Document Type

Article

Publication Date

1982

Abstract

The projection moire technique affords an accurate method of measuring the geometry of the necked region in a tensile specimen. Corrections to the measured stress, necessary to account for the triaxiality introduced by the neck, require values for the radius of curvature of the specimen at the minimum section. The spacing of fringes resulting from the interference between a grating projected on the specimen surface and a master grating not only provide information which permits calculation of the radius but also demonstrates any changes in symmetry resulting from plastic deformation. Results obtained by testing specimens of copper and mild steel having initially straight and initially curved profiles indicate that Bridgman's approach provides a self-consistent correction for triaxiality. However, comparison of incremental tests with continuous tests indicates that the development of neck geometry may be sensitive to the strain rate.

Comments

Srinivasan, R., Hartley, C. S., Raju, B. B., & Clave, J., "Measurement of Neck Development in Tensile Testing Using Projection Moire," Optical Engineering, 21(4), 655-662, 1982.

Copyright 1982 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

http://dx.doi.org/10.1117/12.7972961

DOI

10.1117/12.7972961

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