Application of Holography to Photoelasticity

This paper discusses the exploratory application of holography to photoelasticity. It is shown that the two-beam holographic method may be used to record the birefringent pattern of a standard two-dimensional photoelastic specimen. A special type of polariscope is required. A discussion is presented of the various arrangements required to produce isochromatic, isoclinic, isopachic and combined isopachic and isochromatic fringe patterns. The three-dimensional nature of the holograph is utilized to separate the principal stresses by means of oblique incidence. Both normal- and oblique-incidence fringe patterns are recorded on a single hologram. A brief discussion of the extension to the dynamic case is presented.