Static compression performance of 3D printed lattice sandwich carbon fiber metal laminates

With the rapid development of the aerospace industry, composite lattice structures have attracted widespread attention owing to their lightweight characteristics at both the material and structural levels. In this work, the mechanical properties of lattice-cored fiber metal laminates were investigated by employing lightweight materials and structures. A truncated pyramid lattice structure was designed by integrating the geometric features of conventional pyramid lattices and truncated circular units. Various lattice design schemes were subsequently applied to the truncated pyramid configuration. Furthermore, by combining bionic design concepts with lightweight design principles, a novel dual-lattice bioinspired turtle-shell structure was proposed, incorporating biomimetic suture and foam-pore architectures. Finite element simulations and static compression tests were carried out to characterize the static mechanical behavior of the different lattice structures. The results showed that the 60° truncated pyramid lattice structure achieved a specific energy absorption (SEA) of 0.6 J/g at a compressive strain of 0.6. Its SEA was 1.7, 3, and 2 times that of the truncated circular, truncated cone, and conventional pyramid lattices, respectively, and was 2.2 and 1.6 times that of the 45° and 75° truncated pyramid lattices.Owing to its suture and foam-pore features, the dual-lattice bioinspired turtle-shell structure achieved a 15.58% reduction in structural mass and an SEA three times that of the truncated pyramid lattice. Overall, the 60° truncated pyramid lattice structure delivers the optimal comprehensive performance among all single-cell lattice configurations, while the proposed dual-lattice bioinspired turtle-shell structure achieves synergistic improvements in lightweight performance and energy absorption capacity. This work provides a valuable reference for the lightweight design of lattice sandwich structures in the aerospace industry.