Method for determining crack resistance of structural materials at quasi-brittle fracture after stable crack growth

The cases in laboratory practice of experimental investigations of fracture toughness are considered, when as a result of the tests the determination characteristics of fracture toughness ( K JC , J C , J R -curves, δ R -curves) cannot be performed correctly in accordance with the requirements of existing standards. A simplified technique for constructing J R -curves has been developed, allowing in these cases to obtain the necessary characteristics of crack resistance ( J R -curves, J 1C , J C , δ R -curves) and thereby significantly increase the information content of the tests carried out. Methodological recommendations on conducting tests and processing of their results are given. Approbation and verification of the proposed method have been carried out.