국내 최대 기계 및 로봇 연구정보

기술보고서

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타이틀	Repeatability and Reproducibility of Compression Strength Measurements Conducted According to ASTM E9
저자	Luecke, William E.;; Ma, Li;; Graham, Stephen M.;; Adler, Matthew A.
Keyword	ALUMINUM;; COMPRESSION TESTS;; COMPRESSIVE STRENGTH;; CYLINDRICAL BODIES;; ELASTIC PROPERTIES;; EXTENSOMETERS;; FINITE ELEMENT METHOD;; MODULUS OF ELASTICITY;; REPRODUCTION (COPYING); STRESS-STRAIN RELATIONSHIPS
URL	http://hdl.handle.net/2060/20110007223
보고서번호	M11-0102
발행년도	2010
출처	NTRS (NASA Technical Report Server)
ABSTRACT	Ten commercial laboratories participated in an interlaboratory study to establish the repeatability and reproducibility of compression strength tests conducted according to ASTM International Standard Test Method E9. The test employed a cylindrical aluminum AA2024-T351 test specimen. Participants measured elastic modulus and 0.2 % offset yield strength, YSƐ.2 % offset), using an extensometer attached to the specimen. The repeatability and reproducibility of the yield strength measurement, expressed as coefficient of variations were cv(sub r)= 0.011 and cv(sub R)= 0.020 The reproducibility of the test across the laboratories was among the best that has been reported for uniaxial tests. The reported data indicated that using diametrically opposed extensometers, instead of a single extensometer doubled the precision of the test method. Laboratories that did not lubricate the ends of the specimen measured yield stresses and elastic moduli that were smaller than those measured in laboratories that lubricated the specimen ends. A finite element analysis of the test specimen deformation for frictionless and perfect friction could not explain the discrepancy, however. The modulus measured from stress-strain data were reanalyzed using a technique that finds the optimal fit range, and applies several quality checks to the data. The error in modulus measurements from stress-strain curves generally increased as the fit range decreased to less than 40 % of the stress range.