A MODEL FOR STRESS-CORROSION CRACK-GROWTH IN GLASS REINFORCED-PLASTICS

Early models for the role of the resin matrix during acidic stress corrosion of glass reinforced plastics (GRP) are reviewed. These models stress the importance of resin toughness in resisting crack growth. While these models appear to be generally applicable, some anomalous results have been obtained for certain resin matrix systems. In this paper, some existing experimental data linking crack growth rate to applied stress intensity are re-examined and estimates obtained for stresses acting on the fibres at the crack tip. By using a model which assumes resin yielding at the crack tip, results from a variety of GRP systems are found to exhibit a common relationship between crack growth rate and applied stress. This relationship holds for resin systems that had previously not conformed with the early models regarding resin toughness. The most important conclusions of this work are that the role of the resin in resisting stress corrosion crack growth is solely to modify the stresses acting on the fibres and that subsequent crack growth rates are a function of these stresses. © 1990.