关键词: 负泊松比, 超材料, 点阵结构, 泡沫混凝土, 力学性能

Abstract: This paper proposed a design method for negative Poisson ratio 3D lattice structures based on a hierarchical design concept. 3D printing technology was employed to fabricate lattice structures with varying geometric parameters, which were then combined with foam concrete slurry to form interpenetrating network composite materials. The tensile and compressive mechanical properties of both lattice structures and composite materials were investigated, and their deformation behaviors under compressive loading were characterized. Results demonstrate that the Poisson ratio of the lattice structures increases with increasing reentrant angle, reaching a minimum value of -1.46 at a reentrant angle of -30°. The absolute value of lattice structure Poisson ratio decreases with reduced unit cell size, approaching zero when the unit cell size is 2.5 mm. At an reentrant angle of -30°, the negative Poisson ratio 3D lattice-reinforced foam concrete achieves a compressive strength of 7.5 MPa (39% enhancement compared to foam concrete with identical mix proportion) and a tensile strength of 0.7 MPa (8-fold improvement over foam concrete). Strain contour map reveals that the lattice structure effectively modulates strain distribution in foam concrete, strain of foam concrete matrix is restricted through a lattice structure that generates a negative Poisson ratio effect, thereby enhancing the mechanical properties of composite materials.

Key words: negative Poisson ratio, metamaterial, lattice structure, foam concrete, mechanical property