EAGER: Damage Evolution at the Fiber-Matrix Interphase for Early Failure Characterization in Composites

Oklahoma State University, Stillwater OK

Investigators

Abstract

This EArly-concept Grant for Exploratory Research (EAGER) award supports fundamental research to understand how fatigue failure originates at the interaction between fibers and matrix in a composite material. Composites are materials made from more than one component, such as carbon or glass fibers placed in a plastic matrix. Such materials are used in several applications including aircraft, automobiles, bridges, and even golf clubs. Unfortunately, composite materials can fail catastrophically with little warning when subjected to cyclic loading. This is known as fatigue failure and can be very difficult to predict. By understanding how this failure originates and grows over time it will become possible to make better predictions about how long something made from composites can survive before breaking. This will make composites safer and cheaper to use, save lives, and benefit the US economy. This project will also help broaden the participation of traditionally groups in science and engineering. This research focuses on a fundamental characterization of the micro- and nano-scale deterioration, damage, and failure mechanisms that occur at the fiber-matrix interface and within the interphase region of polymer matrix composite materials. These measurements could then be used to develop mechanics-based design tools that incorporate the effects of fiber-surface modification on the fatigue life and durability of composites. The research is driven by the development of recent tools that enable such direct measurements at spatial resolutions of `tens of nanometers'. This investigation also leads to a more comprehensive project to develop a multi-scale damage-based approach for modeling the long-term durability of fiber-reinforced composites.