Abstract
The application of an innovative noncontracting Doppler laser extensometer is presented. True axial strain has been measured during tensile tests conducted on stainless-steel metal sheets over a range of strain rates (from 10−4 to 102 1/s) and temperatures (from −40°C to 400°C). The laser radiation scattered at the surface of the specimen is recorded during the duration of the experiment. The signals are then used to determine the evolution of the axial strain, which is subsequently combined with the load signal to construct the stress-strain curve for the material. Excellent agreement has been obtained between the total elongation predicted by the laser measurements and the actual values measured from the specimens. This technique offers several advantages over traditional strain-measuring technologies.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
“Extensometer and Clip Gage Catalog,” MTS System Corporation, Minneapolis, MN (1993).
“Strain Gage Technology,” Measurements Group, Raleigh, NC (1993).
Mader, D.L., “Holographic Interferometry on Pipes,”Appl. Opt.,24,3784 (1985).
Smith, G.B., andStetson, K.A., “Heterodyne Readout of Specklegram Halo Interference Fringes,”Appl. Opt.,19,3031 (1980).
Proc. SPIE,556:Int. Conf. on Speckle, ed. H.H. Arsenault, San Diego, CA (1985).
James, M.R., Morris, W.L., and Cox, B.N., “A High Accuracy Automated Strain-field Mapper,”Experimental Mechanics,60 (March 1990).
Dai, Y.Z., Tay, C.J., and Chiang, F.P., “Determination of the Plastic Zone by Laser-speckle Correlation,” Experimental Mechanics,348 (Dec. 1991).
Sirkis, J.S., and Lim, T.J., “Displacement and Strain Measurement with Automated Grid Methods,” Experimental Mechanics,382 (Dec. 1981).
Hercher, M., Wyntjes, G., andDeWeerd, H., “Non-Contact Laser Extensometer,”Proc. SPIE-The Int. Soc. for Opt. Eng.,746,185 (1987).
ASTM E8-83, “Tension Testing of Metallic Materials”, Amer. Soc. for Test. of Mat., Section 3,03.01 (1984).
ASTM A370-77, “Mechanical Testing of Steel Products”, Amer. Soc. for Test. of Mat.,03.01 (1984).
MIL-HDBK-5E, “Austenitic Stainless Steel,” Section 9.1, “Guidelines for the Presentation of Data,” Section 9.3.2, “Typical Stress-Strain, Stress-Tangent-Modulus and Full-Range Stress-Strain Curves” (May 1989).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Bastias, P.C., Kulkarni, S.M., Kim, K.Y. et al. Noncontacting strain measurements during tensile tests. Experimental Mechanics 36, 78–83 (1996). https://doi.org/10.1007/BF02328701
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02328701