FATIGUE BEHAVIOR OF CARBON-FIBER REINFORCED-PLASTICS

This paper presents a comparison of the fatigue behaviour of several varieties of carbon fibre reinforced plastics (cfrp), emphasizing the differences between some of the older, conventional materials consisting of xas fibres in Ciba-Geigy Fibredux 913 and 914 epoxy resin matrices, and newer materials based on intermediate modulus (im) fibres in toughened resins. It is shown that the fatigue response of these materials follows a relatively simple pattern which implies that the shape of the stress (or strain) vs. life curve is determined largely by the tensile failure strain of the composite in question. This pattern appears not to be restricted to carbon fibre composites, as demonstrated by reference to results for plain aramid and glass fibre reinforced plastics, for carbon/aramid hybrids, and for materials with unidirectional, 0 90, and [(±45,0,0)2]s lay-ups. The majority of the results presented relate to repeated tension cycling (R = 0.1), but some results for R ratios which include a compression component are also discussed. © 1990.