Working Principle of Photoelasticity

FARIDABAD, India - July 10, 2015 - PRLog -- Photoelasticity is an experimental test method that explains the stress distribution in materials like glass and PET Bottles where mathematical procedures become relatively awkward. Dissimilar from the analytical methods of stress distribution, photoelasticity provides a comparatively accurate picture of stress distribution even in sudden discontinuities in a material. The procedure serves as an important tool to determine the significant stress points of a material like glass, Pet & Preforms and is frequently used to analyze the stress concentration features in irregular mathematics.

The test procedure is based on the property of birefringence which is demonstrated by some transparent materials. Birefringence is that property which passes a ray of light through a material which experience two refractive indexes. The property of double refraction or birefringence is demonstrated by many optical crystals. But photoelastic materials explain the property of birefringence only through the application of stress and the magnitude of the refractive indexes at every point of the products which is directly related to the condition of stress at that particular point.

When a beam passes through a photoelastic product i.e. a glass or PET bottles, it becomes polarized and get resolute along the two main principal stress directions, and each of this mechanism experiences the different refractive indexes. The difference shown in the refractive index will lead to a relative phase difference which shows clearly between the two component influences which are generally called phase retardation. The degree of the relative retardation is elucidated clearly with the optic stress law.

Photoelasticity of a material can be explained by two and three-dimensional condition of stress. Though, the purpose of photoelasticity to the two-dimensional plane stress method is much easier to examine especially when the thickness of the specimen is comparatively smaller than the dimensions in the plane. In such cases, the only stress distributions that perform in the plane of the solid, as compared to other stress components are zero. The experimental setup varies from an experimental setup that varies from one experiment to another, but the two basic kinds of set up used are circular and plane polariscope.

Principles of Photoelasticity

When a light passes through a homogeneous isotropic media like glass, PET Bottles, it describes the refraction of incoming light.

The photoelasticity of a material can be detected easily with the help of testing instrument known as Polariscope. It is the best testing machine that helps to determine the strain distribution and the refractive index of the materials. For more information visit- http://www.testing-instruments.com/polariscope/