Firstly, we propose the embedded-core capillary fiber structure for acting as a pressure sensor. Analytical and numerical studies were performed and showed that high pressure sensitivity could be achieved with this simplified fiber structure, which consists of a capillary structure with a germanium-doped core placed within the capillary wall.
By studying the fringe pattern one can determine the state of stress at various points in the material. For materials that do not show photoelastic behavior, it is still possible to study the stress distribution. The first step is to build a model, using photoelastic materials, which has geometry similar to the real structure under investigation.
The loading is then applied in the same way to ensure that the stress distribution in the model is similar to the stress in the real structure. Isoclinics and isochromatics[ edit ] Isoclinics are the loci of the points in the specimen along which the principal stresses are in the same direction.
Isochromatics are the loci of the points along which the difference in the first and second principal stress remains the same. Thus they are the lines which join the points with equal maximum shear stress magnitude.
However, examining photoelasticity in three-dimensional systems is more involved than two-dimensional or plane-stress system. So the present section deals with photoelasticity in a plane stress system. This condition is achieved when the thickness of the prototype is much smaller as compared to dimensions in the plane.
Thus one is only concerned with stresses acting parallel to the plane of the model, as other stress components are zero. The experimental setup varies from experiment to experiment. The two basic kinds of setup used are plane polariscope and circular polariscope.
The working principle of a two-dimensional experiment allows the measurement of retardation, which can be converted to the difference between the first and second principal stress and their orientation. To further get values of each stress component, a technique called stress-separation is required.
Plane polariscope setup[ edit ] The setup consists of two linear polarizers and a light source. The light source can either emit monochromatic light or white light depending upon the experiment.
First the light is passed through the first polarizer which converts the light into plane polarized light. The apparatus is set up in such a way that this plane polarized light then passes through the stressed specimen.
This light then follows, at each point of the specimen, the direction of principal stress at that point. The light is then made to pass through the analyzer and we finally get the fringe pattern.
The fringe pattern in a plane polariscope setup consists of both the isochromatics and the isoclinics. The isoclinics change with the orientation of the polariscope while there is no change in the isochromatics. Transmission Circular Polariscope The same device functions as a plane polariscope when quarter wave plates are taken aside or rotated so their axes parallel to polarization axes Circular polariscope setup[ edit ] In a circular polariscope setup two quarter- wave plates are added to the experimental setup of the plane polariscope.
The first quarter-wave plate is placed in between the polarizer and the specimen and the second quarter-wave plate is placed between the specimen and the analyzer.
The effect of adding the quarter-wave plate after the source-side polarizer is that we get circularly polarized light passing through the sample.
The analyzer-side quarter-wave plate converts the circular polarization state back to linear before the light passes through the analyzer. The basic advantage of a circular polariscope over a plane polariscope is that in a circular polariscope setup we only get the isochromatics and not the isoclinics.
This eliminates the problem of differentiating between the isoclinics and the isochromatics.While the stress response may warn us of immediate danger, like a fast-approaching car, prolonged stress can negatively affect your physical and emotional health.
*Brookman Technology, Inc., Japan the dark current reduces, and coincides with the result of Fig On the contrary, the positive bias such as the surface below the TG widely depleted, which causes a large surface generation. B. Optical Stress Fig. 5 shows the effect of optical stress on several driving conditions of TG, where Lo St, Hi.
Jul 12, · Deformed mesh in Stress-Optical Effects. Posted Jul 11, , AM PDT RF & Microwave Engineering, Mesh, Structural Mechanics & Thermal Stresses 1 Reply.
E. H. Send Private Message Report. Please login with a confirmed email address before reporting spam These days I am also working on the stress-optical effect.
But I met problems. Stress-Optical Effects with Generalized Plane Strain. Application ID: Planar photonic waveguides in silica (SiO2) have great potential for use in wavelength routing applications.
The major problem with this type of waveguide is birefringence. Anisotropic refractive indices result in fundamental mode splitting and pulse broadening.
The optical band gap and the ultraviolet emission peak of the films is found to shift to smaller values with the increase in the growth temperature, which shows a correlation in the optical band gap and the stress present in the film.
Photoelasticity describes changes in the optical properties of a material under mechanical deformation. It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material, where it gives a picture of stress distributions around discontinuities in materials.