Experimental Mechanics

, Volume 11, Issue 9, pp 414–417 | Cite as

A method of simultaneously recording full-field isoclinic patterns at several isoclinic angles

Paper describes a new method of viewing several full-field isoclinic patterns simultaneously
  • R. R. Parmerter
  • J. Rahn


In photoviscoelasticity, the difference in principal stresses at a point depends not only on the history of isochromatic-fringe order, but also on the history of isoclinic angle. Thus, meaningful interpretation of the isochromatic data in terms of stress cannot be made without knowledge of the isoclinic history.

When the isoclinic angle is changing rapidly, the traditional method of rotating the polarizer-analyzer pair in a plane polariscope by mechanical means is limited by practical rotation rates. Magnetic rotation of the polarization, using the Faraday effect, is possible, but suffers from the problem that the isoclinic patterns are viewed sequentially. This limitation is also inherent in the slower mechanical-rotation method.

This paper describes a new method of viewing several full-field isoclinic patterns simultaneously. Thus, the recording system has more time to make each record, and requirements on film speed and framing rates may be relaxed by an order of magnitude.


Mechanical Engineer Fluid Dynamics Traditional Method Principal Stress Framing Rate 
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Copyright information

© Society for Experimental Mechanics, Inc. 1971

Authors and Affiliations

  • R. R. Parmerter
    • 1
  • J. Rahn
    • 2
  1. 1.Department of Aeronautics and AstronauticsUniversity of WashingtonSeattle
  2. 2.University of WashingtonSeattle

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