Fatigue Analysis of Polyester Composite Plate Reinforced with Carbon Fiber and Nano Silicon Dioxide

This research investigates the effect of silicon dioxide nanopowder, with particle sizes ranging from 20 to 30 nm, on the fatigue durability of carbon fiber/polyester composites.A series of fatigue experiments were conducted to assess the lifespan of the samples, which were created using varying amounts of nano silicon dioxide (SiO) at weight percentages of 0.16%, 0.20%, and 0.24%, while maintaining a carbon fiber weight fraction of 55%.The study details the properties of the composite material based on these different weight percentages.The experimental results indicated that reinforcing the carbon fiber/polyester composite with silicon dioxide nanoparticles improved its fatigue life across various ratios.The fatigue tests were conducted using a bending alternating method with fully reversed loading (R = -1).The specimens, with a thickness of 7 mm, were tested in a room temperature environment.Fatigue life was evaluated at three distinct stress amplitudes: the first level comprised 78.43, 92.98, and 106.16MPa; the second level included 87.65, 103.91, and 118.64 MPa; and the third level featured 98.59, 116.89, and 133.45 MPa.The fatigue behavior was described using the Basquin equation.The results showed that, at a weight fraction of 0.16%, an increase in stress rate of 14.03% resulted in a decrease in cycles of 12.43% at the first level and 11.34% at the second level.A similar stress rate reduction at the third level led to a 9.4% decrease in cycles.Higher stress amplitudes significantly shortened life cycles.For the 0.20% additive, an increase in average stress by 14.03% reduced life cycles by approximately 12.43%.Further stress increases at the second level led to an 11.34% decline in cycle count, while the same increase resulted in a 9.35% decrease in cycles.Fatigue evaluations on samples with 0.24% of nanoparticles showed a 14.03% increase in the stress ratio, which consequently resulted in a decrease of fatigue cycles by 7.5% at the first level, 8.3% at the second level, and 9.4% at the third level.This minor change suggests improved durability against failure with the incorporation of 0.24% nano silicon dioxide (SiO) as stress levels increased.Scanning electron microscope (SEM) images of the composite samples at a magnification of 2.0 kx demonstrate a homogeneous dispersion of nanoparticles within the microstructure, enhancing the mechanical properties of the composites.