| Autor: |
Heebl, J., Lindgren, E., Melson, R. |
| Předmět: |
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| Zdroj: |
AIP Conference Proceedings; 2/22/2010, Vol. 1211 Issue 1, p1887-1894, 8p, 1 Color Photograph, 3 Charts, 5 Graphs |
| Abstrakt: |
A significant concern for the US Air Force (USAF) is the aging of its aircraft fleet and, subsequently, the resultant increase in the number of inspections required to ensure the flight-readiness and safety of these aircraft. In particular, the inspection of bolt holes at locations of high stress is a recurring requirement. Frequently, when not removing fasteners, a 45 degree angle beam shear wave ultrasonic (UT) inspection is used to detect fatigue cracks at these sites. The implementation of new inspections usually requires a capability demonstration. This is typically performed using representative damage in representative structures. It is very common to use electric discharge machined (EDM) notches to represent fatigue cracks in capability studies to decrease the time and cost of such studies. A limitation of this approach is that sensitivity will vary as a function of damage type. Therefore, a mathematical relationship needs to be developed that establishes the relationship between the responses from EDM notches and grown fatigue cracks. This will enable EDM notched samples to be used to validate new inspections. An immersion ultrasonic tank was used to perform inspections on both EDM notched samples and multiple fatigue cracked coupons using the 45 degree angle beam ultrasonic technique. Both sample sets had a range of flaw dimensions. The empirical data was analyzed to develop a mathematical transfer function that correlates the amplitude response from the EDM notches with those from grown fatigue cracks. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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