Many materials are gradually softened with increasing temperatures in the fire, which will cause severe damage. As a new fiber-reinforced polymer (FRP) composite, the change in mechanical properties of nanometer montmorillonite composite fiber-reinforced bars or plates at elevated temperatures has not been investigated. To obtain a more comprehensive study of the mechanical properties of FRP composites at high temperatures, experimental research on the nanometer montmorillonite composite fiber material under the tensile rate of 1 mm/min was conducted at target temperatures between 20 °C and 350 °C. Finally, the failure mode of the FRP composites after the tensile test was analyzed. The results demonstrate that the elevated temperatures had a major impact on the residual mechanical properties of fiber-reinforced polymer (FRP) composites when the exposed temperatures exceeded 200 °C. Below 200 °C, the maximum decrease and increase in the fracture load of fiber reinforced polymer (FRP) composites were between −34% and 153% of their initial fracture load. After exposing to temperatures above 200 °C, the surface color of fiber-reinforced polymer (FRP) composites changed from brown to black. When exposed to temperatures between 200 and 300 °C, the ultimate load of fiber-reinforced polymer (FRP) composites significantly increased from 731.01 N to 1650.97 N. Additionally, the stress−strain behavior can be accurately predicted by using the proposed Johnson−Cook constitutive model. The experimental results studied in this research can be applied to both further research and engineering applications when conducting a theoretical simulation of fiber-reinforced polymer (FRP) composites.

This study investigates the impact of specimen size on the mechanical properties of wood, specifically focusing on compression strength, elastic modulus, and Poisson's ratio. Compression tests were conducted using three different specimen sizes (20mm×20mm×30mm, 40mm×40mm×60mm, 60mm×90mm×90mm) in the longitudinal, radial, and tangential directions. Mechanical parameters, failure mechanisms, load-displacement curves, and stress-strain relationships were systematically analyzed for each size. The study also evaluated the influence of specimen size on the accuracy of finite element numerical simulations by utilizing the obtained mechanical parameters. The results reveal a significant correlation between compressive strength and specimen size, indicating a decrease in compressive strength with increasing specimen size. Conversely, elastic modulus and Poisson's ratio exhibit less sensitivity to variations in specimen size. Notably, parameters derived from small-sized specimens (20mm×20mm×30mm) exhibited substantial errors, while those obtained from medium-sized (40mm×40mm×60mm) and large-sized specimens (60mm×90mm×90mm) demonstrated greater reliability, providing precise results in finite element numerical simulations.

Deep‐space exploration requires reliable mechanical constraints for lunar materials; however, the scarcity of samples limits destructive macroscale testing. Here, we combine automated mineralogical analysis and nanoindentation to investigate the mineral‐scale mechanical behavior of two Chang'e‐5 regolith particles and a Laâyoune 002 feldspathic breccia comparison sample. Rather than treating these materials as bulk proxies for all mare and highland regolith regions, we compare analogous mineral domains using an identical testing protocol. Minerals in the Chang'e‐5 particles generally show lower elastic modulus and hardness, greater indentation depth and creep displacement, and higher plastic work ratios than analogous minerals measured in the interior polished section of Laâyoune 002. The strongest contrast occurs in ilmenite, where more plastic, energy‐dissipative deformation is observed. These measured contrasts document micromechanical differences among analogous minerals in the analyzed lunar samples. Their interpretation considers lithology, mineral chemistry, local microstructure, and impact history, with regolith processes and space‐weathering overprint as plausible contributors to the Chang'e‐5 response. First‐order homogenization of the analyzed particle‐scale assemblages yields equivalent elastic moduli of about 54 GPa for the Chang'e‐5 assemblage and about 78 GPa for the Laâyoune 002 assemblage. These results provide mineral‐resolved mechanical constraints for interpreting lunar material evolution and for designing better simulants, experiments, and multiscale engineering assessments.