The effect of temperature and loading rate on the mode II interlaminar fracture properties of a carbon fiber reinforced phenolic

The combined effect of varying loading rate and test temperature on the mode II interlaminar fracture properties of a carbon fiber reinforced phenolic resin has been investigated. End notch flexure tests at room temperature have shown that this composite offers a relatively modest value of G_IIc^NL at non-linearity and that its interlaminar fracture toughness decreases with increasing loading rate. As the test temperature is increased, the quasi-static value of G_IIc^NL increases steadily and the reduction in G_IIc^NL with loading rate becomes less dramatic. At temperatures approaching the glass transition temperature of the phenolic matrix, the interlaminar fracture toughness of the composite begins to increase sharply with crosshead displacement rate. A more detailed understanding of the effect of varying the test conditions on the failure mechanisms occurring at the crack tip of these interlaminar fracture specimens has been achieved using the double end notch flexure (DENF) geometry.