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US4164874A
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Flaw growth correlator
Assignee: Boeing Wichita Co
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Filing: 1978-01-19
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Granted: 1979-08-21
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Expires: 1998-01-19
Abstract
Abstract A flaw growth correlator for monitoring flaw growth potential in a structural body. The correlator providing a major increase in the sensitivity of flaw growth when compared to current designs of constant thickness crack gauges.
Inventors
- 👤 Gary G. Cassatt
- 👤 Richard J. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:50
CPC Classifications
G; G01; G01N; G01N3/00; G01N3/02; G01N3/06; G01B; G01B3/00; G01N2203/00; G01N2203/0058; G01N2203/006; G01N2203/0062; G01N2203/02; G01N2203/06; G01N2203/067; G01N2203/0682
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
119 words
A flaw growth correlator for monitoring flaw growth potential in a structural body, the correlator comprising: a flat metal gauge having a top, a bottom, sides, a first end portion, a second end portion, and a center portion, said gauge having a length (L), a width (W), and a thickness (T), the center portion including a necked down area across the width (W) of said gauge and having a thickness (X) less than (T); and a crack initiating stress raiser disposed in the necked down area of the center portion of said gauge; an aperture in the necked down area of the center portion of said gauge, said crack-initiating stress raiser extending outwardly from the side of said aperture.
Claim 2
Dependent Claim
119 words
A flaw growth correlator for monitoring flaw growth potential in a structural body, the correlator comprising: a flat metal gauge having a top, a bottom, sides, a first end portion, a second end portion, and a center portion, said gauge having a length (L), a width (W), and a thickness (T), the center portion including a necked down area across the width (W) of said gauge and having a thickness (X) less than (T); and a crack initiating stress raiser disposed in the necked down area of the center portion of said gauge; an aperture in the necked down area of the center portion of said gauge, said crack-initiating stress raiser extending outwardly from the side of said aperture.
Claim 3
Dependent Claim
23 words
The correlator as described in claim 1 wherein said crack-initiating stress raiser is in the side of the center portion of said gauge.
Claim 4
Dependent Claim
29 words
The correlator as described in claim 1 wherein said crack-initiating stress raiser is disposed in the center of the necked down area of the center portion of said gauge.
Claim 5
Dependent Claim
22 words
The correlator as described in claim 1 further including a second crack-initiating stress raiser extending outwardly from the side of said aperture.
Claim 6
Dependent Claim
30 words
The correlator as described in claim 1 further including means for measuring the length of the crack growth on the top of said gauge and parallel to said stress raiser.
Claim 7
Dependent Claim
33 words
The correlator as described in claim 1 further including securing means applied to the bottom of the first and second end portions for securing said gauge to the top of the structural body.
Claim 8
Dependent Claim
15 words
The correlator as described in claim 6 wherein said securing means is a bonding agent.
Claim 9
Dependent Claim
28 words
The correlator as described in claim 7 wherein the bottom of the first and second end portions of said gauge is tapered for relieving severity of bonding discontinuity.
Claim 10
Dependent Claim
18 words
The correlator as described in claim 6 wherein said securing means is a rivet, bolt, or the like.
Claim 11
Dependent Claim
32 words
The correlator as described in claim 1 wherein the thickness (X) of the necked down area of the center portion of said gauge is in a range of 0.01 to 0.08 inches.
Claim 12
Dependent Claim
23 words
The correlator as described in claim 1 wherein the thickness (T) of said gauge is in a range of 0.08 to 0.25 inches.
Claim 13
Dependent Claim
26 words
The correlator as described in claim 1 wherein the necked down area of the center portion of said gauge is in the top of said gauge.
Claim 14
Dependent Claim
30 words
The correlator as described in claim 1 wherein the necked down area in the center portion of said gauge is in both the bottom and the top of said gauge.
Claim 15
Dependent Claim
19 words
The correlator as described in claim 1 wherein said stress raiser is a cut slit, notch, or the like.
Claim 16
Dependent Claim
173 words
A flaw growth correlator for monitoring flaw growth potential in a structural body, the correlator comprising: a flat angular shaped metal gauge having a top, a bottom, sides, a first end portion, a second end portion, and a center portion, said gauge having a length (L), a width (W), and a thickness (T), the thickness (T) in a range of 0.08 to 0.25 inches, the center portion of said gauge including a necked down area across the width (W) of said gauge and having a thickness (X) less than (T), the thickness (X) in a range of 0.01 to 0.08 inches; a crack-initiating stress raiser disposed in the necked down area of the center portion of said gauge and parallel to the width (W) of said gauge; means for measuring the length of the crack growth on the top of said gauge and parallel to said stress raiser; and securing means applied to the bottom of the first and second end portions for securing said gauge to the surface of the structural body.
Claim 17
Dependent Claim
173 words
A flaw growth correlator for monitoring flaw growth potential in a structural body, the correlator comprising: a flat angular shaped metal gauge having a top, a bottom, sides, a first end portion, a second end portion, and a center portion, said gauge having a length (L), a width (W), and a thickness (T), the thickness (T) in a range of 0.08 to 0.25 inches, the center portion of said gauge including a necked down area across the width (W) of said gauge and having a thickness (X) less than (T), the thickness (X) in a range of 0.01 to 0.08 inches; a crack-initiating stress raiser disposed in the necked down area of the center portion of said gauge and parallel to the width (W) of said gauge; means for measuring the length of the crack growth on the top of said gauge and parallel to said stress raiser; and securing means applied to the bottom of the first and second end portions for securing said gauge to the surface of the structural body.
References Cited (Backward Citations)
US2920480A
Cited
US3136154A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-08-20 | 1983-02-19 | 1983-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-20 | 1987-02-19 | 1987-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-20 | 1991-02-19 | 1991-08-21 | $7700.00 | Window Closed / Lapsed |