Two-parameter fracture mechanics: Theory and applications

Technical Report · Mon Feb 01 00:00:00 EST 1993

OSTI ID:6895727

O'Dowd, N P ^[1]; Shih, C F ^[2]

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1. Imperial Coll. of Science, Technology and Medicine, London (United Kingdom). Dept. of Mechanical Engineering
2. Brown Univ., Providence, RI (United States). Div. of Engineering

A family of self-similar fields provides the two parameters required to characterize the full range of high- and low-triaxiality crack tip states. The two parameters, J and Q, have distinct roles: J sets the size scale of the process zone over which large stresses and strains develop, while Q scales the near-tip stress distribution relative to a high triaxiality reference stress state. An immediate consequence of the theory is this: it is the toughness values over a range of crack tip constraint that fully characterize the material's fracture resistance. It is shown that Q provides a common scale for interpreting cleavage fracture and ductile tearing data thus allowing both failure modes to be incorporated in a single toughness locus. The evolution of Q, as plasticity progresses from small scale yielding to fully yielded conditions, has been quantified for several crack geometries and for a wide range of material strain hardening properties. An indicator of the robustness of the J-Q fields is introduced; Q as a field parameter and as a pointwise measure of stress level is discussed.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Naval Surface Warfare Center, Annapolis, MD (United States). Carderock Div.; Brown Univ., Providence, RI (United States). Div. of Engineering
• Sponsoring Organization: USNRC; Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 6895727
• Report Number(s): NUREG/CR-5958; CDNSWC/SME-CR-16-92; ON: TI93008836
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
FRACTURE MECHANICS
MATHEMATICAL MODELS
CRACK PROPAGATION
FRACTURE PROPERTIES
STRAINS
STRESSES
THEORETICAL DATA
DATA
INFORMATION
MECHANICAL PROPERTIES
MECHANICS
NUMERICAL DATA
360103* - Metals & Alloys- Mechanical Properties
990200 - Mathematics & Computers