Photoelastic-coating analysis in thermal fields

Dynamic Measurements with a Luminescent Photoelastic Coating

“…These are called isoclinic and isochromatic fringes. The isoclinic fringes indicate the principal stress directions and the isochromatic indicate the difference in principal stresses in the coating [7].…”

“…There are several methods that can be used to separate the principal strains and they include the lateralextensometer method, integration methods, mathematical solution of Laplace's equation, oblique incidence of light method [9], strip coatings [7], and thermoelasticity [10]. The lateralextensometer method is not applicable to photoelastic coatings [9] and the integration methods are only applicable to two-dimensional plane-stress problems [7]. The oblique incidence method is potentially the easiest full-field, 3D technique to employ in an experimental environment.…”

“…This wave can be modeled as a sinusoidal function where the amplitude of the light vector, , is a function of the position along the axis of propagation, , time, , speed of light propagation, , wavelength, , and maximum amplitude, [7]. Linear polarizers only allow the component of light parallel to the axis of polarization to pass through the plate [7]. This creates plane polarized light where all of the components of the light vector lie in the plane of polarization, and there is a reduction in light intensity ( Fig.…”

“…A retardation plate has the ability to split a light vector into two orthogonal components and, displays a retardation plate and the transmitted components [7]. Fig.…”

“…Fig. 2.5 Plane polarized light vector passing through a doubly refracting plate [7]. 13 The resulting components can be visualized as a phase shift between the two sinusoidal functions.…”