Journal Published Online: 01 May 1999
Volume 27, Issue 3

On the Determination of Using the Stretch Zone Width Method

CODEN: JTEVAB

Abstract

The stretch zone width ( SZW = 12 CTOD , the crack tip opening displacement) method for determining JIC involves fewer specimens and lesser size restrictions compared to the con ventional J-R curve method. However, the accuracy of the SZW-based procedure depends on each term of the J-CTOD relationship, i.e., JIC = m σ CTODC . This paper presents a numerical investigation of the J-CTOD relationship, which has been carried out using a large-deformation finite element method (FEM). The slope of the blunting line (m) is computed for various combinations of yield strength-to-elastic modulus ratio ( σo E ), power law strain-hardening exponent (n), and different measures of stress (σ in the J-CTOD relationship). This work brings out the importance of the correct choice of the stress measure, and the one suggested here is the integral average of the flow stress [σ* = 0ε* σ dε/ 0ε* dε] . Also, an effective CTOD approach is numerically validated where a sharp fatigue precrack of fracture specimens can be substituted by one with a finite notch root radius without loss of accuracy in JIC.

Author Information

Suresh, RKV
Osmania University, Hyderabad, India
Ramakrishnan, N
Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, India
Srinivas, M
Defence Metallurgical Research Laboratory, Kanchanbagh, Hyderabad, India
Ramarao, P
Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
Pages: 8
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Stock #: JTE12161J
ISSN: 0090-3973
DOI: 10.1520/JTE12161J