Continuum and micromechanics treatment of constraint in fracture

Technical Report · Thu Jul 01 04:00:00 EDT 1993

DOI:https://doi.org/10.2172/10175312· OSTI ID:10175312

Dodds, Jr, R H ^[1]; Shih, C F ^[2]; Anderson, T L ^[3]

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1. Univ. of Illinois, Urbana (US). Dept. of Civil Engineering
2. Brown Univ., Providence, RI (US). Div. of Engineering
3. Texas A&M Univ., College Station, TX (US). Dept. of Mechanical Engineering

Two complementary methodologies are described to quantify the effects of crack-tip stress triaxiality (constraint) on the macroscopic measures of elastic-plastic fracture toughness, J and Crack-Tip Opening Displacement (CTOD). In the continuum mechanics methodology, two parameters, J and Q, suffice to characterize the full range of near-tip environments at the onset of fracture. A micromechanics methodology is described which predicts the toughness locus using crack-tip stress fields and critical J-values from a few fracture toughness tests. A robust micromechanics model for cleavage fracture has evolved from the observations of a strong, spatial self-similarity of crack-tip principal stresses under increased loading and across different fracture specimens. This report explores the fundamental concepts of the J-Q description of crack-tip fields, the fracture toughness locus and micromechanics approaches to predict the variability of macroscopic fracture toughness with constraint under elastic-plastic conditions. Computational results are presented for a surface cracked plate containing a 6:1 semi-elliptical, a = t/4 flaw subjected to remote uniaxial and biaxial tension.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering; Naval Surface Warfare Center, Annapolis, MD (United States). Carderock Div.; Illinois Univ., Urbana, IL (United States). Dept. of Civil Engineering; Brown Univ., Providence, RI (United States). Div. of Engineering; Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering
• Sponsoring Organization: Nuclear Regulatory Commission, Washington, DC (United States)
• OSTI ID: 10175312
• Report Number(s): NUREG/CR--5971; UILU-ENG--92-2014; CDNSWC/SME-CR--19-92; ON: TI93017819
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220200
36 MATERIALS SCIENCE
360103
42 ENGINEERING
420500
COMPONENTS AND ACCESSORIES
CRACKS
DUCTILE-BRITTLE TRANSITIONS
FAILURES
FINITE ELEMENT METHOD
FRACTURE MECHANICS
FRACTURE PROPERTIES
MATERIALS TESTING
MECHANICAL PROPERTIES
PRESSURE VESSELS
REACTORS