抄録
A simple equation of the J-integral proposed by Rice et al does not take consideration of the notch length of the test specimen, although is does into consideration the non-linearity of the materials. So, the J-integral equation which modified the effect of notch length is confirmed for brittle and porous polymeric materials, i. e. RIM Polyurethane at low temperature, in which the skin layers are removed. It is found that the equation can be applied to ductile and porous polymeric materials at a temperature of 20°C. The equation is examined by changing the specimen thickness at that temperature. It is found that the J-integral resistant curve determined by this method is independent of specimen thickness.
