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.
KeywordsDrilling Alcos Hines
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