Engineering topics

Davis, W. T.

Publications and source records attributed to Davis, W. T..

23 records · Page 2

NASA NTRS1974

The application of acoustic emission technique to fatigue crack measurement

The applicability of acoustic emission technique to measure fatigue cracks in aluminum alloy specimens was investigated. There are several variables, such as the metallurgical and the physical treatment of the specimen, that can affect the level of acoustic activity of a fatigue specimen. It is therefore recommended that the acoustic emission technique be supplemented by other nondestructive evaluation methods to obtain quantitative data on crack growth.

Singh, J. J.↗

NASA NTRS1974

Evaluation of acoustic emission technique for crack growth measurement in aeronautical structures

An investigation has been conducted concerning the possibility to use the acoustic emission technique for the measurement of fatigue crack growth in aluminum alloy specimens. Two types of aluminum alloys were tested in the investigation. It was found that the acoustic emission technique provides a reliable indication of changes in the crack dimensions over relatively short periods of time. The level of acoustic activity serves as an indicator of the size of the cracks.

Singh, J. J.↗

NASA NTRS1972

Effects of atmospheric aerosols on scattering reflected visible light from earth resource features

The vertical variations in atmospheric light attenuation under ambient conditions were identified, and a method through which aerial photographs of earth features might be corrected to yield quantitative information about the actual features was provided. A theoretical equation was developed based on the Bouguer-Lambert extinction law and basic photographic theory.

Noll, K. E.↗

NASA NTRS1967

Material fatigue data obtained by card-programmed hydraulic loading system

Fatigue tests using load distributions from actual loading histories encountered in flight are programmed on punched electronic accounting machine cards. With this hydraulic loading system, airframe designers can apply up to 55 load levels to a test specimen.

Davis, W. T.↗

NASA NTRS1965

System measures angular displacement without contact

Optic system coupled to an electronic detection and measuring system converts angular movement of reflected light to a direct readout, without any direct contact with the object.

Davis, W. T.↗