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Measurement of the thermoelastic coefficient of metals by strain gauges
Author(s) -
DUBOIS M.
Publication year - 1978
Publication title -
strain
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.477
H-Index - 47
eISSN - 1475-1305
pISSN - 0039-2103
DOI - 10.1111/j.1475-1305.1978.tb00260.x
Subject(s) - thermoelastic damping , strain gauge , materials science , elasticity (physics) , young's modulus , dynamometer , poisson's ratio , composite material , modulus , thermal , poisson distribution , thermodynamics , mechanical engineering , engineering , mathematics , physics , statistics
The modulus of elasticity E of metals and alloys varies, usually, when the ambient temperature θ changes, which is a drawback in most metro logic applications. A thermoelastic coefficient TCE equal to (ΔE/Δθ)/E can be defined. This article shows how this quantity can be measured, dynamometrically and statically, with safety and precision, on a metallic specimen, made of the material under study, on which strain gauges with a known thermal coefficient TCK are bonded. Experiments carried out at the ONERA Modane‐Avrieux Centre during the manufacture of more than one hundred dynamometers, made of several kinds of metals and gauges, showed that the TCKs, given by the gauge manufacturer, were more stable than the TCEs, which justifies a sufficiently fine measurement of the latter. The TCE values of six different materials, lying between ‐0.44×10 3 and + 0.33×10 3 , have been determined to within 0.02×10 ‐3 without particular precautions. An absolute precision better than 0.01×10 ‐3 may be obtained by this process, which also makes it possible to determine the modulus of elasticity E and the Poisson's ratio v.