An experimental investigation of fatigue crack growth and shape development of coalescing cracks

Book · Sun Dec 01 04:00:00 EST 1996

OSTI ID:403648

Bell, R ^[1]; Harrington, D S ^[2]

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1. Carleton Univ., Ottawa, Ontario (Canada). Dept. of Mechanical and Aerospace Engineering
2. Kelley Atlantic, Bowmanville, Ontario (Canada)

The coalescence and recharacterization of two adjacent semi-elliptical cracks as they evolve into a single crack has for some time been an interesting and challenging research topic. The design codes which provide guidance on the treatment of fatigue crack growth and coalescence are the ASME Boiler and Pressure Vessel Code Section XI and the British Standards Code PD6493 and it has been shown that these procedures are often overly conservative. This paper presents results from an experimental program which investigates the fatigue crack growth and coalescence of several collinear semi-elliptical cracks. So far the coalescence process which encompasses a significant portion of the total fatigue life is not clearly understood, therefore this investigation studies in detail the crack shape development of coalescing cracks. Experimental results of fatigue crack growth and crack shape development, including the coalescence phase, are presented for semi-elliptical surface cracks in steel plate specimens loaded in four point bending. In these tests the fatigue crack growth and crack shape development are monitored using a novel mobile DCPD (direct current potential drop) probe arrangement.

• OSTI ID: 403648
• Report Number(s): CONF-9606279--; ISBN 0-7918-1492-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRACK PROPAGATION
CRACKS
EXPERIMENTAL DATA
FATIGUE
MANGANESE STEELS
MECHANICAL TESTS
MORPHOLOGY
OFFSHORE PLATFORMS
PIPELINES
PRESSURE VESSELS
SERVICE LIFE