ISSN:
1460-2695
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract— The paper addresses some aspects of the differences in fatigue crack growth rate behaviour and threshold values obtained for long through-cracks, short through-cracks and surface cracks. Attention is focused on plasticity induced closure in the wake behind the growing crack tip. For long cracks at high Kmax, closure is found to depend in a linear manner on Kmax, i.e. Kop, increases with the size of the monotonic plastic zone. Closure increases at low δK and this is primarily a consequence of the load shedding procedure. If short through-cracks are prepared by machining specimens containing long cracks, a substantial part of the plastic wake is removed and this can produce marked effects on the closure contribution during subsequent growth. The length of crack “closed” in a long crack threshold test was found to be of the order of 1 mm. Cracks less than this length exhibited “short crack” behaviour: greater than this length, they behaved as “long cracks”, with plastic wake effects apparently fully operative. Small surface cracks exhibit “long crack” behaviour at lengths as short as 0.2 mm and reasons for this are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1460-2695.1985.tb01202.x
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