US3911734A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detecting incipient fatigue damage in metal
Assignee: ConocoPhillips Co
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Filing: 1974-01-04
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Granted: 1975-10-14
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Expires: 1994-01-04
Abstract
Abstract A method of detecting incipient fatigue damage in a metal specimen by periodic proof tests wherein the metal specimen is removed from service, subjected to a load and the acoustic emission characteristics determined during application of the load.
Inventors
- 👤 Parviz Mehdizadeh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 21:36
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
118 words
A method of detecting incipient fatigue damage in a metal specimen subjected to repeated fatigue life cycles during the service of said metal specimen comprising: a. removing the metal specimen from service; b. applying a tension load to the specimen at least equal to the load the specimen receives in service; c. determining the total number of acoustic emissions produced during said loading; d. removing the tension load from the specimen and returning the specimen to service; e. repeating steps (a) through (d) until a plot of acoustic emissions versus fatigue life cycles indicates incipient fatigue damage in the specimen; and f. permanently removing the specimen from service prior to the development of a detectable fatigue crack therein.
Claim 2
Independent Claim
118 words
A method of detecting incipient fatigue damage in a metal specimen subjected to repeated fatigue life cycles during the service of said metal specimen comprising: a. removing the metal specimen from service; b. applying a tension load to the specimen at least equal to the load the specimen receives in service; c. determining the total number of acoustic emissions produced during said loading; d. removing the tension load from the specimen and returning the specimen to service; e. repeating steps (a) through (d) until a plot of acoustic emissions versus fatigue life cycles indicates incipient fatigue damage in the specimen; and f. permanently removing the specimen from service prior to the development of a detectable fatigue crack therein.
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) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |