Quasi-Static Compression Behavior of Dual-Material Jigsaw-Like Porous Structures

To improve the flexibility of performance regulation in traditional monolithic porous structures, a jigsaw-like porous structure was proposed. Jigsaw-like porous structures with two connection modes, namely concave connections and circular connections, were fabricated by 3D printing. Polylactic acid (PLA) and carbon fiber (CF) were used as constituent materials. Quasi-static compression experiments were carried out and combined with finite element simulation validation to investigate the effects of material type, connection mode, material arrangement pattern, and array size (3×3, 4×4, and 6×6) on the load-bearing capacity, deformation behavior, and energy absorption characteristics of the structures. The experimental results show that CF can significantly improve the peak load-bearing capacity and energy absorption performance of the structures, but it is more prone to brittle fracture at the corners and connection nodes. In contrast, PLA exhibits more stable plastic deformation characteristics. The concave connection structures have higher initial stiffness and peak load-bearing capacity, whereas the circular connection structures can effectively alleviate local stress concentration and maintain relatively stable plateau load-bearing capacity. The dual-material arrangement can change the failure path of the structures. Among the different arrangement patterns, the unit alternating arrangement exhibits superior load-bearing performance, while the row alternating arrangement demonstrates excellent energy absorption characteristics. for example, the peak force of 3×3-UA-N1 reaches 2.629 kN, which is 15.56%–34.47% higher than those of the other structures in the same group. As the array size increases, the deformation of the structures gradually evolves from overall cooperative compression to local shear instability, and the size effect becomes more significant. The peak force increases from 1.548–2.857 kN for the 3×3 structures to 1.801–3.729 kN for the 6×6 structures. The results indicate that the dual-material jigsaw-like porous structures provide a design reference for modular, lightweight, customizable protective structures and performance regulation.