This paper focuses on the origami metamaterials with both negative Poisson's ratio effect and high tensile performance. The research is conducted by combining experiments and numerical simulations. Parametric models are established using HyperMesh, and finite element simulations are carried out with Ls-Dyna. Nylon PA2200 specimens are fabricated by Selective Laser Sintering (SLS), and quasi-static tensile tests are performed to systematically investigate their mechanical behavior and regulation mechanism. The research shows that the unit cell geometric parameters (level, gap width) have a significant regulatory effect on the material properties: the tensile performance of the three-level structure (N3) is 413% higher than that of the one-level structure (N1), and the maximum negative Poisson's ratio reaches −0.25; reducing the gap width can increase the negative Poisson's ratio effect by 38%. The material exhibits a unique “spoon-shaped” Poisson's ratio evolution law, and the negative Poisson's ratio effect of the high-level structures (N2, N3) can be maintained over a strain range of more than 100%. When the design is extended to three-dimensional tubular structures, it is found that they have novel deformation modes such as progressive strengthening and smooth failure. This study provides theoretical and experimental basis for the development of programmable negative Poisson's ratio high-tensile metamaterials, which have important application potential in fields such as flexible electronics and aerospace.

The safe landing technology of manned spacecraft crew modules is one of the key technologies in manned spacecraft. Traditional buffer seats can effectively absorb the impact energy in the chest-back direction of astronauts, but are less effective in buffering horizontal impacts. This paper proposes a novel parallel buffer-support system to ensure the life safety of astronauts in the event of a manned spacecraft's crew module's hard landing in China's next-generation manned spacecraft. The buffer-support system has multi-directional cushioning capabilities by selecting lightweight variable cross-section hollow lattice structures as buffers, eliminating the support mechanisms such as pistons and moving pairs, and greatly improving the weight utilization efficiency of the system. Firstly, the lattice cell and buffer unit are optimized and designed, and their performance is comparatively verified through quasi-static compression tests and drop tower impact tests. Secondly, the deformation modes of the buffer unit under different oblique impact angles are discussed through simulation analysis. Finally, a finite element model of the hard landing of the crew module is established to analyze the astronaut's acceleration curves under hard landing conditions with horizontal impacts from different directions, initially verifying the feasibility of this scheme.