What is Photoelasticity?
Photoelasticity is the best testing method that helps to determine the smoothness of material distribution and its equality throughout the bottle where it becomes unmanageable to understand the mathematical techniques. This testing technique is completely different from the analytical methods to calculate stress distribution in the quality of the material. This procedure offers highly precise results to measure the particular level of stress even under unexpected continuities in the material. It is the best testing machine which is used to measure the critical point of stress in a material and is usually used to measure the factor of stress concentration in an asymmetrical geometry.
Working Strategy of Photoelasticity
The strategy of photoelasticity works on the property of birefringence, which is analyzed by a transparent material. It is the property where a ray of light passes through the material and express two refractive indices. The property of double refraction is diverted with the optical crystals. In the case of photoelastic materials, it displays the property of birefringence only on the magnitude of refractive indices and on the application of stress at each point of the material that replicates the state of stress at that particular point.
When two rays of lights go from the photoelastic material, it quickly becomes polarized and provides two directions of stress and each of the stress experience different refractive indices. The change in the refractive index directly replicates the relative phase difference in the waves of two components which is known as phase retardation. Therefore, the application of photoelasticity of two-dimensional planes is much easier to analyze mainly when the thickness of the photoelasticity is small as compared to that of dimensions of the planes. The results of the testing procedures vary on the basis of different products. But the two main kinds of set up which are required to perform the test procedure are Plane Polariscope and Circular Polariscope.
A polariscope is the best testing instrument which is used to evaluate the stress distribution of PET and Preforms to measure the strength and quality of the products. A slight change in the stress/material distribution indicates the change in the refractive index of the material which shows the lower strength of the product. With the help of the polariscope, the defects can be analyzed and rectified easily and efficiently.