... | @@ -23,8 +23,8 @@ where $`\lambda`$ is the wavelength of the light and $`d`$ is the distance trave |
... | @@ -23,8 +23,8 @@ where $`\lambda`$ is the wavelength of the light and $`d`$ is the distance trave |
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$`I=I_0 sin^2(\frac{\alpha}{2})=sin^2(\frac{\pi C d}{\lambda}(\sigma_1-\sigma_2)) `$
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$`I=I_0 sin^2(\frac{\alpha}{2})=sin^2(\frac{\pi C d}{\lambda}(\sigma_1-\sigma_2)) `$
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This equation relates internal stress and intensity for a single wavelength. In the experiment, both the light and camera channels cover a wide range of wavelengths.
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This equation relates internal stress and intensity for a single wavelength. In most of the cases, both the light and camera channels cover a wide range of wavelengths. Stress calculation is less noisy using narrow range of wavelength and single channel from the camera. However, it is still possible to retrieve stresses using white light.
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Stress calculation is less noisy using narrow range of wavelength and single channel from the camera. However, it is still possible to retrieve stresses using white light. In such as case, stress-optical relation can be evaluated using empirical calibration.
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The last equation makes it possible to invert the mechanical problem and to get the full stress field (even if there is non-uniqueness of the solution). This is not a trivial problem but in this wiki we show [how to do](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/inverse-analysis) it in the specific case of loaded discs. Other more [qualitative possibilities](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/method-analyze) exists to have an estimation of the stress field.
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[<go back to home](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/home) |
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[<go back to home](https://git-xen.lmgc.univ-montp2.fr/PhotoElasticity/Main/wikis/home) |
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