US4350728A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cross reinforcement in a graphite-epoxy laminate
Assignee: United States Department of the Navy
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Filing: 1980-10-02
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Granted: 1982-09-21
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Expires: 2000-10-02
Abstract
Abstract Interlaminar shear strength of an aircraft wing made of graphite-epoxy laate is significantly increased by embedding thin steel wires in preselected locations of high stress in alternating rows ±45° to the plane of the laminate before it is cured. This cross wire reinforcement prevents brittle delamination, arrests propagation of delamination and reduces scatter of interlaminar strength.
Inventors
- 👤 Shih L. Huang
- 👤 Edward J. McQuillen
- 👤 Robert J. Richey, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 21:39
CPC Classifications
B; B29; B29D; B29D99/00; B29D99/0003; B29C; B29C65/00; B29C65/56; B29C65/562; B29C65/564; B29C66/00; B29C66/01; B29C66/05; B29C66/10; B29C66/11; B29C66/112; B29C66/1122; B29C66/13; B29C66/131; B29C66/40; B29C66/41; B29C66/45; B29C66/47; B29C66/474; B29C66/50; B29C66/51; B29C66/52; B29C66/524; B29C66/70; B29C66/71; B29C66/72; B29C66/721; B29C70/00; B29C70/04; B29C70/06; B29C70/10; B29C70/16; B29C70/24; B32; B32B; B32B27/00; B32B27/12; B32B7/00; B32B7/04; B32B7/12; B64; B64C; B64C3/00; B64C3/20; B29C66/7212; B29C66/7214; B29C66/72141; B29K; B29K2063/00; B29K2307/00; B29L; B29L2031/00; B29L2031/30; B29L2031/3076; B29L2031/3082; B29L2031/3085; B32B2605/00; B32B2605/18; Y; Y02; Y02T; Y02T50/00; Y02T50/40; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24058; Y10T428/24132; Y10T428/29; Y10T428/2913; Y10T428/2915; Y10T428/298; Y10T428/30; Y10T428/31504; Y10T428/31511; Y10T428/31515; Y10T428/31522
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
89 words
A lightweight reinforced composite material for use in structures having high stress applications, comprising: a plurality of plies of a fibrous resin adhesively bonded together to form a laminate; and a plurality of reinforcing rods embedded in said laminate to span the distance between the outer surfaces thereof, said rods being positioned in adjacent pairs along measured critically highest stress planes in said laminate, said pairs being parallel to said stress planes on opposite sides thereof and angularly displaced in opposite directions to planes normal to said stress planes.
Claim 2
Dependent Claim
89 words
A lightweight reinforced composite material for use in structures having high stress applications, comprising: a plurality of plies of a fibrous resin adhesively bonded together to form a laminate; and a plurality of reinforcing rods embedded in said laminate to span the distance between the outer surfaces thereof, said rods being positioned in adjacent pairs along measured critically highest stress planes in said laminate, said pairs being parallel to said stress planes on opposite sides thereof and angularly displaced in opposite directions to planes normal to said stress planes.
Claim 3
Dependent Claim
19 words
A composite material according to claim 1 further comprising: a substructure bonded to said laminate for reinforcing said structures.
Claim 4
Dependent Claim
24 words
A composite material according to claim 2, further comprising: said stress planes being located along the bonded interface of said substructure and said laminate.
Claim 5
Dependent Claim
21 words
A composite material according to claim 1, further comprising: said stress planes being located along the areas of hgh interlaminar stress.
Claim 6
Dependent Claim
29 words
The composite material according to claim 1 further comprising: said rods being angularly displaced alternately plus forty-five and minus forty-five degrees to a plane normal to the stress planes.
Claim 7
Dependent Claim
13 words
The composite material according to claim 5 further comprising: said rods being metallic.
Claim 8
Dependent Claim
24 words
The composite material according to claim 6 further comprising: said rods being of steel wire and having a diameter in the range of 0.008-0.020.
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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) | 1985-09-20 | 1986-03-22 | 1986-09-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-09-20 | 1990-03-22 | 1990-09-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-09-20 | 1994-03-22 | 1994-09-21 | $7700.00 | Window Closed / Lapsed |