Analyses Of Techniques On Structural Fatigue Failure Detection

Abstract

Machines and structures are subjected to variable loading conditions where the stress cycle does not remain the same during the operation of the machine. Fatigue is undoubtedly one of the most serious of all causes of breakdowns of machines and structures which results in sudden failures. The use of the time domain identification, the spectral density and the random decrement signature techniques in the early detection of fatigue failure have been analyzed.

The time domain identification technique identifies the characteristic roots and the number of modes from the free responses of machines and structures under test. The spectral density technique obtains a broad picture of the frequencies and energy of the structural modes of the system. The random decrement signature technique establishes standard signatures for the loading conditions of the machines and structures. These techniques are useful in detecting fatigue failure in machines and structures under irregularly varying service.

KEY WORDS: fatigue, failure detection techniques

Global Journal of Engineering Research Vol.3(1&2) 2004: 63-70