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Web-reinforced foam sandwich structures have excellent mechanical properties due to the enhancement of the structural moment of inertia and the increase in the degree of integration. The present study prepared foam sandwich composites and web-reinforced foam sandwich composites through a novel thermal expansion molding process (TEMP). In addition, four conventional structures, including laminate, foam sandwich, I-beam composite, and web-reinforced foam sandwich structures, were prepared using vacuum-bag-only (VBO) technology. The feasibility of the technology was explored through the structure and properties of foam, the matching of foam and resin, and the porosity of the composites after forming. The three-point bending test showed that the stiffness and strength of the web reinforced foam sandwich prepared by TEMP technology are increased by 18.8% and 4.1%, respectively, compared with VBO technology. Moreover, the TEMP technology was more effective in processing the sandwich composite compared with the VBO technology. The failure mechanisms of the web-reinforced foam sandwich composite for the three-point bending experiment were determined by finite element analysis (FEA), and the accuracy of the finite element model was verified. The TEMP technology involved in this research provides guidance for the application of complex web-reinforced foam sandwich composites in the field of lightweight. [ABSTRACT FROM AUTHOR]

The fiber-reinforced composite (FRP) shaft need to consider vibration performance of the transmission system to improve work efficiency, comfort, service life and safety. The fiber materials and tubes containing metal connectors are important parts of the FRP shaft so that the study on the vibration performance of these two key components is of great significance for an in-depth understanding of the vibration performance of shafts. The finite element analysis (FEA), pulse vibration excitation technique (PVET) and formula computing were used to study the effect of the vibration characteristics of shafts. This study revealed that increasing the modulus of the fiber is one of the effective methods to increase the natural frequency of the FRP tube and the damping ratio of the carbon FRP tubes were slightly smaller compared with basalt and glass fiber. The FEA of FRP tube results were not distinct from the measured and calculated results so that these FEA results were relatively reliable. The damping of the tube with metal flanges at both ends were weaken compared the FRP tube. This work will be of great significance to the optimization design of the vibration performance of FRP shafts. [ABSTRACT FROM AUTHOR]