Material Allowables for High Cycle Fatigue in Gas Turbine Engines
Abstract
HCF failures in materials used in both static and rotating components of gas turbine engines have often been found to be attributable to fatigue loading on materials which have sustained some type of damage. Damage can be present from initial material or manufacturing defects, or can develop during service operation. In-service damage, while not catastrophic by itsel?, can degrade the HCF resistance of the material below that for which it was designed. Three major sources of in-service damage which can alter the HCF capability individually or in conjunction with one another are low cycle fatigue (LCF), foreign object damage (FOD), and contact fatigue. Other types of damage include creep, corrosion and fl%ermal fatigue. The present design methodology is highly empirical and relies heavily on service experience to establish material allowable knockdown factors for each type of damage. To reduce HCF failures, the U.S. Air Force is developing a damage tolerant approach which addresses these issues in a less empirical manner. The effects of damage on HCF capability and a discussion of the material allowables under HCF are presented.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2000
- Accession Number
- ADP010636
Entities
People
- T. Nicholas
Organizations
- Air Force Research Laboratory