Abstract
In principle, one should be able to measure elastoplastic stresses in the same manner as one does elastic stresses; i.e., measure the strains and compute the stresses from the constitutive law. In practice, this is rarely done because of the more complicated material response and the anisotropy of the plastic behavior. Further, elastoplastic stresses should be computed incrementally in the general case.
This paper presents procedures for computing stresses from elastoplastic strains measured incrementally in a test under microcomputer control. The approach is evaluated for four different materials—two obeying the assumptions of classical plasticity and two showing anisotropic behavior—by computing the stresses in a smooth specimen from measured principal strains. A useful application is presented by computing the stresses at a notch root from biaxial strains measured with laser-based interferometry.
The general conclusion is that even in situations where the material is clearly anisotropic, this approach can give a reasonableestimate of the largest local principal stress.
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References
Theocaris, P.S., “Experimental Solution of Elastic-Plastic Plane-Stress Problems,”J. Appl. Mech.,29,735–743 (1962).
Durelli, A.J. andSciammarella, C.A., “Elastoplastic Stress and Strain Distribution in a Finite Plate with a Circular Hole Subjected to Unidirectional Load,”J. Appl. Mech.,30,115–121 (1963).
Griffith, G.E., “Experimental Investigation of the Effects of Plastic Flow in a Tension Panel with a Circular Hole,” NACA TN 1705 (1948).
Keil, S. andBenning, O., “On the Evaluation of Elasto-Plastic Strains Measured with Strain Gages,”Experimental Mechanics,19,265–270 (1979).
Handbook on Experimental Mechanics, ed. A.S. Kobayashi, Prentice-Hall (1987).
Sharpe, W.N., Jr. and Wang, K.C., “Evaluation of a Modified Neuber Relation,” J. Eng. Mat. and Tech., in press.
Neuber, H., “Theory of Stress Concentration for Shear-Strained Prismatical Bodies With Arbitrary Nonlinear Stress-Strain Law,”J. Appl. Mech.,28,544–550 (1961).
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Sharpe, W.N. On the measurement of elastoplastic stresses. Experimental Mechanics 32, 62–67 (1992). https://doi.org/10.1007/BF02317987
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DOI: https://doi.org/10.1007/BF02317987