Crack propagation from notches under LCF conditions at room and high temperatures

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:191355

Bui-Quoc, T; Bernard, M; Merah, N ^[1]

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1. Ecole Polytechnique of Montreal, Quebec (Canada). Dept. of Mechanical Engineering

Crack growth behavior at room temperature and at 600 C of SS 304 plates with a central circular hole is studied using linear elastic and elastic-plastic fracture mechanics concepts. Due to large local plastic zone at the hole edge, short fatigue crack propagation is strongly affected by closure phenomena, and the extension rate of a short crack could not be adequately expressed in terms of stress intensity factor {Delta}K. However, parameter {Delta}K would be appropriate for investigating the behavior of long cracks. Crack acceleration due to temperature increase is discussed and a strain-based normalization factor for {Delta}K is suggested for long cracks. The J-integral obtained from a finite element analysis is successful in establishing the propagation rate of both short and long cracks; simple power relations exist between da/dN and cyclic J-integral ({Delta}J{sub f}) at room temperature and at 600 C. With the modified J-integral, using the actual flow strain, the temperature effect could be incorporated in the correlation between da/dN and {Delta}J{sub f}.

• OSTI ID: 191355
• Report Number(s): CONF-950740--; ISBN 0-7918-1337-1
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
EXPERIMENTAL DATA
FATIGUE
STAINLESS STEEL-304
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0400-1000 K