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A photomechanics material for elastoplastic stress analysis

A technique is developed whereby a polyester material and unload birefringence is used to determine stress- and strain-concentration factors

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Abstract

The object of this investigation was to develop a technique or method for elastoplastic stress analysis using the optical effects of transparent materials. Of paramount importance was the selection and characterization of a suitable model material. In particular, it was desirable that the material be able to undergo large plastic strains while, at the same time, exhibiting a suitable level of optical response.

A mixture of flexible and rigid polyester resins was found suitable, i.e., the mixture exhibited large strains and good optical response. It was found that unload birefringence (fringe order immediately upon removal of load) could be used to determine strain for a uniaxial-stress field. In particular, it provided a means for evaluating stress- and strain-concentration factors. Comparisons with other methods showed that the proposed method was reliable and gave results that are similar to those by other means.

The usefulness of the material and method for two- and three-dimensional problems awaits further study.

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References

  1. Fried, B., “Some Observations on Photoelastic Materials Stressed Beyond the Elastic Limit,”Proc. SESA,8, (2),143–148 (1951).

    Google Scholar 

  2. Frocht, M. M. and Thomson, R. A., “Studies in Photoplasticity,” Proc. 3rd U. S. Natl. Cong. Appl. Mech., 533–540 (1958).

  3. Frocht, M. M. and Cheng, Y. F., “An Experimental Study of the Laws of Double Refraction in the Plastic State in Cellulose Nitrate—Foundations for Three-Dimensional Photoplasticity,” Proc. Int. Symposium on Photoelasticity, 195–216 (1963).

  4. Mönch, E. and Loreck, R., “A Study of the Accuracy and Limits of Application of Plane Photoplastic Experiments,” Proc. Int. Symposium on Photoelasticity, 169–184 (1963).

  5. Ito, K., “Studies on Photoelasto-plastic Mechanics,”Jnl. of the Science Res. Inst., Tokyo,50,19–28 (1956).

    Google Scholar 

  6. Gurtman, G. A., Jenkins, W. C. and Tung, T. K., “Characterization of a Birefringent Material for Use in Photoelasto-Plasticity,” Douglas Rep. SM-47796 (Jan. 1965).

  7. Brill, W. A., “Basic Studies in Photoplasticity,” PhD Thesis, Stanford University (1965).

  8. Brinson, H. F., “An Interpretation of Inelastic Birefringence,”Experimental mechanics,11 (10),467–471 (Oct. 1971).

    Article  Google Scholar 

  9. Whitfield, J. K., “Characterization of Polycarbonate as a Photoelasto-Plastic Meterial,” PhD Thesis, VPI (1969).

  10. Hunter, A. R. and Schwarz, M. E., “Development and Application of Photoelasto-Plastic Method to Study Stress Distribution in Vicinity of a Simulated Crack,” NASA Contract Report 655 (1966).

  11. Hunter, A. R., Wilshaw, R. and Kyser, E., “Photoelasto-Plastic Stress Distributions in Notched Bar Configurations,” Lockheed Missiles and Space Company Report LMSC 6-78-68-24 (1968).

  12. Loreck, R., “Untersuchung von PolyestergieBharzen und anderen Kunststoffen auf ihre Eignung als photoplastisches Modellmaterial,”Kunststoffe,52,139–143 (1962).

    Google Scholar 

  13. Dally, J. W. andPrabhakaran, R., “A Class of Zero-birefringent Polymers,”Experimental mechanics,11 (1),26–31 (Jan. 1971).

    Google Scholar 

  14. Dally, J. W. andRiley, W. F., Experimental Stress Analysis, McGraw-Hill Book Co., New York (1965).

    Google Scholar 

  15. Leven, M. M., “Epoxy Resins for Photoelastic Use,” Proc. Int. Symposium on Photoelasticity, 145–165 (1963).

  16. Ramberg, W. and Osgood, W. R., “Description of Stress-Strain Curves by Three Parameters,” U. S. Natl. Advisory Committee for Aeronautics Tech. Note 902 (1943).

  17. Durelli, A. J. andSciammarella, C. A., “Elastoplastic Stress and Strain Distribution in a Finite Plate with a Central Circular Hole Subjected to Unidimensional Load,”Trans. ASME,85,Series E, (1),115–121 (1963).

    Google Scholar 

  18. Box, W. A., “The Effect of Plastic Strains on Stress Concentrations,”Proceedings of the S.E.S.A.,8 (2),99–110 (1951).

    Google Scholar 

  19. Griffith, G. E., “Experimental Investigation of the Effects of Plastic Flow in a Tension Panel with a Circular Hole,” U. S. Natl. Advisory Committee for Aeronautics Tech. Note 1705 (1948).

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Authors and Affiliations

  1. Mechanical Engineering Department, Mississippi State University, 39762, State College, Miss.

    D. H. Morris (Assistant Professor)

  2. Engineering Mechanics Department and Engineering Research Institute, Iowa State University, 50010, Ames, Iowa

    W. F. Riley (Professor)

Authors
  1. D. H. Morris
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  2. W. F. Riley
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Morris, D.H., Riley, W.F. A photomechanics material for elastoplastic stress analysis. Experimental Mechanics 12, 448–453 (1972). https://doi.org/10.1007/BF02328814

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  • DOI: https://doi.org/10.1007/BF02328814

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