Research on Exploratory Development of Nondestructive Methods for Crack Detection. Part IV.
Final rept. 1 Oct 69-31 Aug 70,
ARVIN SYSTEMS INC DAYTON OH
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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
- Test Facilities, Equipment and Methods