Experimental Mechanics

, Volume 30, Issue 3, pp 224–229 | Cite as

Highlights of the optical anisotropy of unstressed transparent polymeric plates

  • Sameh S. Issa


The photoelastic effect is cumulative, therefore the presence of material birefringence in unstressed transparent polymers might lead to erroneous photoelastic analyses. This presence is more influential in the scattered-light photoelasticity. Direct-transmission polariscopes are not suitable for detecting all material birefringence in normally illuminated plates because the birefringence in question coincides with the wave normal of the propagating light. The present paper describes phenomenologically the presence of the material birefringence in an arbitrarily selected group of unstressed cross-linked polymers and presents means of their determination. The material-birefringence information obtained can be used as a means of taking proper precautions for conducting faultless scattered-light photoelastic analyses. Octagonally shaped plates were machined to permit data acquisition using four different light-propagation directions. The orientation and diffusion of molecular chains appear to be the major source of the material birefringence observed.


Polymer Anisotropy Mechanical Engineer Data Acquisition Fluid Dynamics 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Pindera, J.T., Issa, S.S. and Krasnowski, B.R., “Isodyne Coatings in Strain Analysis,” Proc. 1981 SESA Spring Meeting, SEM, 111–117 (1981).Google Scholar
  2. 2.
    Issa, S.S. and Maamoun, G., “Photoelastic Isodynes as an Identifier of Transparent Plastic Materials,” ACTA-85, IMEKO, (3), 431–439 (1985).Google Scholar
  3. 3.
    Mazurkiewicz, S.B., “The Application of Scattered Light Method to the Analysis of Residual Stress in Photoelastic Models,”Oesterreichische Ingenieur- und Architekten-Zeitschrift,132 (7–8),241–243 (1987).Google Scholar
  4. 4.
    Issa, S.S., “On the Modulation of Scattered Light in Measurement of a New Parameter of Transparent Polymers,”J. Int. Meas. Conf., IMEKO, Measurement,7 (4),177–181 (1989).Google Scholar
  5. 5.
    Shelson, W. andSmith, I.W., “A Photoelastic Method Employing Scattered Light for the Solution of Plane Stress Problems,”Brit. J. Appl. Physics,7 (12),436–439 (1956).Google Scholar
  6. 6.
    Pindera, J.T. andStraka, P., “Response of the Integrated Polariscope,”J. Strain Analysis,8 (1),65–76 (1973).Google Scholar
  7. 7.
    Srinath, L.S. andFrocht, M.M., “Scattered Light in Photoelasticity-basic Equipment and Techniques,”Proc. 4th US Nat. Cong. Appl. Mech., ed., ASME, Berkeley, CA,2,775–781 (1962).Google Scholar
  8. 8.
    Lord Rayleigh, Phil. Mag., scientific papers of Rayleigh,1,87–104 (1899).Google Scholar
  9. 9.
    Dally, J.W. andRiley, W.F., Experimental Stress Analysis, McGraw-Hill Company, Inc., New York (1965).Google Scholar
  10. 10.
    Theocaris, P.S. andGdoutos, E.E., “Matrix Theory of Photoelasticity,”Springer-Verlag Berlin Heidelberg, New York (1979).Google Scholar
  11. 11.
    Aben, H., “Integrated Photoelasticity,”McGraw-Hill Company, Inc., New York (1979).Google Scholar
  12. 12.
    Issa, S.S., “Light Intensity in 3-D Photoelastic Analysis,”J. Eng. Mech., ASCE,113 (2),222–233 (1987).Google Scholar
  13. 13.
    Issa, S.S., “Beitrag zur Spannungsoptischen Untersuchung von Dicken Schalen,” Diss. Technische Hochschule, Aachen, W. Germany (1973).Google Scholar
  14. 14.
    Look, D.C., “Anisotropy of the Lateral Scattering of Linearly Polarized Light,”Opt. Eng., SPIE,28 (2),160–164 (1989).Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1990

Authors and Affiliations

  • Sameh S. Issa
    • 1
  1. 1.Civil Engineering DepartmentKuwait UniversitySafat

Personalised recommendations