The normalization method is adopted and extended in this paper to develop J-R curves for standard and nonstandard specimens directly from load versus load-line displacement test data without the need for online crack length measurement. A set of single edge notched bend (SENB) specimens with different crack lengths for an A285 carbon steel are tested according to the guideline of ASTM standard E1820, and the ability of normalization method is then demonstrated in determination of crack-tip constraint-dependent J-R curves for the SENB specimens. The results show that the normalization method can be used to determine J-R curves for the standard as well as nonstandard specimens. The resistance curve procedure and the basic procedure specified in ASTM E1820 are evaluated, and a modified basic procedure is also presented for determining the J-integral. Comparisons of the resulting J-R curves indicate that the modified basic procedure can be equivalent to the resistance curve procedure. To validate the normalization method, the conventional electric potential drop method is used to monitor crack growth and to determine the J-R curves for the A285 steel. Two equations used in the potential drop method, i.e. linear and nonlinear relationships between the crack length and the electric potential, are employed to determine the crack length during the fracture testing. It shows that the J-R curves determined with the normalization method are in good agreement with those based on the potential drop methods for all specimens considered.

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