Estimation of the crack-growth resistance of structural materials in the stage of stable crack growth

We studied some methodical problems connected with the estimation of crack-growth resistance of structural materials in the stage of stable crack growth. We propose a new simplified method for the construction of J(R)-curves, which enables one to attain a significant decrease in the laboriousness of the method of ''partial unloading'' and to improve the accuracy of the determination of the time of crack initiation. The algorithm of numerical calculations suggested in the present work can easily be realized in the form of a computer program. This method was successfully applied to the investigation of crack-growth resistance of 15Kh2NMFA and 15Kh2MFA steels and their welded joints. It is shown that the method under consideration is applicable to the analysis of actual practical problems.