Influence of Fiber Orientation and Content on Fatigue Crack Growth Behavior in Short-Glass-Fiber-Reinforced Polycarbonate.

Abstract

The influence of fiber orientation and content on tensile strength and fatigue crack growth resistance in short-glass-fiber-reinforced polycarbonate was investigated. The fiber volume fractions of four materials fabricated by injection moulding were 0%, 10%, 20% and 30%, and short fibers in these materials were aligned mostly in the mould-fill direction. Young's modulus and tensile strength parallel to the fiber direction were higher than those perpendicular to the fiber direction, and they increased with an increase in the fiber volume fraction. In the da/dN - ΔKl relation, resistance to fatigue crack growth was influenced by the fiber orientation and content. The resistance in L-orientation was higher than that in T-orientation, where L-and T-orientations denote crack growth perpendicular and parallel to the fibers, respectively. The resistance increased with an increase in volume fraction for L-orientation, but it was not in order of volume fraction for T-orientation. When da/dN was plotted against the stress intensity factor normalized by Young's modulus, all the data lay within the narrow band.