Accession Number : AD0267780

Title :   CREEP CHARACTERISTICS OF TENSION MEMBERS IN HIGH TEMPERATURES BY USING THE PHOTO-SCREEN METHOD

Corporate Author : NATIONAL TECHNICAL UNIV ATHENS (GREECE)

Personal Author(s) : THEOCARIS,PERICLES S.

Report Date : 31 OCT 1961

Pagination or Media Count : 1

Abstract : The photo-screen method, based on the phenomenon of optical interference was developed to measure strains continuously over the whole surface of plane-strained specimens. The accuracy of the method was very high in case of large strains produced in plasticity and creep of metals. It was used to study the creep characteristics of various metals at elevated temperatures. One of 2 transparent gratings of the same pitch, mounted with the ruled surfaces in contact, was rotated slightly. The gratings was then transversed by a number of straight equidistant fringes, which are narrower and closer together the greater the acute angle between the two sets of rulings. With two gratings of equal pitch large plastic deformations could be measured. If two gratings of slightly different pitch were used then the initial interference pattern was added or subtracted from the pattern caused by the deformation of the specimen and the method was convenient to measure elastic strains with great accuracy. The method was applied to measurement of strain components of tension specimens of aluminum alloys subjected to pure tension at room temperature. The loading program was extended up to a fully plastic range. The variation of lateral contraction ratio was studied in the transition elastoplastic domain of metals. (Author)

Descriptors :   ALUMINUM ALLOYS, CREEP, DEFORMATION, HIGH TEMPERATURE, MEASUREMENT, MECHANICAL PROPERTIES, METALS, OPTICS, PLASTIC PROPERTIES, STRESSES, TENSILE PROPERTIES, TEST EQUIPMENT, TEST METHODS

Distribution Statement : APPROVED FOR PUBLIC RELEASE