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Due to its unique deformation form, Negative Poisson’s ratio sandwich structure has excellent energy absorption, but the low load capacity limits its engineering applications. In this paper, we design a new negative Poisson’s ratio rectangular tube periodic sandwich structure. There are many beams in this structure which appear plastic hinges when compressed. After further compression, the rectangular tube wall buckles and the core shrinks inward, which realizes that the structure exhibits high-performance energy absorption ability and excellent mechanical properties. Three-dimensional finite element model of sandwich structure with negative Poisson’s ratio of periodic rectangular tube quasi-static compression test and low-velocity impact were investigated by the use of ABAQUS/Explicit software. The accuracy of the simulation method was verified by the comparison of test and simulation results. Based on the validated numerical models were further investigated to comprehensively understand the influence of rectangular tube unit cell wall thickness ( t) and cell height ( h) on the load capacity and energy absorption capacity of the specimen. The energy absorption capacity and mechanical properties of the proposed negative Poisson’s ratio sandwich structure could be enhanced by optimizing the design of rectangular tube unit cell wall thickness ( t) and rectangular tube unit cell height ( h). The present findings offer insights into the application of negative Poisson’s ratio sandwich structure impact energy-absorbing structures in aerospace, automotive and other fields.

The use of fabrics in the form of grids embedded in cementitious matrices—usually termed as textile-reinforced mortar, fiber-reinforced cementitious matrix, or textile-reinforced concrete—demonstrate a more stable performance in elevated temperature conditions compared with fiber-reinforced polymers. This study investigated the residual tensile properties of bare yarns and fabrics in the form of grids embedded in a cementitious mortar after exposure to 100 °C, 200 °C, and 300 °C. Three different coated fabric textiles were used as reinforcement: carbon, basalt, and glass. Additionally, scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermos-gravimetric analysis (TGA) were conducted to evaluate potential changes in the internal structure of the fibers and the mortar. The cracking stress, the tensile strength, and the ultimate strain of the composite specimens were increased after exposure to 100 °C, while only carbon and glass fiber grids retained their effectiveness up to 200 °C. At 300 °C, the coupons reinforced with carbon and basalt fibers deteriorated rapidly. Only the glass counterparts showed an improved overall performance due to fiber contraction and the differences in the coating material. The results highlight the differences in the performance of the three fiber types and the important role of the coating material in the overall composite behavior.

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