Method for determining properties of optically isotropic and anisotropic materials

A method for optically determining the ratio of Poisson's ratio to modulus of elasticity for optically isotropic and optically anisotropic transparent materials and then for determining the stress-optical constants for such materials. A collimated monochromatic light beam is directed at the tip of a crack in a loaded thin plate specimen of the material and the diameters of the resulting transmitted and reflected caustics are measured at points equidistant from the specimen. The light beam also is directed to an uncracked region in a loaded thin plate specimen of the material and the number of displaced fringe reflected on a screen are counted for a predetermined change in loading. The ratio of Poisson's ratio to modulus of elasticity and the stress-optical constants are determined from the thickness of the specimen, the displaced fringe count, the wavelength of the light beam and the ratio of the caustic diameters.
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Abstract/Description: A method for optically determining the ratio of Poisson's ratio to modulus of elasticity for optically isotropic and optically anisotropic transparent materials and then for determining the stress-optical constants for such materials. A collimated monochromatic light beam is directed at the tip of a crack in a loaded thin plate specimen of the material and the diameters of the resulting transmitted and reflected caustics are measured at points equidistant from the specimen. The light beam also is directed to an uncracked region in a loaded thin plate specimen of the material and the number of displaced fringe reflected on a screen are counted for a predetermined change in loading. The ratio of Poisson's ratio to modulus of elasticity and the stress-optical constants are determined from the thickness of the specimen, the displaced fringe count, the wavelength of the light beam and the ratio of the caustic diameters.
Subject(s): 356/32
73/800
Date Issued: 1980-04-01
Title: Method for determining properties of optically isotropic and anisotropic materials.
Name(s): The University of Toledo, assignee
Raftopoulos, Demetrios D., inventor
Kartalopoulos, Stamatios V., inventor
Type of Resource: text
Genre: patent
Publisher: United States Patent and Trademark Office
Other Date: Date Filed: 1978-10-03
Date Issued: 1980-04-01
Physical Form: application/pdf
Extent: 10 p.
Abstract/Description: A method for optically determining the ratio of Poisson's ratio to modulus of elasticity for optically isotropic and optically anisotropic transparent materials and then for determining the stress-optical constants for such materials. A collimated monochromatic light beam is directed at the tip of a crack in a loaded thin plate specimen of the material and the diameters of the resulting transmitted and reflected caustics are measured at points equidistant from the specimen. The light beam also is directed to an uncracked region in a loaded thin plate specimen of the material and the number of displaced fringe reflected on a screen are counted for a predetermined change in loading. The ratio of Poisson's ratio to modulus of elasticity and the stress-optical constants are determined from the thickness of the specimen, the displaced fringe count, the wavelength of the light beam and the ratio of the caustic diameters.
Identifier(s): utpatents-US4195929 (IID)
Patent No.: US4195929 (patno)
Appl. No.: 05/948317 (appno)
Subject(s): 356/32
73/800
Held by: United States Patent and Trademark Office (USPTO) Public Search Facility
Location: University of Toledo Digital Repository
Rights Statement: No Copyright - United States
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