In-situ Cumulative Damage Assessment in Turbine Wheels

This paper presents methodology for continuous assessment of low cycle fatigue and creep/stress-rupture damage in turbine wheels during service. The objective is to keep track of the percentage of useful turbine wheel life that has been expended. This allows preventive engine maintenance to be performed in advance of an actual system malfunction.

Variables to be monitored include exhaust gas temperature versus time, and engine speed. A microprocessor and a non-volatile memory are required for performing calculations and storing data and results.