 % compared with uniform structure. • The collapse of G-NPR structure is localized to the interior thin phase units, while the uniform structure shows global collapse. Tailoring geometric parameters and structural topology has been demonstrated to substantially enhance mechanical performance of architected cellular structures through intricate deformation control. In this study, aiming to manipulate deformation modes and enhance energy absorption performance of cellular structures, we propose the innovative hierarchical dual-phase (HDP) structures based on gyroid surfaces, featuring unit cells with thinner and thicker thickness. Non-uniform wall thickness distribution leads to changes in the local strength of the HDP structures, which will also affect the deformation mode and mechanical properties. We construct several HDP structures with the distribution of thicker thickness units referencing the topological characteristics of face-centered cubic (FCC), body-centered cubic (BCC), octagon (OCT) and negative Poisson's ratio (NPR) configurations. These structures are experimentally evaluated under quasi-static compression and drop hammer impact tests. By analyzing the mechanical responses, it becomes evident that the HDP structures offer substantial energy absorption enhancements and altered deformation modes, since the local strength of the HDP structure is highly related to the thick phase units’ distribution. Notably, the HDP structure with referencing NPR structure exhibited inward contraction with near-zero Poisson's ratio and multistage deformation, increasing energy absorption by 66.46 % over uniform gyroid structure. In terms of the dynamical mechanical responses, the HDP structure referencing NPR structure can localize the collapse into the thin phase units and exhibits good impact resistance. Additionally, to further explore the generality and effectiveness, the HDP design strategy is also employed for typical BCC and FCC structures and the mechanical properties are evaluated through compression tests. These experimental results demonstrate distinct multistage deformation patterns due to the spatial arrangement of thick phase units, leading the 70.85 % and 29.76 % increase in energy absorption performance compared to uniform FCC and BCC structures. Overall, this work fully demonstrates that the proposed HDP design can effectively manipulate the mechanical responses by adjusting the spatial distribution of dual-phase unit cells, offering a promising pathway for developing lightweight, multifunctional, and impact-resistant structures for advanced engineering applications.