Measurements of the compressive behavior of AS4/3501-6 and IM7/8551-7 carbon/epoxy

The compressive strength of carbon/epoxy materials is of importance in design, and is typically somewhat lower than the strength in tension. The measurement of compressive strength has been subject to some uncertainty, as different experimental techniques can give somewhat different results. A new specimen for the determination of compressive strength has been developed, based on compression of a 38 mm (1.5 in) diameter tube. The tube has been designed to prevent overall structural buckling and also to minimize end effects. This and a larger tubular specimen have been utilized to determine the compressive strength of AS4/3501-6 and IM7/8551-7 carbon/epoxy prepregs. The results are compared with previous tests, indicating that the results are relatively independent of the test specimen. The comparison also supports a criterion for laminate failure prediction reported previously. 15 refs., 6 figs., 1 tab.