Glass sponge-inspired ceramic graded lattices: multi-objective-driven structural optimization for mechanical design

To achieve a well-balanced mechanical performance and lightweight design of ceramic lattices, this work presents an innovative application of a multi-objective optimization framework to the gradient design of glass sponge-inspired ceramic lattice structures. Two types of graded lattices, namely diameter-graded lattice (DGL) and height-graded lattice (HGL), are proposed, and their quasi-static compressive and dynamic mechanical behaviors are systematically investigated. The results demonstrate that structural parameters significantly influence both quasi-static and dynamic mechanical properties, as well as fracture behaviors. Simulation results reveal that, as the diameter gradient factor increases, the quasi-static failure mode of the graded lattice shifts from a layer fracture mode to a global failure mode. In dynamic impact simulations, two novel energy dissipation mechanisms “layer fracture and crushed fracture” are observed under varying impact velocities. Based on these findings, a multi-objective optimization framework is developed to determine an optimal design for the graded lattice; Simulation results show that compared with the best-performing DGL, the optimal graded lattice achieves a 24% enhancement in specific energy absorption (SEA), with only slight reductions of 0.8% in specific strength and 6% in specific modulus, together with a 26% reduction in volume, indicating a balanced combination of specific strength, specific modulus, and SEA. The optimal graded lattice is then fabricated using a stereolithography (SL) system, followed by uniaxial compression tests. These tests confirm that the optimal graded lattice exhibits enhanced strength, stiffness, and energy absorption capacity. The findings of this study provide an effective strategy for the design of robust ceramic lattice structures.