Fatigue Crack Growth Predictions for Simplified Spectrum Loading: Influence of Major Cycles on Minor-Cycle Damage Rates
Abstract
As part of the Engine Structural Integrity Program, USAF turbine-engine components are subject to a damage tolerance or crack-growth assessment. This assessment involves the prediction of crack-growth lifetimes from an initial flaw size under simulated mission loading. The accuracy of the prediction is dependent upon numerous assumptions and inputs: how well the actual mission is simulated by the simpler load spectrum, the accuracy of the component temperature and stress analysis, the ability to account for load-history effects and time dependency using steady-state crack- growth data, and accounting for thermomechanical fatigue crack growth using isothermal data, to name just a few. It is evident that the life prediction is a very complex problem, and numerous effects are accounted for with empirical factors based on experience and laboratory observations. However, understanding the damage mechanisms and their controlling variables is essential in improving the accuracy of crack-growth predictions, given the complex nature of the problem.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2003
- Accession Number
- ADP014138
Entities
People
- Andrew H. Rosenberger
- James M. Larsen
- Stephan M. Russ
- W. S. Johnson
Organizations
- Air Force Research Laboratory