Method for detecting stress and strain
First Claim
1. A method for detecting stress and strain, the method comprising:
- a. providing a part coated with a photoelastic layer comprising non-opaque powder coat that becomes optically anisotropic when subjected to stress and strain;
b. detecting stress and strain in said part using the photoelastic properties of said photoelastic layer.
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Abstract
A method of detecting stress and strain using a powder coat finish and photoelastic techniques. A part is provided with a photoelastic layer comprising a non-opaque powder coat finish that becomes optically anisotropic when stressed. Photoelastic techniques are used to detect and measure stress and strain in the part. Fringe patterns appear in the photoelastic layer indicating the locations and magnitudes of the stress and strain when the part is illuminated with polarized light and viewed through a polarizing filter. Stress and strain resulting from applied forces are detected. Structural deformation in parts that have experienced plastic deformation is also detected. Photoelastic techniques using powder coat as a photoelastic technique are less expensive and easier to apply than traditional photoelastic coatings. Applications include testing of prototypes, stress testing, inspection and monitoring of production parts, and anywhere that viewing and measuring of stress and strain are of interest.
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Citations
30 Claims
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1. A method for detecting stress and strain, the method comprising:
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a. providing a part coated with a photoelastic layer comprising non-opaque powder coat that becomes optically anisotropic when subjected to stress and strain;
b. detecting stress and strain in said part using the photoelastic properties of said photoelastic layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
a. illuminating said part with polarized light;
b. viewing the light reflected from said part through a polarizing filter to determine if fringe patterns are visible in said photoelastic layer.
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13. The method according to claim 12, wherein said part is illuminated with circularly polarized light.
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14. The method according to claim 12, wherein the step of viewing the reflected light comprises viewing the reflected light through a quarter-wave plate.
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15. The method according to claim 12, wherein the step of viewing the reflected light comprises recording the reflected light with a camera.
- 16. A method for performing photoelastic analysis on a part comprising applying a photoelastic layer as a dry, finely divided solid and curing the solid powder to form a continuous film which adheres to said part, whereby stress and strain in said part can be detected.
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24. A method for detecting plastic deformation, the method comprising:
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a. providing a part coated with a photoelastic layer of non-opaque powder coat that becomes optically anisotropic when subjected to stress and strain;
b. applying a load to said part;
c. illuminating said part with a source of polarized light;
d. viewing the light reflected from said part through a polarizer after removal of said load;
whereby the presence of fringe patterns in said photoelastic layer indicates that plastic deformation of said part has occurred. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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Specification