Archive for the ‘Fracture mechanics’ Category
Monday, March 20th, 2006
The fracture characteristics of welds of various aluminum alloys were evaluated by means of tear and notch-tensile tests. The tear resistance and notch toughness of welds are generally greater than those of cold-worked or heat-treated base metal, and approach those of annealed base metal.
Subsequent thermal treatment of heat treatable filler ...
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Monday, March 20th, 2006
The high temperature and/or high strength-to-weight requirements of aerospace structures, advanced propulsion systems, high-speed aircraft and deep submergence vessels have stimulated the development of certain nonferrous metals that can be used in these applications.
In addition to the failures that arise because of extreme environmental conditions, e.g., ...
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Monday, March 20th, 2006
Aluminum alloys are progressively used in the automobile industry due to several advantages such as low specific weight, good formability, good corrosion resistance and a nice surface appearance. The standard production forming processes such as extrusion and forging, can give rise to large variations in the tensile, ...
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Monday, March 20th, 2006
Analysis of failure
When studying a failure, great care must be used to avoid destroying important evidence. Detailed studies often require careful documentation of the service history (time, temperature, loadings and environment), supplemented by chemical analysis and electron micrographs. Further study of the sequence of events leading up ...
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Monday, March 20th, 2006
Many elements of fracture have been used to describe and categorize the types of fractures encountered in the laboratory and in service. These elements include loading conditions, rate of crack growth, and macroscopic and microscopic appearance of fracture surfaces.
Failure analysis often find itself useful to classify fractures ...
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Monday, March 20th, 2006
It has been recognized since 1830 that a metal subjected to a repetitive or fluctuating stress will fail at a stress much lower than that required to cause fracture on a single application of load. Failures occurring under conditions of dynamic loading are called fatigue failures, presumably ...
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Monday, March 20th, 2006
The first part of this article has introduced a number of terms dealing with brittle fracture, such as NDT, FTE, FTP, etc. The tests for determining these transition temperatures have been described. Before seeing how they are used in engineering design through the fracture analysis diagram, we ...
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Monday, March 20th, 2006
The Brittle – Fracture Problem
During World War II a great deal of attention was directed to the brittle failure of welded Liberty ships and T-2 tankers. Some of these ships broke completely in two, while, in other instances, the fracture did not completely disable the ship. Most ...
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Monday, March 20th, 2006
Ductile or fibrous fracture
The higher temperature side of the ductile/brittle transition is associated with a much tougher mode of failure, which absorbs much more energy in the impact test. While the failure mode is often referred to as ductile fracture, it could be described as rupture, a ...
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Monday, March 20th, 2006
Intergranular embrittlement
While cleavage fracture in steels is a common form of embrittlement, in many cases the embrittlement is intergranular (IG), i.e. it takes place along the grain boundaries, usually the former austenitic boundaries. This behavior is encountered in as-quenched steels, on tempering (temper embrittlement), after heating at ...
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