Accession Number:

AD0271897

Title:

A NOTE ON HELICOPTER ROTOR-BLADE FATIGUE-CRACK PROPAGATION RATES UNDER EQUIVALENT-LIFETIME FATIGUE LOADINGS

Descriptive Note:

Corporate Author:

NATIONAL AERONAUTICS AND SPACE ADMINISTRATION WASHINGTON D C

Personal Author(s):

Report Date:

1962-02-01

Pagination or Media Count:

1.0

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

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE