Improvement of Fatigue Life of Plain-Woven CFRP Modified with Enhanced Matrix with Sub-Micron Sized Glass Fibers

Abstract

This study discussed on the effect of the size of added glass fibers into the epoxy matrix on the fatigue life and its internal crack growth along carbon fiber bundle of the plain-woven CFRP (Carbon Fiber Reinforced Plastic). Static bending strength, fatigue lives and fracture toughness were measured after modification with added glass fibers. The resistance of debonding was characterized with double cantilever beam Mode-I fracture specimen. In addition, local Mode-I and Mode-II fracture toughness around carbon fiber bundle were also discussed with model specimen fabricated with carbon fiber bundle embedded in the modified epoxy matrix. Fatigue life of CFRP was dramatically 10-100 times increased by addition of sub-micron sized (close to nano-sized) glass fibers. Local Mode-I and Mode-II fracture toughness was 3-7 times improved when epoxy matrix was modified with sub-micron sized glass fibers compared with unmodified case. When the model specimen was modified with 500nm glass fibers, fatigue crack growth rate was much decreased than that with 11μm glass fibers. It was found by current study that sub-micron sized glass fibers should be selected as the enhancer to prevent internal crack for improving the fatigue life and other mechanical properties of plain-woven CFRP.