Accession Number : ADA302321

Title :   Residual Stress Changes in Fatigue. Volume 1. General Discussion.

Descriptive Note : Final rept. Oct 85-Oct 90,

Corporate Author : VIRGINIA POLYTECHNIC INST AND STATE UNIV BLACKSBURG DEPT OF ENGINEERING SCIEN CE AND MECHANICS

Personal Author(s) : Dowling, Norman E. ; Dunn, DeRome O. ; Laurent, Michel P.

PDF Url : ADA302321

Report Date : 15 JAN 1994

Pagination or Media Count : 18

Abstract : The project results are summarized and discussed in general as to their significance. Portable automated X-ray stress analyzers are noted to hold some promise for field and shop work related to monitoring aircraft structure. Additions to the current software are needed, however, to make this practical. X-ray measurements of residual stress indicate an anomalous behavior of the surface layer of material where this layer appears to have a lower yield strength than the bulk material. Analysis and discussion clarifying this effect are given in Volume II of the report. Viscoplastic models of time-dependent stress- strain behavior, as discussed in detail in Volume III of this report, are noted to be primarily useful where time-dependent effects are not small. For ordinary structural alloys at near-ambient temperatures, it is recognized that cycle and time dependent transients be neglected for most routine strain-based life predictions, with the computer programs BROSE or UPLO being recommended for such use. (MM)

Descriptors :   *NAVAL AIRCRAFT, *RESIDUAL STRESS, *FATIGUE(MECHANICS), VISCOPLASTICITY, STRESS STRAIN RELATIONS, COMPUTER PROGRAMS, AIRCRAFT, LIFE EXPECTANCY(SERVICE LIFE), STRESS ANALYSIS, ALUMINUM ALLOYS, CRACKING(FRACTURING), X RAY DIFFRACTION, STRENGTH(MECHANICS), STRUCTURAL RESPONSE, AIRFRAMES, YIELD STRENGTH, FAILURE(MECHANICS), TITANIUM ALLOYS.

Subject Categories : Aircraft
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE