J-R CURVE CALCULATION WITH THE NORMALIZATION METHOD FOR TOUGHENED POLYMERS

The method of normalization is used to develop the J-R curve fracture toughness characterization for polymeric materials. This method can de velop J-R curves directly from load vs. displacement records without a need for an on-line crack monitoring system. It was used previously t o develop J-R curves for metallic materials and is applied here for th e first time to polymer materials. Single edge notched bend specimens of rubber toughened nylon 6/6 and rubber toughened amorphous nylon are used in this study. The J-R curves from the method of normalization a re compared with the results obtained from the multiple specimen metho d of ASTM Standard E813. The results show that the method of normaliza tion gives reasonable J-R curves; both methods show agreement over the early J-R curve region. In addition the J(Ic), values are determined for each method and compared. Based on this work it is suggested that the method of normalization could be used as a general test method to develop J-R curves for polymeric materials.