A NOTE ON HELICOPTER ROTOR-BLADE FATIGUE-CRACK PROPAGATION RATES UNDER EQUIVALENT-LIFETIME FATIGUE LOADINGS
Abstract
Results are given for a brief investigation of the relative rates of fatigue-crack propagation obtained in helicopter-rotor-blade fatigue tests in which simplified, equivalent-total-lifetime, fatigue-test loadings at zero mean load are used to simulate a flight fatigue loading that includes a mean tension load. The conventional equivalent-lifetime loadings do not give equivalent rates of crack propagation. For typical rotor-blade loadings, which included large mean tension load, the general trend was toward greatly reduced rates of fatigue-crack propagation under the equivalent-lifetime loadings provided a nonconservative basis for establishing rotor-blade inspection intervals. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1962
- Accession Number
- AD0271897
Entities
People
- John F. Ward
Organizations
- National Aeronautics and Space Administration