US4255478A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Composite structures
Assignee: United States Department of the Air Force
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Filing: 1979-03-14
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Granted: 1981-03-10
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Expires: 1999-03-14
Abstract
Abstract A composite structure is fabricated from fiber-reinforced tape, segments of the tape being stacked one upon another so as to form a plurality of plies. A boron fiber is positioned adjacent to or along an edge of each of the tape segments. Because of the X-ray opacity of the boron fiber's tungsten boride core and because the boron fiber will break when a ply is damaged, damage to the composite structure can be detected by radiographic examination.
Inventors
- 👤 Robert L. Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 08:34
CPC Classifications
B; B29; B29C; B29C70/00; B29C70/04; B29C70/28; B29C70/54; B29C70/06; B29C70/08; B29C70/083; B29C70/10; B29C70/16; B29C70/22; B29C70/228; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B29C37/00; B29C2037/90; B32B2262/00; B32B2262/10; B32B2262/103; B32B2305/00; B32B2305/08; Y; Y10; Y10S; Y10S428/00; Y10S428/902; Y10T; Y10T428/00; Y10T428/24; Y10T428/24058; Y10T428/24074; Y10T428/24091; Y10T428/24099; Y10T428/24116; Y10T428/24124; Y10T428/24132
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
90 words
A composite structure comprising a resin tape reinforced with fibers other than boron fibers having a tungsten boride core, the reinforcing fibers being parallel to edges of the tape, and segments of the tape being stacked one upon another so as to form a plurality of plies; and a boron fiber having a tungsten boride core positioned along an edge of each tape segment and having a length about equal to the length of the edge, the tape reinforcing fibers and the boron fibers having about the same failure strain.
Claim 2
Dependent Claim
90 words
A composite structure comprising a resin tape reinforced with fibers other than boron fibers having a tungsten boride core, the reinforcing fibers being parallel to edges of the tape, and segments of the tape being stacked one upon another so as to form a plurality of plies; and a boron fiber having a tungsten boride core positioned along an edge of each tape segment and having a length about equal to the length of the edge, the tape reinforcing fibers and the boron fibers having about the same failure strain.
Claim 3
Dependent Claim
27 words
The composite structure according to claim 1 in which a single boron fiber having a tungsten boride core in positioned along an edge of each tape segment.
Claim 4
Dependent Claim
29 words
The composite structure according to claim 1 in which the fiber-reinforced resin tape is formed with a thermosetting resin as the matrix and graphite fibers as the reinforcing material.
Claim 5
Dependent Claim
16 words
The composite structure according to claim 3, in which the thermosetting resin is an epoxy resin.
Claim 6
Dependent Claim
28 words
The composite structure according to claim 4 in which the tape segments are stacked so that their edges and the boron fibers positioned there along are vertically non-aligned.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-03-09 | 1984-09-08 | 1985-03-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-03-09 | 1988-09-08 | 1989-03-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-03-09 | 1992-09-08 | 1993-03-10 | $7700.00 | Window Closed / Lapsed |