Abstract
In photoelastic stress analysis, a need sometimes exists for a birefringent material in which the experimenter has the ability to vary its mechanical or elastic properties. It was the intent of this investigation to produce a homogeneous, isotropic solid with variable mechanical properties and which was suitable for photoelastic use.
This goal is accomplished through the fabrication of a discontinuous composite where the birefringent constitutents have matched indices of refraction in the unstressed state. The constituents of this composite are solid-glass microspheres embedded in a polyester matrix.
Three theories are formulated to define the stress-induced birefringent phenomena found in composites of this nature. Conventional photoelastic techniques were employed to produce data appropriate for comparison to the predictions of these theories.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- f c :
-
material fringe constant of composite
- f g :
-
material fringe constant of glass inclusion
- f m :
-
material fringe constant of matrix material
- E c :
-
elastic modulus of composite
- E g :
-
elastic modulus of glass inclusion
- E m :
-
elastic modulus of matrix material
- N c :
-
total retardation of wavefront traversing composite
- N g :
-
total retardation of wavefront traversing glass inclusions
- N m :
-
total retardation of wavefront traversing matrix material
- P x :
-
applied load in x-coordinate direction
- t c :
-
composite thickness in direction of light propagation
- t g :
-
most-probable path length of light in glass inclusion
- t m :
-
most-probable path length of light in matrix material
- V fg :
-
volume fraction of glass inclusions
- V fm :
-
volume fraction of matrix material
- v c :
-
Poisson's ratio of composite
- v g :
-
Poisson's ratio of glass inclusions
- v m :
-
Poisson's ratio of matrix material
- ɛ xc :
-
average strain in composite in x-coordinate direction
- ɛ xg :
-
average strain in glass inclusion in x-coordinate direction
- ɛ xm :
-
average strain in matrix material in x-coordinate direction
- σ xc :
-
average stress in composite in x-coordinate direction
- σ xg :
-
average stress in glass inclusion in x-coordinate direction
- σ xm :
-
average stress in matrix material in x-coordinate direction
- σ1 :
-
maximum principal stress
- σ2 :
-
minimum principal stress
References
“Potters Technical Quality Glass Beads for Industrial and Scientific Applications,” Potters Industries, Inc., Carlstadt, N. J.
Dally, J. R. andPrabhakaran, R., Photo-orthotropic-elasticity,Experimental Mechanics,11 (8),346–356 (Aug.1971).
Hill, R., “Elastic Properties of Reinforced Solids; Some Theoretical Principles,”J. of Mech. and Phys. of Solids,11,357–372 (1963).
Hill, R., “Self-Consistent, Mechanics of Composite Materials,”J. of Mech. and Phys. of Solids,13,213–222 (1965).
Richard, T. G., “The Mechanical and Optical Characterization of a Microsphere Filled Composite,”PhD Thesis, University of Wisconsin, Madison, WI (1973).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Richard, T.G., Young, W.C. The birefringent response of a potential photoelastic material with variable elastic properties. Experimental Mechanics 15, 226–229 (1975). https://doi.org/10.1007/BF02319427
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF02319427