US3847481A
Expired / Lapsed
US
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Photoelastic processes for examining mechanical stresses
Assignee: Centre Technique des Industries Mécaniques
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Filing: 1973-03-29
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Granted: 1974-11-12
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Expires: 1993-03-29
Abstract
Abstract A process of visualizing the maximum-shear lines or isostatics by observations under polarized light of the double refractions appearing in a photoelastic material comprises obtaining by means of a noval polariscope device moire images by observing simultaneously the material and a grid for the isostatics for different successive orientations of the plane of polarization. The successive orientations are obtained by simultaneously rotating the plane of the polarized light and the grid. One at least of the material and the grid is observed in the form of an optical image formed in the plane of the other.
Inventors
- 👤 D Paraskevas
- 👤 Hermite A L
- 👤 G Bernard
- 👤 J Guinet
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:56
CPC Classifications
G; G01; G01L; G01L1/00; G01L1/24; G01L1/241; G01B; G01B11/00; G01B11/16; G01B11/18
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
117 words
A device for use in vIsualization of mechanical stress lines by observation, under a polarized light source, of the double refraction images from a photoelastic material comprising: means defining an optical path between a light source, a photoelastic material to be observed and a screen for receiving the images from said material, a polarizer and an analyzer respectively arranged in the optical path between the source and the material, and the material and the screen, a grid distant from the material and superimposed on said screen, and means for synchronized rotation of the polarizer, the analyzer and the grid relative to the optical path axis to produce a succession of said images at different angular orientations thereof.
Claim 2
Independent Claim
117 words
A device for use in vIsualization of mechanical stress lines by observation, under a polarized light source, of the double refraction images from a photoelastic material comprising: means defining an optical path between a light source, a photoelastic material to be observed and a screen for receiving the images from said material, a polarizer and an analyzer respectively arranged in the optical path between the source and the material, and the material and the screen, a grid distant from the material and superimposed on said screen, and means for synchronized rotation of the polarizer, the analyzer and the grid relative to the optical path axis to produce a succession of said images at different angular orientations thereof.
Claim 3
Dependent Claim
18 words
A device as claimed in claim 1, wherein the grid is arranged between the source and the polarizer.
Claim 4
Dependent Claim
24 words
A device as claimed in claim 2, wherein the grid is mounted on a support which is linearly adjustable along the optical path axis.
Claim 5
Dependent Claim
27 words
A device as claimed in claim 1, wherein the polarizer and the grid are mounted on a common support, which is rotatable about the optical path axis.
Claim 6
Dependent Claim
17 words
A device as claimed in claim 4, wherein the screen is also integral with the said support.
Claim 7
Dependent Claim
13 words
A device as claimed in claim 1 wherein said light source is stroboscopic.
Claim 8
Dependent Claim
13 words
A device as claimed in claim 1, wherein said light source is stroboscopic.
Claim 9
Independent Claim
120 words
A device for use in visualization of mechanical stress lines by observation, under a polarized light source, of the double refraction images from a photoelastic material comprising: means defining an optical path between a light source, a photoelastic material to be observed and a screen for receiving the images from said material, a polarizer and an analyzer respectively arranged in the optical path between the source and the material, and the material and the screen, a grid distant from the material and associated with means for forming an optical image, and means for synchronized rotation of the polarizer, the analyzer and the grid relative to the optical path axis to produce a succession of images at different angular orientations thereof.
Claim 10
Independent Claim
120 words
A device for use in visualization of mechanical stress lines by observation, under a polarized light source, of the double refraction images from a photoelastic material comprising: means defining an optical path between a light source, a photoelastic material to be observed and a screen for receiving the images from said material, a polarizer and an analyzer respectively arranged in the optical path between the source and the material, and the material and the screen, a grid distant from the material and associated with means for forming an optical image, and means for synchronized rotation of the polarizer, the analyzer and the grid relative to the optical path axis to produce a succession of images at different angular orientations thereof.
