Categorizing Low and High Cycle Fatigue in Turbine Engines

[Schuyler]

Request someone categorize low and high cycle fatigue in turbine engines. For example, what causes (or how do you get) high cycle fatigue vs. low cycle fatigue. I'm thinking in terms of vibration and gag cycles, etc.

 

[Aviator8691]

High cycle Fatigue has been identified as a cause of turbine engine failures. High Cycle Fatigue is fatigue that occurs at relatively large numbers of cycles and is caused by high frequency vibrations in both static and rotating hardware. The distinction between high cycle fatigue and low cycle fatigue is made by determining whether the dominant component of the strain imposed during cyclic loading is elastic or high cycle, plastic or low cycle; which in turn depends on the properties of the material and on the magnitude of the stress. Three of the principal areas of material with high cycle fatigue capability under damage states are high cycle and low cycle fatigue interactions, the role of FOD damage and fretting fatigue.

 

[jeckle]

HCF usually > 10^7 or 10^6 cycles think vibrations rotations ect. Designed to Goodman Diagram stresses less than endurance limit

LCF usually < 10^6 cycles think about cyclic loading like the pressure cycle of a planes cabin. Designed to an LCF curve component life based on stress and cycles.