SYMPOSIA PAPER Published: 01 January 1976
STP33943S

A Fracture Mechanics Approach to Creep Crack Growth

Source

A fracture mechanics approach was used to study high-temperature creep crack propagation. Crack growth rates were correlated with the C*-parameter which is an energy rate line integral. For materials conforming to a nonlinear stress and strain rate relationship in the steady-state creep range, specifically, those which can be properly idealized as purely viscous (negligible elastic and transient creep effects), C* characterizes the crack tip stress and strain rate fields.

Crack growth rate tests were conducted in the creep range on a discaloy superalloy at 1200°F (920 K). Two specimen geometries were tested, a center cracked panel and a compact geometry, to establish the geometry independence of this approach. The results showed that crack growth rate correlated with the C*-integral, while other parameters (K and nominal stress) failed to adequately characterize crack growth rate.

Author Information

Landes, JD
Westinghouse Research Laboratories, Pittsburgh, Pa.
Begley, JA
Ohio State University, Columbus, Ohio
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Details
Developed by Committee: E08
Pages: 128–148
DOI: 10.1520/STP33943S
ISBN-EB: 978-0-8031-4669-3
ISBN-13: 978-0-8031-0509-6