In the present work, the nano-Aluminum oxide (Al2O3), nano-Silicon Carbide (SiC), or a hybrid of them were infused into epoxy resin with an ultrasonic system with various weight percentage ratios of the nanoparticles. Small punch testing (SPT) and indirect tension testing were adopted to measure the tensile properties of the present nanocomposites. Pin-on-ring wear testing was also performed to examine wear performance of epoxy Al2O3 and SiC nanocomposites. The Finite Element Analysis method is introduced to simulate the indirect tension test and SPT to give a complete vision of the stress distribution in the nanocomposite specimen during the loading, and to examine its mode of failure. Good agreement between the numerical and experimental results was observed. The addition of nanoparticles from Al2O3 or SiC improves the wear resistance of epoxy. Furthermore, epoxy with nano-Al2O3 has a higher wear resistance than that with nano-SiC. The tensile strength and modulus of elasticity of epoxy are reduced by adding the Al2O3 nanoparticle. The synergistic effect is not observed in the present study.

Natural fibers (NFs) have recently been the center of attention among researchers due to their low cost, availability, ease of manufacture, and potential environmental friendliness as reinforcing agents in composites. The present work deals with the mechanical behavior of palm fiber-reinforced epoxy-based composites with different weight percentage (Wt.%) ratios, ranging from 6% to 31.6%. Glass and hybrid fiber-reinforced epoxy-based composites were also examined. The indirect tensile test, i.e., diametral tensile test (DTT) and the small punch test (SPT), were used in the present work to determine the mechanical properties of the epoxy reinforced with discontinuous random oriented short fibers. Furthermore, short glass fibers were used to compare with palm fiber-reinforced epoxy. In addition, morphology observations of epoxy residue clinging to the natural fibers were carried out using the optical microscope and Scanning Electron Microscopy (SEM). The results showed that the natural fiber has a better adhesion bonding between the palm fiber/epoxy than that of glass fiber/epoxy. Therefore, adding palm fibers improves epoxy’s mechanical properties compared with synthetic glass fibers. The composite with high Wt.% of NF showed the highest diametral tensile strength (DTS), 21.74 MPa, over other composites. The DTS of composites with medium and low Wt.% of NF was lower than that of the high Wt.% by 14% and 30%, respectively.

This paper aims to assess experimentally the mechanical and tribological behavior of conventional and functionally graded (FG) polymeric matrix composites reinforced with continuous glass fibers. The small punch test (SPT) and a pin-on-disc device were used in the present work to examine the mechanical and wear behavior, respectively. The hand lay-up technique was used in the present investigation to manufacture the conventional and FG composites. Various wooden looms with different nailed spacing were employed to manufacture the FG composites. According to test type, the FG composite is composed of four and ten layers, with a different glass fiber volume of fraction (V_f%) for each layer. In addition, the finite element simulation based on Hashin’s failure criterion and cohesive zone modeling was used to show the progressive failure and give more explanation regarding the flexural behavior of such composites. The present results indicate that the wear rate of an FG composite could be affected by many factors, including the disk speed, applied load, the composite layers number, and average glass fiber volume fraction. On the other hand, the arrangement of layers in the composite materials by variation of V_f% for each layer can improve the wear rate and value of the ultimate load before the fracture of the composite material when subjected to SPT. The experimental and numerical results for all SPT specimens showed that the fracture of the SPT specimens began beneath the punch tip and grew along the fiber direction. The ultimate flexural capacity of FG composites increased by 30% compared with the conventional composites.

This study investigates the behavior of three concrete beams reinforced with steel and GFRP bars under fire exposure. The fire tests of three beams were conducted including one control steel-reinforced concrete (RC) beam and two GFRP-RC beams. The beams were exposed to fire according to the standard fire curve ISO 834 for 3 h. The investigation parameters included the reinforcement types (i.e., steel and GFRP bars) and diameter of GFRP bars. Based on the experimental results, during fire exposure, the deflection rate of the steel-RC beam was lower than the ones reinforced with GFRP bars. The critical temperatures measured at steel and GFRP bars in the steel-RC and GFRP-RC beams were 593 °C and 300–330 °C, respectively along with the fire durations of 83 and 33–36.4 min, respectively. The different GFRP bar sizes did not affect the fire resistance process. The steel-RC beam had greater fire resistance than the GFRP-RC beams. All test specimens had a fire resistance time lower than two hours. In addition, the 2D simplified finite element method (FEM) using commercial software ANSYS was performed to predict the thermal response of the beam section. Compared with experimental results, the FE model can reasonably predict the thermal responses of the beam sections.