How does photoelastic stress analysis work?
In photoelastic stress analysis, a reflective coating is applied to the surface of the object under investigation, and a tool such as a digital polariscope splits coherent, monochromatic light into two beams and shines them on the object through a system of polarizers.
What is photoelastic effect?
The photoelastic effect (alternatively called the piezo-optical effect) is the change of refractive index caused by stress. Applications of photoelasticity involve applying a given stress state to a model and utilising the induced birefringence of the material to examine the stress distribution within the model.
What is photoelastic analysis?
Photoelastic stress analysis is a full-field technique for measuring the magnitudes and directions of principal stresses.
What is stress determination by photo elasticity?
Photoelasticity is a whole-field technique for measuring and visualizing stresses and strains in structures. The method utilizes a birefringent model of the actual structure to view the stress contours due to external loading or residual birefringence.
How does a photoelastic modulator work?
The photoelastic modulator (PEM) is a resonant polarization modulator. It operates at the resonant frequency of a desired mechanical vibration mode of its optical element. The PEM is made of isotropic optical materials, in contrast to the birefringent materials used in electro-optic modulators.
What is Fringe value?
In general, fringe benefits are valued at fair market value. This is the amount the employee would pay for the same benefit at retail.
What is photoelastic material?
A photoelastic material is one that has a stress dependent refractive index. When placed between crossed polarizers, the rotation of the polarized light by the stress field in the material generates a fringe pattern displaying contours of equal stress.
Why is photoelasticity important?
Photoelastic experiments (also informally referred to as photoelasticity) are an important tool for determining critical stress points in a material, and are used for determining stress concentration in irregular geometries.
What is the unit of material stress fringe value?
A quantity used in photoelastic work, equal to the stress which must be applied to a material, in pounds per square inch (1 pound per square inch equals approximately 6.89476 kilopascals), to produce a relative retardation of 1 wavelength between the components of a linearly polarized light beam when the light passes …
What is stress-optic law?
The Stress-Optic Law. This law established that birefringence is directly proportional to the difference of principal stresses, which is equal to the difference between the two indices of refraction, n1-n2, exhibited by a stressed material.
How does an AOM work?
An acousto-optic modulator (AOM) is a device which can be used for controlling the power of a laser beam with an electrical drive signal. A transducer generates a sound wave, at which a light beam is partially diffracted. The diffraction angle is exaggerated; it is normally only of the order of 1°.