Enhancing GFRP Laminate Strength with MWCNT Modification: Fatigue Behavior Analysis with SEM outcomes

Abstract

Thermoset resins are widely recognized for their inherent brittleness. To mitigate this issue, certain filler materials are commonly employed to enhance their strength. In this study, we sought to disperse multiwalled carbon nanotubes with a purity of 99.99% into thermoset resin and evaluate the fatigue life of the resulting samples under tension-tension mode at varying stress levels. All samples were manufactured using both modified and unmodified thermoset resin, reinforced with 250 GSM of stitched woven rovings fabric, and machined as a cross ply with 7 layers. To determine whether the samples met reliability criteria, a two-parameter Weibull distribution was employed to model the life data. Starting from the null hypothesis, the suitability of the distribution for the fatigue data was validated using the Kolmogorov-Smirnov goodness-of-fit test. The analysis revealed that the fitted distribution fell within an acceptable range, and the hypothesis was accepted with a significance level of 0.05%. Furthermore, a comparison between the unmodified and modified samples, considering various percentages of nanotube distribution, demonstrated that the slope parameter for both types of samples remained within an acceptable range. Consequently, the reliability of the samples was ensured, with the distribution meeting the 0.05% significance level. All specimens were subjected to fatigue testing using a 100 kN fatigue-rated universal testing machine at an ambient condition and a frequency of 3 Hz.