Photoelastic Techniques for the Complete Determination of Stresses in Composite Structures
Transmission photoelastic analysis of composite models has attracted increasing attention in recent years. The interpretation of the photoelastic response in terms of the average (macroscopic) composite stresses is more involved than for isotropic models. Methods of determining the individual principal stresses (or strains) which have been suggested so far are not satisfactory. In this paper, three new methods are examined. The first method is an extension of the oblique incidence technique in which the model (or the light beam) is rotated about one of the material symmetry axes. In the second method, transmission and reflection photoelastic responses are combined. The third method requires the drilling of small holes and the determination of the fringe orders at selected points on the hole boundary. The three methods are applied to an orthotropic circular disk under diametral compression. Results are compared with strain gage data.
KeywordsPrincipal Stress Fringe Pattern Oblique Incidence Fringe Order Hole Boundary
Unable to display preview. Download preview PDF.
- 1.Prabhakaran, R., Developments in photo-orthotropic-elasticity, International Union of Theoretical and Applied Mechanics Symposium on Optical Methods in Solid Mechanics, Poitiers, France, Sept. 1979.Google Scholar
- 2.Prabhakaran, R., Applications of transmission photoelasticity to composite materials. In: Developments in composite materials, Vol. 2, Holister, G. S. (ed.), Barking, England, Applied Science Publishers, in press.Google Scholar
- 4.Tesar, V., La Photoelasticimetrie et ses applications dans les constructions aeronautiques, La Science Aerienne, Paris (1932).Google Scholar
- 5.Durelli, A. J. and Murray, W. M., Stress distribution around a circular discontinuity in any two-dimensional system of combined stress, 14th Semiannual Eastern Photoelasticity Conference, Yale Univ., 1941.Google Scholar
- 6.Prabhakaran, R., Extension of the hole-drilling method to birefringent composites, 36th Annual Conference of the Society of the Plastics Industry, Washington, DC, Feb. 1981.Google Scholar
- 7.Prabhakaran, R., Extension of oblique incidence method to photo-orthotropic elasticity, presented at the Spring Meeting of the Society for Experimental Stress Analysis, Dearborn, Michigan, USA, May 1981.Google Scholar