US3603142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting cracks and measuring strain in polymeric structures
Assignee: ARCH D JOHNSTON
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Filing: 1970-05-07
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Granted: 1971-09-07
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Expires: 1990-05-07
Abstract
Abstract Strips of conductor-filled polymer are applied to the surface of polymeric structures in which it is desired to detect cracks and the conductivity of the applied strips is monitored. If a crack develops in the underlying polymeric structure and propagates itself through an applied strip, the strip will lose its ability to conduct electricity and the crack will be detected. By measuring the resistance of the strips, strain in the polymeric structure can also be determined. The invention is particularly useful in detecting cracks and strain in solid rocket propellant grains.
Inventors
- 👤 Donald Saylak
- 👤 Arch D Johnston
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:04
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/20; G01N27/205
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
22 words
The method of claim 1 wherein said conductive material is selected from the group consisting of particles of silver, copper, and gold.
Claim 2
Dependent Claim
23 words
The method of claim 1 wherein said filled polymer has a composition which is substantially the same as that of said polymeric structure.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein said polymeric structure has solid materials incorporated therein.
Claim 4
Dependent Claim
31 words
The method of claim 4 wherein the amount of said conductive material utilized is sufficient to give said filled polymer physical properties which are similar to those of said polymeric structure.
References Cited (Backward Citations)
GB939282A
Cited
GB720602A
Cited
US2986928A
Cited
US3080748A
Cited
US3289135A
Cited
US3205464A
Cited
US3509942A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-06 | 1975-03-08 | 1975-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-06 | 1979-03-08 | 1979-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-06 | 1983-03-08 | 1983-09-07 | $7700.00 | Window Closed / Lapsed |