What is photoelastic stress analysis?
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.
What is the job of the polarizer in the photoelasticity 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.
How does a quarter wave plate work?
Quarter-Waveplates. Quarter-waveplates are used to turn linearly polarized light into circularly polarized light and vice versa. To do this, the waveplate must be oriented so that equal amounts of fast and slow waves are excited.
What is half wave plate explain?
: a crystal plate that reduces by ¹/₂ cycle the phase difference between the two components of polarized light traversing it — compare quarter-wave plate.
In recent years, photoelastic stress analysis has become a technique of outstanding importance to engineers. When polarised light is passed through a stressed transparent model, interference patterns or fringes are formed.
What are the advantages of photoelastic inspection?
Photoelastic inspection will allow detection of frozen-in strains, allowing identification of failure, with the method revealing the actual levels of orientation in the part. Some transparent plastics such as polycarbonate are highly birefringent and lend themselves to photoelastic stress analysis.
How do you determine the state of stress at various points?
By studying the fringe pattern of polarized light, one can determine (visualize) the state of stress at various points in the material [286,287]. Photoelastic stress analysis was introduced into dentistry to evaluate different types orthodontic movements [288].
How to visualize critical stress points using fringe pattern?
It helps to visualize critical stress points using a photoelastic, homogeneous, isotropic material. By studying the fringe pattern of polarized light, one can determine (visualize) the state of stress at various points in the material [286,287].