Accession Number : ADA018635

Title :   The Effects of Rest-Time on Fatigue Crack Retardation and Observations of Crack Closure.

Descriptive Note : Final rept. May 74-Feb 75,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Sharpe,William N. , Jr. ; Corbly,Dennis M. ; Grandt,Alten F. , Jr

Report Date : AUG 1975

Pagination or Media Count : 33

Abstract : The report examines two variables which could influence fatigue crack retardation: rest periods and specimen thickness. A series of experiments are described in which a tensile overload was applied and the specimen allowed to rest at zero load prior to resuming the original cyclic loading. Since the size of the plastic zone is larger for conditions of plane stress than for plane strain, these tests were repeated for several specimen thicknesses.

Descriptors :   *Crack propagation, Retarding, Fatigue(Mechanics), Aluminum alloys, Overload, Ultrasonic tests, Loads(Forces), Stresses, Rest

Subject Categories : Metallurgy and Metallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE