Reliability Analysis of an Electrical Cable Supporting Standoff in an Airplane
Date Issued
2010
Date
2010
Author(s)
Wang, Ying-Chieh
Abstract
Aviation safety is a very important issue in the world. Raising the ability for investigating aviation accidents can improve the aviation safety greatly. The major purpose of the present thesis focuses on a case study of a smoke-and-fire accident occurred in an airplane caused by a broken standoff that supports a few electrical cables. Mechanics behaviors of the standoff are studied in three aspects including static, fatigue, and random vibration analysis. Finite element analysis is employed and the loading uncertainty is taken into consideration. Reliability analysis is also included to accounts for the output uncertainties and quantifies the analytical results. Under reasonable and appropriate assumptions including a mean load of 44.5 N and a standard deviation of 4.45 N, it is found that failure probability of the standoff is 4.07×10-12 if static analysis is considered, and its fatigue life is 441,512 cycles if fluctuating loads are considered. As for the random vibration analysis, it is found that the first few natural frequencies of the standoff lie in the range between 0 and 3,000 Hz. If the base of the standoff is subjected to a band-limited white noise excitation within this range and having a constant magnitude of 816.88 (mm/s2)2/Hz, the failure probability of the standoff is 8.07×10-7. From all studied three mechanics aspects, it is concluded that the studied standoff should be safe when subjected to an average load of 44.5 N or lower.
Subjects
Aviation safety
Standoff
Reliability
Finite element analysis
Loading uncertainty
Random vibration
Type
thesis
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