Wednesday, January 27, 2010

Functional methods

As we saw in the beginning, 2nd Section of technical diagnostics is about functional methods. They consist of:

• Evaluation of long term and short term statistical data such as, the temperature of the part/machine, Pressure of the hydraulic systems, fuel/air consumption etc… By analyzing such parameters, engineer can predict the economical use of the part/machine and prognosis future failures, so that it will be possible to remove it and put a new part/ or totally stop using the machine before a catastrophe.

• By analyzing the physical and chemical parameters such as the spectral analysis of oil in order to detect foreign particles (for example, small particles of metals can be found in oil system when a ball bearing is destroyed, and that can lead to a failure of the whole machine)

• Vibration diagnostics: where engineer analyses the vibration of machine and evaluate faults and trends. An experienced engineer watches the frequency spectrum of the vibration without even touching the machine, say where exactly problem is, and propose options to cure that defect.

Figure: An NDT engineer preparing instrumentation for a vibration analysis of a gas turbine engine