The most common failure mode for engine rotating components is material fatigue. Low Cycle Fatigue or LCF is caused by stresses and temperatures resulting from start-stop cycles. One current common practice is to assign an LCF life of certain number of start-stop cycles based on a standard flight or mission. This is done during design through detailed calculations of stresses and temperatures for a standard flight, and the use of material property and failure models. The limitation of the design phase stress and temperature calculations is that they cannot take into account actual operating temperatures and stresses. In order to improve significantly the accuracy of the LCF lifing prediction, the component temperatures and stresses need to be computed for the actual operating conditions. However, stress and thermal models are very detailed and complex, and it could take on the order of a few hours to complete a stress and temperature simulation for a flight. The objective of this work is to develop reduced models, that would enable us to compute the stresses and temperatures at critical locations, without the detailed computationally intensive models. This paper describes the development of the reduced model and the results achieved in comparison with the original models for components of Honeywell propulsion engines. Given certain inputs such as engine speed and ambient temperature for the duration of the flight, the reduced models computes the component critical location temperature and thermal stress for the same flight in a very small fraction of time it would take the original finite element model to compute.

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