US5250132A
Expired / Lapsed
US
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Method of making a composite laminate having an internally damped constraining layer
Assignee: Northrop Grumman Systems Corp
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Filing: 1991-12-02
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Granted: 1993-10-05
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Expires: 2011-12-02
Abstract
Abstract A method of making a composite laminate having an internally damped constraining layer sandwiched between first and second load-bearing members. The constraining layer and load-bearing members are of a filament reinforced resin matrix, with the gelation temperature of the resin matrices of the constraining layer and load-bearing members being different. During a single cure cycle, the temperature of the assembled unit is increased such that one of the resin matrices hardens first while the other hardens at a later point in time and at a higher temperature, with the process ensuring for an adequate bond between the resin matrices and viscoelastic damping layers positioned on either side of the constraining layer members. The constraining layer members are affixed with gaps between them and a compliant tubing is placed within the gaps.
Inventors
- 👤 Christy K. Lapp
- 👤 Paul D. Grund
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:14
CPC Classifications
B; B29; B29C; B29C70/00; B29C70/04; B29C70/28; B29C70/30; B29C70/32; B29C70/323; B29C70/326; B29C53/00; B29C53/56; B29C53/58; B29C53/583; B29C53/80; B29C53/84; B29C53/845; B29C35/00; B29C35/02; B29L; B29L2023/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
258 words
A method of forming a composite laminate having an internally damped constraining layer, comprising the steps of: a. forming a plurality of uncured composite constraining layer members each of a filament reinforced resin matrix having a certain gelation temperature; b. forming a first composite load-bearing member of a filament reinforced resin matrix having a certain gelation temperature different than the gelation temperature of said resin matrix of said constraining layer members; c. applying a first viscoelastic damping layer to said first composite load-bearing member prior to curing; d. applying said constraining layer members over said first viscoelastic layer in a predetermined pattern which leaves gaps between said applied layers, and prior to curing, while said resin matrix of said constraining layer members is still tacky; e. applying a second viscoelastic damping layer over said constraining layer members; f. forming a second composite load-bearing member over said second viscoelastic damping layer and being of a filament reinforced resin matrix having a gelation temperature the same as the gelation temperature of said resin matrix of said first composite load-bearing member; g. curing the thus fabricated structure by placing it in an oven and increasing the temperature thereof sequentially through the gelation temperatures of said resin matrices until said composite laminate is cured; h. the gelatin temperature of said resin matrix of said constraining layer members being higher than that of said resin matrices of said load-bearing members so that the resin matrices of said load-bearing members are completely gelled before the resin matrix of said constraining layer members begin gelation.
Claim 2
Independent Claim
258 words
A method of forming a composite laminate having an internally damped constraining layer, comprising the steps of: a. forming a plurality of uncured composite constraining layer members each of a filament reinforced resin matrix having a certain gelation temperature; b. forming a first composite load-bearing member of a filament reinforced resin matrix having a certain gelation temperature different than the gelation temperature of said resin matrix of said constraining layer members; c. applying a first viscoelastic damping layer to said first composite load-bearing member prior to curing; d. applying said constraining layer members over said first viscoelastic layer in a predetermined pattern which leaves gaps between said applied layers, and prior to curing, while said resin matrix of said constraining layer members is still tacky; e. applying a second viscoelastic damping layer over said constraining layer members; f. forming a second composite load-bearing member over said second viscoelastic damping layer and being of a filament reinforced resin matrix having a gelation temperature the same as the gelation temperature of said resin matrix of said first composite load-bearing member; g. curing the thus fabricated structure by placing it in an oven and increasing the temperature thereof sequentially through the gelation temperatures of said resin matrices until said composite laminate is cured; h. the gelatin temperature of said resin matrix of said constraining layer members being higher than that of said resin matrices of said load-bearing members so that the resin matrices of said load-bearing members are completely gelled before the resin matrix of said constraining layer members begin gelation.
Claim 3
Independent Claim
232 words
A method of forming a composite laminate having an internally damped constraining layer, comprising the steps of: a. forming a plurality of uncured composite constraining layer members each of a filament reinforced resin matrix having a certain gelation temperature; b. forming a first composite load-bearing member of a filament reinforced resin matrix having a certain gelation temperature different than the gelation temperature of said resin matrix of said constraining layer members; c. applying a first viscoelastic damping layer to said first composite load-bearing member prior to curing; d. applying said constraining layer members over said first viscoelastic layer in a predetermined pattern which leaves gaps between said applied layers, and prior to curing, while said resin matrix of said constraining layer members is still tacky; e. applying a second viscoelastic damping layer over said constraining layer members; f. forming a second composite load-bearing member over said second viscoelastic damping layer and being of a filament reinforced resin matrix having a gelation temperature the same as the gelation temperature of said resin matrix of said first composite load-bearing member; g. curing the thus fabricated structure by placing it in an oven and increasing the temperature thereof to the lower of the gelation temperatures of the resin matrices; h. maintaining said lower temperature for a predetermined period of time to complete the gelation; and i. thereafter increasing the temperature to the higher gelation temperature.
Claim 4
Independent Claim
232 words
A method of forming a composite laminate having an internally damped constraining layer, comprising the steps of: a. forming a plurality of uncured composite constraining layer members each of a filament reinforced resin matrix having a certain gelation temperature; b. forming a first composite load-bearing member of a filament reinforced resin matrix having a certain gelation temperature different than the gelation temperature of said resin matrix of said constraining layer members; c. applying a first viscoelastic damping layer to said first composite load-bearing member prior to curing; d. applying said constraining layer members over said first viscoelastic layer in a predetermined pattern which leaves gaps between said applied layers, and prior to curing, while said resin matrix of said constraining layer members is still tacky; e. applying a second viscoelastic damping layer over said constraining layer members; f. forming a second composite load-bearing member over said second viscoelastic damping layer and being of a filament reinforced resin matrix having a gelation temperature the same as the gelation temperature of said resin matrix of said first composite load-bearing member; g. curing the thus fabricated structure by placing it in an oven and increasing the temperature thereof to the lower of the gelation temperatures of the resin matrices; h. maintaining said lower temperature for a predetermined period of time to complete the gelation; and i. thereafter increasing the temperature to the higher gelation temperature.
Claim 5
Dependent Claim
22 words
A method according to claim 2, which includes the step of: a. maintaining said first named temperature for a period of hours.
Claim 6
Dependent Claim
30 words
A method according to claim 2, which includes the step of: a. increasing the temperature to a value above the higher of said gelation temperatures to cure the composite laminate.
Claim 7
Dependent Claim
34 words
A method according to claim 2, which includes the step of: a. raising said temperature from said lower to said higher temperature at a rate of approximately 1 to 5 degrees F per minute.
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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) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |