Fracture Resistance Characterization of Graphite/Epoxy Composites Available to Purchase

The resistance method has been applied to graphite/epoxy composites. The method is based on the assumption that the damage growth at the crack tip can be modeled as a self-similar crack extension through compliance matching. Experimental data for center-cracked tension specimens reveal a linear relationship between crack-growth resistance and initial crack length. For the [0/±45]_s laminate, the effective increment of crack length at fracture and the corresponding crack-growth resistance essentially are independent of initial crack length. The average amount of this crack extension in the [0/±45]_2s and [0/±45]_s laminates is higher than the values obtained from a best fit of fracture strength data reported in the literature. However, the present method results in an improved prediction of fracture strength for the [0/90/ ±45]_s laminate.