Accession Number : AD0882615

Title :   Research on Exploratory Development of Nondestructive Methods for Crack Detection. Part IV.

Descriptive Note : Final rept. 1 Oct 69-31 Aug 70,

Corporate Author : ARVIN SYSTEMS INC DAYTON OH

Personal Author(s) : Schroeer, Rudi M. ; O'Keefe, Frank ; Sirkar, Partha

Report Date : JAN 1971

Pagination or Media Count : 99

Abstract : Results of a research study devoted to exploratory development of a non-destructive method for crack detection are reported. The method investigated is based upon and Acoustic Impact Technique (AIT), which consists of the analysis of the vibrations in the test specimens produced by mechanical pulses. Specimens of 6061-T6 aluminum and D6ac steel were fatigue while their acoustic impact responses were measured in order to correlate their AIT responses with the beginning and growth of cracks. In several instances the beginning of subsurface defects that could only be verified by metallographic examination were indicated by the AIT measurements. The influence of metallurgical conditions upon the Acoustic Impact Technique was investigated. Specimens of 4340 steel and 2024 aluminum, having various metallurgical treatments, were AIT tested and their signal responses analyzed. Fatigue tests made on 1020 steel and 6Al-4V titanium specimens showed a common pattern in the function: Bending Fatigue Cycles vs AIT Signal Responses. (Author)

Descriptors :   (*NONDESTRUCTIVE TESTING, CRACKS), TEST METHODS, SHOCK WAVES, IMPACT TESTS, FATIGUE(MECHANICS), ALUMINUM ALLOYS, STEEL, TITANIUM ALLOYS, DAMPING, DETECTION.

Subject Categories : Aircraft
      Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE