Estimations on J-Integral and Tearing Modulus T from a Single Specimen Test Record

Abstract

This paper presents methods for evaluating the J-integral and the tearing moduli from a single test record. Several different aspects of the problem have been combined in this work. An overview of the conditions for separability of the load into multiplicative functions of displacement and crack length as well as for the existence of η-factors is presented. The consequences of expressing J by a Merkle-Corten type formula are explored in terms of the crack increment, da, the tearing modulus, T, and J itself, including the case of growing cracks. A simple method is suggested to obtain the correct J for crack growth and T from nothing more than the test record itself; the procedure is applied to available experimental data and the results are compared with those obtained by other formulae. Additional physical interpretation is given on the Tmat-versus-Tapp stability criterion and the remaining compliance capacity CCR is defined.

Review of fracture toughness (G, K, J, CTOD, CTOA) testing and standardization

“…The second incremental equation to estimate J was obtained by Ernst et al [125] at the Westinghouse R&D Center based on the principle of load separation. Under the J-controlled crack growth conditions, the deformation theory based J-integral is independent of the loading path leading to the current displacement and crack size.…”

“…Recently, Zhu et al [140] at Battelle Memorial Institute and at the US Naval Academy obtained a functional relationship between LLD and CMOD, and developed a long overdue CMOD method for the direct evaluation of crack growth corrected J-R curves. Based on the deformation theory of plasticity and following the ideas of Ernst et al [125], Zhu et al [140] obtained a CMOD-based incremental J-integral equation in a form similar to Eq. (33) as:…”

Evaluation of Dynamic J-R Curve for Leak Before Break Design of Nuclear Reactor Coolant Piping System

“…In LBB analysis, as an integrity analysis method against instability fracture of cracked piping, J-integral, tearing modulus (J/T) method (Ernst et al, 1979(Ernst et al, , 1981 and the limit load method were used. While the limit load method is appropriate for the analysis of stainless steel piping, J/T method is appropriate for the analysis of both carbon and stainless steel piping.…”

Strain hardening and stable tearing effects in fitness-for-service assessment :

“…Extensions and modifications of the J-integral are discussed in the literature. A correction procedure [65] for J for use in J-R curve measurements has gained acceptance, but the final significance of the corrected J produced by this correction is still unclear, although it satisfies the Rice criterion for a valid expression for the J-integral during tearing.…”