Crack-shape effects for indentation fracture toughness measurements

Journal Article · Sat Feb 01 00:00:00 EST 1992 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1992.tb08180.x· OSTI ID:7243620

Smith, S M; Scattergood, R O ^[1]

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1. North Carolina State Univ., Raleigh, NC (United States). Dept. of Materials Science and Engineering

Various methods to measure fracture toughness using indentation precracks were compared using soda-lime glass as a test material. In situ measurements of crack size as a function of applied stress allow both the toughness K[sub c] and the residual-stress factor [chi] to be independently determined. Analysis of the data showed that stress intensity factors based on classical half-penny crack shapes overestimate toughness values and produce an apparent R-curve effect. This is due to a constraint on crack shape imposed by primary lateral cracks in soda-lime glass. Models based on elliptical cracks were developed to account for the crack-shape effects.

• DOE Contract Number: FG05-84ER45115
• OSTI ID: 7243620
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 75:2; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GLASS
FRACTURE PROPERTIES
CRACKS
MEASURING METHODS
SHAPE
STRESS INTENSITY FACTORS
MECHANICAL PROPERTIES
360603* - Materials- Properties