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Due to its high strength and low weight properties, structural components made from carbon fiber reinforced composites (CFRCs) are increasingly being utilized in the automotive, aerospace, and wind power industries. A common matrix material for these composites is epoxy resin, which it is very brittle in nature and limits applications of these CFRCs. Introducing rubber fillers is known to increase the toughness of epoxy resin, but is at the expanse of strength and modulus. However, nanosilica particles have been known to increase mechanical properties when added to epoxy resin. Therefore, this research focuses on the effects of introducing both core-shell rubber elastomer nanoparticles and nanosilica particles into the matrix to form a hybrid carbon fiber reinforced epoxy nanocomposite. The nanoparticles were dispersed into the epoxy resin through high shear mixing and the composites were manufacturing using the Vacuum Assisted Resin Transfer Molding (VARTM) process. Analyzing the dispersion and structure of the resulting nanocomposites was done using a scanning electron microscope (SEM). Furthermore, the static mechanical and fatigue properties were characterized. In characterizing the fatigue, a S-N curve and stiffness degradation model was developed. The hybrid showed increases in tension, flexural, and inter-laminar shear strength compared to the control composite. The hybrid also showed significant enhancements in fatigue life and stiffness degradation when compared to the control composite, as well as composites containing only the core-shell or silica nanoparticles. This research could further support future work related to the expansion of carbon fiber reinforced nanocomposites structural application in the automotive, aerospace, and wind power industries. [ABSTRACT FROM AUTHOR]

Carbon-fiber composites are increasingly being considered to replace metals in both aerospace and automotive applications due to the relative weight savings they offer. In order to qualify for such demanding applications, composite materials are subject to meet the requirements of damage tolerance and durability. However, thermoset resins based carbon fiber composites are typically not at par with metals in these properties, measured as toughness and fatigue resistance. Solutions to improve such properties do exist and are used in aerospace parts, but they come at high loading levels of resin modifiers and significant additional cost, which makes them infeasible for high volume applications. Nanosilica based resin modifiers have been shown to improve toughness and fatigue properties in carbon fiber composites, when used to modify the epoxy resin used in its matrix. In this paper, we demonstrate that the toughness and fatigue performance of both glass and carbon fiber composites can be improved when nanosilica is used at less than 1% loading to modify the fiber sizing. This approach offers a cost-efficient method to improve the toughness and fatigue performance of composites for lightweight transportation applications, without any additional processing or cycle times. [ABSTRACT FROM AUTHOR]