Fatigue Damage, Crack Growth and Life Prediction
Fatigue Damage, Crack Growth and Life Prediction

Author: F. Ellyin

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 484

ISBN-13: 9400915098

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Fatigue failure is a multi-stage process. It begins with the initiation of cracks, and with continued cyclic loading the cracks propagate, finally leading to the rupture of a component or specimen. The demarcation between the above stages is not well-defined. Depending upon the scale of interest, the variation may span three orders of magnitude. For example, to a material scientist an initiated crack may be of the order of a micron, whereas for an engineer it can be of the order of a millimetre. It is not surprising therefore to see that investigation of the fatigue process has followed different paths depending upon the scale of phenomenon under investigation. Interest in the study of fatigue failure increased with the advent of industrial ization. Because of the urgent need to design against fatigue failure, early investiga tors focused on prototype testing and proposed failure criteria similar to design formulae. Thus, a methodology developed whereby the fatigue theories were proposed based on experimental observations, albeit at times with limited scope. This type of phenomenological approach progressed rapidly during the past four decades as closed-loop testing machines became available.

The Effects of Slip Character and Crack Closure on the Growth of Small Fatigue Cracks in Titanium-aluminium Alloys
The Effects of Slip Character and Crack Closure on the Growth of Small Fatigue Cracks in Titanium-aluminium Alloys

Author: James M. Larsen

Publisher:

Published: 1990

Total Pages: 286

ISBN-13:

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An investigation was performed to study the effects of slip character and crack closure on the propagation of small fatigue cracks in titanium- aluminum alloys. The materials examined were solution-treated Ti-4Al and Ti-8Al, as well as aged Ti-8Al. The propagation of naturally initiated surface cracks of depths as small as 25 micrometers was compared with the behavior of large through-thickness cracks. An extensometer was used to monitor crack closure throughout the large crack tests, and the closure behavior of the small cracks was measured using a computerized laser interferometric displacement gage having a displacement resolution of 0.01 micrometer. The measurements of crack closure were used to compute an effective stress intensity factor range. In all three alloys and for all test conditions, which included a range of stress levels and stress ratios, small cracks propagated faster than large cracks subjected to an equivalent Delta K, and the small cracks propagated under conditions that were significantly below the large-crack threshold, Delta K(th). Although the character and distribution of slip in Ti-Al alloys may have a dramatic influence on fatigue crack initiation and on the propagation of large cracks, this effect was minimal for small cracks.

Advances in Fracture Research
Advances in Fracture Research

Author: K. Salama

Publisher: Elsevier

Published: 2013-10-22

Total Pages: 3063

ISBN-13: 1483294064

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Held every four years, the International Congress on Fracture is the premier international forum for the exchange of ideas between scientists and engineers involved in producing and using materials resistant to fracture and fatigue. This major six-volume work which forms the proceedings of the Seventh International Congress on Fracture therefore provides the most comprehensive account available of the current status of research into fracture and fatigue, and the application of this knowledge to the design, fabrication and operation of materials and structures. As such, it will be an essential reference for materials scientists and mechanical, structural, aeronautical and design engineers with an interest in fracture and its prevention.

Advanced Structural Materials
Advanced Structural Materials

Author: Winston O. Soboyejo

Publisher: CRC Press

Published: 2006-12-21

Total Pages: 526

ISBN-13: 1420017462

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A snapshot of the central ideas used to control fracture properties of engineered structural metallic materials, Advanced Structural Materials: Properties, Design Optimization, and Applications illustrates the critical role that advanced structural metallic materials play in aerospace, biomedical, automotive, sporting goods, and other indust