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Experimental Mechanics

, Volume 3, Issue 9, pp 215–221 | Cite as

Photoelastic-coating analysis in thermal fields

Objective of paper is to describe the realm of applicability of the photoelastic-coating method for problems involving temperature changes—with existing coating materials—and to prescribe methods for obtaining reliable results with these materials
  • F. Zandman
  • S. S. Redner
  • D. Post
Article

Abstract

If photoelastic-coating materials exhibited thermal conductivity and thermal expansion equal to that of structural materials, and if strain-optical sensitivity did not vary with temperature, photoelasticcoating analyses could be conducted in thermal fields exactly as in room-temperature test. Methods for circumventing problems associated with these material properties are presented.

Corrections are introduced as analytically and empirically derived factors to account for birefringence resulting from differential thermal expansion of coating and workpiece. Surface strains induced by external loading and by thermal stresses can be performed in the temperature range of −60° F to +350° F for tests of extended duration and to +500° F for brief periods.

Keywords

Thermal Conductivity Mechanical Engineer Material Property Thermal Expansion 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.

Notation

T

temperature

σ

stress

τ

shear stress

ε

strain

Φ

isoclinic parameter

E

modulus of elasticity

ν

Poisson’s ratio

N

photoelastic fringe order or birefringence

t

coating thickness

K

strain-optical coefficient

0

angle of incidence from normal to surface

β

pertaining to geometry of coating

Subscripts

x, y, z

acting along rectangular coordinate axes

1, 2, 3

acting along principal directions

u

pertaining to the region of uniform stress distribution

i, f

initial and final conditions

s, c

pertaining to workpiece and coating

α

associated with differential thermal expansion

0

pertaining to a straight boundary

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References

  1. 1.
    Gray, R. M., “Initial Fringes in Photoelastic Models and Their Effects,” (Purdue University),Proc. Soc. Exp. Stress Anal. 11 (1),115–118 (1953).Google Scholar
  2. 2.a)
    Zandman, F., and Maier, H. N., “Six New Techniques for Photoelastic Coatings, Prod. Eng. 42 (July 24, 1961).Google Scholar
  3. 2.b)
    Maier, H. N., “Stress Analysis as a Guide to Structural Design, Doehler Jarvis Research Bulletin #3, April 1961.Google Scholar
  4. 3.
    Zandman, F., and Redner, S., “Study of the Feasibility of Stress Analysis of Propellant Grains Using the PhotoStress Technique,” Budd Instruments Div. Test Report, April 1960. Test performed under Air Force Contract AF33(616)6530 for Thiokol Chemical Corp., Elkton, Md.Google Scholar

Copyright information

© Society for Experimental Mechanics, Inc. 1963

Authors and Affiliations

  • F. Zandman
    • 1
  • S. S. Redner
    • 2
  • D. Post
    • 3
  1. 1.Vishay Instruments, Inc.Malvern
  2. 2.Photolastic, Inc.Malvern
  3. 3.Vishay Instruments, Inc.Troy

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