Enchancement of Strength in Composites Reinforced with Previously Stressed Fibers

Abstract

Failure of a fiber in an aligned composite causes a stress wave to propagate outwards placing a dynamic overstress on the neighboring fibers. This is generally greater than the static stress concentration factor which prevails after the system has settled, and increases the probability that adjacent fibers also fail, weakening the composite. This analysis shows how weak fibers may be pre-fractured to eliminate the dynamic overstress, thereby increasing the strength of the composite. This strength enhancement is discussed with reference to the level of pre-stress, fiber variability, stress concentration factors, and size of the composite.