Carbon-fiber reinforced composites, with their favorable strength-to-weight and stiffness-to-weight ratios, are replacing their metal counterparts in a variety of high-performance structural applications. However, the principal limitation of such composite materials is their brittle failure and insufficient fatigue life. A new concept for fatigue-resistant carbon-fiber composites features a modified epoxy resin matrix that is infiltrated with nanoparticle additives. These nanoscale particles will be engineered to interfere with or disrupt crack propagation processes and thereby significantly prolong the fatigue life of the composite material. The ability to combat fatigue is critical for safe and reliable operation as well as reduction in the operational and maintenance costs for structural components. This will be of great benefit to the aerospace, defense, energy and automotive industries which extensively use carbon-fiber reinforced plastics. One of the emerging industries where such new fatigue-resistant materials can have high impact is in wind energy. Wind is one of the fastest growing energy technologies on the globe and enhancing the fatigue properties and the operating life of carbon-fiber composite materials used in wind turbine construction is therefore of great practical relevance.
The goal of this project is to understand the fundamental mechanisms by which the nanoparticle additives enhance the fatigue life of the composite material and to reveal how these mechanisms are affected by the geometry, interface strength, loading fraction and dispersion of nanoparticles. To accomplish this, investigators will employ an integrated modeling, simulation, manufacturing, characterization and experimental fatigue testing approach to understand and optimize the underlying mechanisms that are responsible for fatigue life improvement. To be consistent with industrial practices, researchers will manufacture pre-pregs in which microfiber plies are pre-impregnated with nanoparticle-laden epoxy resins, or in which nanoparticles are pre-dispersed on the microfibers which are then impregnated with neat resins. The fundamental knowledge gained from the above tasks will be applied to establish processing-structure-property relationships that will be used to manufacture proof-of-concept carbon fiber-reinforced composites with optimized nanoparticle geometry, loading, dispersion and interface strength. These composites will be tested to quantify and benchmark the fatigue-life improvements that can be achieved relative to the traditional composites used by industry. This project will lead to an in-depth understanding of the role of the nanoparticle geometry, surface chemistry, loading fraction and dispersion in fatigue life improvements for the next generation of carbon-fiber reinforced composites.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
