Patent US4274901A successfully refreshed from Google Patents.
US4274901A
Expired / Lapsed
US
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Method of making a partial interlaminar separation composite system
Assignee: National Aeronautics and Space Administration
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Filing: 1980-02-07
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Granted: 1981-06-23
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Expires: 2000-02-07
Abstract
Abstract This invention relates to an interlaminar separation system for composites wherein a thin layer of a perforated foil film is interposed between adjacent laminae of a composite formed from prepreg tapes to thereby permit laminae adherence through the perforations and produce a composite structure having improved physical property characteristics.
Inventors
- 👤 Wolf Elber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:46
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/12; B29; B29C; B29C70/00; B29C70/04; B29C70/06; B29C70/08; B29C70/086; B29C70/28; B29C70/30; B29C70/34; B32B27/36; B32B3/00; B32B3/26; B32B3/266; B32B7/00; B32B7/04; B29K; B29K2063/00; B29K2067/00; B29K2067/06; B29K2101/00; B29K2101/12; B29K2105/00; B29K2105/06; B29K2105/08; B29K2105/10; B29K2105/101; B29K2105/108; B29K2307/00; B32B2250/00; B32B2250/42; B32B2260/00; B32B2260/04; B32B2260/046; B32B2307/00; B32B2307/50; B32B2307/542; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1052; Y10T156/1056; Y10T156/1062; Y10T156/1075
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
172 words
A method for enhancing interlaminar shear strength for composite laminates comprising: providing prepreg resin impregnated fiber tape material having the fibers therein running the length of the tape; cutting the prepreg tape into a plurality of desired lengths; laying up and stacking the plurality of lengths of tape in layers of the desired dimensions and to a predetermined thickness; providing a layer formed by a plurality of thin perforated polyester film strips of essentially the same length and width dimensions as the prepreg tape layers; positioning one layer of the perforated film strips between each layer of prepreg tape and curing the stacked tape and film strip assembly into a unitary mass under vacuum, pressure and an elevated temperature of at least 465° K. for at least 60 minutes; cooling the cured assembly to a minimum of 400° K. while maintaining the vacuum and pressure and, after releasing the vacuum and pressure, permitting the assembly to cool to room temperature to thereby yield a composite laminate structure having improved physical property characteristics.
Claim 2
Independent Claim
172 words
A method for enhancing interlaminar shear strength for composite laminates comprising: providing prepreg resin impregnated fiber tape material having the fibers therein running the length of the tape; cutting the prepreg tape into a plurality of desired lengths; laying up and stacking the plurality of lengths of tape in layers of the desired dimensions and to a predetermined thickness; providing a layer formed by a plurality of thin perforated polyester film strips of essentially the same length and width dimensions as the prepreg tape layers; positioning one layer of the perforated film strips between each layer of prepreg tape and curing the stacked tape and film strip assembly into a unitary mass under vacuum, pressure and an elevated temperature of at least 465° K. for at least 60 minutes; cooling the cured assembly to a minimum of 400° K. while maintaining the vacuum and pressure and, after releasing the vacuum and pressure, permitting the assembly to cool to room temperature to thereby yield a composite laminate structure having improved physical property characteristics.
Claim 3
Dependent Claim
20 words
The process of claim 1 wherein the same fiber orientation is maintained for each prepreg tape layer during layup assembly.
Claim 4
Dependent Claim
26 words
The process of claim 1 wherein the fiber orientation of each prepreg tape layer is angularly disposed relative to the fiber orientation of each adjacent layer.
References Cited (Backward Citations)
GB305694A
Cited
US1943757A
Cited
US2054210A
Cited
FR1167342A
Cited
US3442741A
Cited
US4063981A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-22 | 1984-12-22 | 1985-06-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-22 | 1988-12-22 | 1989-06-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-22 | 1992-12-22 | 1993-06-23 | $7700.00 | Window Closed / Lapsed |