Abstract
A method for the determination of the fracture energy of brittle plastics is described. A crack is propagated down the length of a rectangular specimen under controlled conditions and the variation of crack opening with length determined. From these results the fracture energy may be calculated The method has been applied to determine the variation of fracture energy for polymethyl-methacrylate and polystyrene with temperature in the temperature range 20 to 80°C. The results of tests carried out at room temperature show good agreement with similar results obtained by other investigators.