Abstract
This paper presents a new method for whole-field stress analysis based on a symbiosis of two techniques—classical photoelasticity and modern digital image analysis. The resulting method is called ‘half-fringe photoelasticity (HFP)’.
Classical photoelasticity demands materials with high birefringence, which leads to extensive use of plastics as model materials. Since the behavior of these materials is often different from that of the prototype materials, their use distorts the similitude relationships. In many contemporary problems this distortion is untenable. HFP offers a way out of this dilemma. It permits materials and loads to be chosen so that no more than one half of a fringe order appears in the area of interest. Thus, for example, glass, which behaves linearly up to high stress levels and over a wide range of temperatures, could be used as model material. Alternatively, models from polymeric materials could be used under very low load in order to stay within the linear part of the stress-strain diagram and to prevent large deformations. The half-fringe-photoelasticity system, which is described here, utilizes the resulting low levels of birefringence for effective stress analysis.
This paper describes the system. It outlines a calibration routine and illustrates its application to two simple problems using glass models.
Article PDF
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.Avoid common mistakes on your manuscript.
Abbreviations
- A :
-
constant
- C :
-
stress-optic coefficient
- c :
-
the relative stress-optic coefficient
- f σ :
-
material fringe value
- h :
-
thickness of the specimen in the direction of light propagation
- I :
-
image brightness
- K :
-
constant
- N :
-
relative retardation in terms of complete cycles (fringe order)
- Z :
-
digital-output value
- γ:
-
slope of the scanner sensitivity curve
- Δ:
-
relative retardation in radians
- λ:
-
wavelength of the light
- \(\sigma _i \) :
-
in-plane principal stresses
- ψ:
-
constant
References
Zandman, F., “Photostress Analysis,”Product Engineering,30 (9),43–46 (March 2,1959).
Redner, S., “New Automatic Polariscope System,”Experimental Mechanics 14 (12),486–491 (1974).
Mueller, R.K. andSaackel, L., “Complete Automatic Analysis of Photoelastic fringes,”Experimental Mechanics,19 (7),245–251 (1979).
Burger, C.P. andVoloshin, A.S., “Half-fringe Photoelasticity: A New Instrument for Whole Field Stress Analysis,”ISA Transactions,22 (2),85–95 (1983).
Kuske, A., Robertson, G., Photoelastic Stress Analysis, John Wiley and Sons, London, 100–102 and 112 (1974).
Frocht, M.N., Photoelasticity, John Wiley and Sons, New York,2,238 (1948).
Voloshin, A.S. and Burger, C.P., “Photo-Orthotropic Elasticity Through a Digital Image Analysis of Low Level Bi-refringence,” Proc. 7th Inter. Conf. on Exper. Stress Anal., Haifa, Israel, 483–494 (1982).
Miskioglu, I., Voloshin, A.S., and Burger, C.P., “Evaluation of Stress Intensity Factors Using Half-Fringe Photoelasticity,” Abstracts 19th Annual Meeting Soc. of Eng. Sci., Rolla, MO, 100 (1982).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Voloshin, A.S., Burger, C.P. Half-fringe photoelasticity: A new approach to whole-field stress analysis. Experimental Mechanics 23, 304–313 (1983). https://doi.org/10.1007/BF02319257
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02319257