Accession Number : AD0745978

Title :   An Ultrasonic Technique for Detection of the Onset of Fatigue Damage.

Descriptive Note : Annual rept. no. 1, 1 Mar 71-29 Feb 72,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICS AND MATERIALS SCIENCE

Personal Author(s) : Green,Robert E. , Jr. ; Pond,Robert B. , Sr

Report Date : JUN 1972

Pagination or Media Count : 41

Abstract : The purpose of the present research is to develop an ultrasonic technique for the detection of the onset of fatigue damage. Particular emphasis is placed on the use of ultrasonic attenuation measurements as a continuous monitor of fatigue damage during cyclic testing of metal specimens. Efforts to date have indicated that the history of attenuation during fatigue of the specimen provide an index as to the onset of failure. Ultrasonic attenuation measurements made simultaneously with fatigue tests on aluminum bars give an early warning of eminent fracture. Such a warning occurs much earlier than detection of energy reflected from the crack by conventional ultrasonic techniques. This is true for specimens which were initially defect free and for those which initially had structural defects. (Author)

Descriptors :   (*NONDESTRUCTIVE TESTING, ULTRASONIC RADIATION), FATIGUE(MECHANICS), CRACKS, ALUMINUM, ATTENUATION

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE