Accession Number : ADA017024

Title :   Advances in Fatigue Test Technology,

Corporate Author : LOCKHEED-CALIFORNIA CO BURBANK

Personal Author(s) : Ryder,J. T. ; Bowie,G. E. ; Pettit,D. E.

Report Date : FEB 1975

Pagination or Media Count : 57

Abstract : The report summarizes work directed at the verification of currently used compliance relationships for the wedge-open-loading (WOL) specimen geometry frequently used in fatigue crack propagation testing. An overview is given of compliance curve fitting procedures. A new procedure is proposed which appears to offer significant advantages. Compliance calibration results are presented for Ti-6Al-4V(RA) and Ti-6Al-4V(Beta) alloys. Analytical procedures for obtaining the stress intensity calibration function (C sub 3) from experimental compliance results were compared and the proposed three parameter fit was found to be superior. The advantages of this proposed data analysis procedure are: small numbers of constants, relationship between normalized compliance (compliance x modulus x thickness) and normalized crack length (crack length/specimen width) is differentiable and invertible, consistency with physical reasoning, and discussion of possible differences in compliance due to material differences can be restricted to a single parameter.

Descriptors :   *FATIGUE TESTS(MECHANICS), CRACK PROPAGATION, STRESSES, CALIBRATION, CURVE FITTING, TITANIUM ALLOYS

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE