TRANSVERSE FIBRE DEBONDING IN REINFORCED THERMOSETS - A REVIEW - 2. PROPAGATION OF TRANSVERSE CRACKS AND METHODS OF REDUCING TRANSVERSE FIBRE DEBONDING.

In this continuation of a series of articles, the author discusses factors affecting damage in GFRP exposed to stresses. It is demonstrated that as the stress level applied to a glass fiber reinforced laminate increases the number of debonded fibers increases and resin cracking becomes evident. This damage can cause weeping of pressure vessels at stress levels less than the rupture strength of the vessel. During cyclic loading the extent of damage increases during each cycle. Several techniques to assess the amount of damage have been reported. Increasing the fracture toughness of a brittle resin by the inclusion of rubber particles or by a proportion of a flexible resin has little effect on suppressing transverse fiber debonding. Other methods, such as the use of fine particulate fillers as a third phase, or coating the fibers with an inner layer of a more flexible resin, which have been reported to improve the strength and stiffness of laminates may delay the initiation of transverse fiber debonding.