Claim 11
Dependent Claim
18 words
A device as claimed in claim 8, wherein the grid is arranged between the source and the polarizer.
Claim 12
Dependent Claim
24 words
A device as claimed in claim 9, wherein the grid is mounted on a support which is linearly adjustable along the optical path axis.
Claim 13
Dependent Claim
27 words
A device as claimed in claim 8, wherein the polarizer and the grid are mounted on a common support, which is rotatable about the optical path axis.
Claim 14
Dependent Claim
18 words
A device as claimed in claim 11, wherein the screen is also integral with the said common support.
Claim 15
Independent Claim
100 words
A device for directly visualizing the mechanical stress lines caused by observing, under polarized light, the double refractions appearing in a photoelastic material, said device comprising: means for producing a moire image by simultaneously observing the material and a grid having lines oriented at a predetermined angle to the plane of light polarization for obtaining mechanical stress lines; means for rotating said grid and the light polarization plane to obtain moire images from a plurality of angular orientations thereof; means for receiving said moire images, whereby superimposing all the moire images thereon produces said direct visualization of the mechanical stress.
Claim 16
Independent Claim
100 words
A device for directly visualizing the mechanical stress lines caused by observing, under polarized light, the double refractions appearing in a photoelastic material, said device comprising: means for producing a moire image by simultaneously observing the material and a grid having lines oriented at a predetermined angle to the plane of light polarization for obtaining mechanical stress lines; means for rotating said grid and the light polarization plane to obtain moire images from a plurality of angular orientations thereof; means for receiving said moire images, whereby superimposing all the moire images thereon produces said direct visualization of the mechanical stress.
Claim 17
Independent Claim
127 words
A method of directly visualizing on an image receiving device the mechanical stress lines caused by observing, under polarized light, the double refractions appearing in a photoelastic material, said method comprising: a. producing a moire image by simultaneously observing the material and a grid having lines oriented at a predetermined angle to the plane of light polarization for obtaining mechanical stress lines, one of said grid and said material being observed as an optical image formed in the plane of the other; b. rotating said grid and the light polarization plane to a new angular position; c. producing a subsequent moire imagE at said new angular position; d. superimposing said subsequent image on all prior moire images; e. repeating steps (b), (c) and (d) at least once.
Claim 18
Independent Claim
127 words
A method of directly visualizing on an image receiving device the mechanical stress lines caused by observing, under polarized light, the double refractions appearing in a photoelastic material, said method comprising: a. producing a moire image by simultaneously observing the material and a grid having lines oriented at a predetermined angle to the plane of light polarization for obtaining mechanical stress lines, one of said grid and said material being observed as an optical image formed in the plane of the other; b. rotating said grid and the light polarization plane to a new angular position; c. producing a subsequent moire imagE at said new angular position; d. superimposing said subsequent image on all prior moire images; e. repeating steps (b), (c) and (d) at least once.
Claim 19
Dependent Claim
46 words
A method according to claim 14 wherein the step of producing a moire image includes the sub-step of reflecting the polarized light from a reflective layer subjacent said photoelastic material, a real optical image of said grid being formed in the plane of said reflective layer.
Claim 20
Dependent Claim
16 words
A method according to claim 14 including forming the successive moire images on an observation screen.
Claim 21
Dependent Claim
39 words
The method of claim 14 wherein the step of rotating the grid and the plane of polarization to a new position and the step of producing a subsequent moire'' image are accomplished at a rate exceeding human retinal analysis.
Claim 22
Dependent Claim
28 words
The method according to claim 16 wherein the step of rotating is continuous and the step of producing subsequent moire'' images is accomplished by strobing the light source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-11 | 1978-05-13 | 1978-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-11 | 1982-05-13 | 1982-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-11 | 1986-05-13 | 1986-11-12 | $7700.00 | Window Closed / Lapsed |