US4635882A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for reducing low to mid frequency interior noise
Assignee: Boeing Co
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Filing: 1985-04-18
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Granted: 1987-01-13
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Expires: 2005-04-18
Abstract
Abstract A method and apparatus for reducing the low to mid frequency interior noise of a reinforced skin structure, such as the cabin of a jet aircraft, by reducing the vibration response of the structure to low to mid frequency disturbances is disclosed. Interior noise is reduced by forming the structure such that the skin panels bounded by reinforcing components have a higher fundamental frequency than the combined bending and tuning fork frequency of reinforcing components with spaced apart legs that support the skin; and, damping the bending, tuning fork and torsional vibration of the reinforcing components. Damping is accomplished by bridging the spaced apart legs of the reinforcing components with rigid elements, viscoelastically attached at either end to the legs. Preferably, the viscoelastic attachment is via flanges that extend outwardly from the legs. The entire length of the reinforcing components may be spanned by a single rigid element; or, a series of spaced apart rigid elements may span the reinforcing components. When spaced apart rigid elements are used, preferably, they are centered at the antinodal points of the reinforcing components, as determined by the frequency of the noise produced in the interior of the body by the vibration of an undamped reinforcing component. If the interior noise covers a spectrum, the antinodal points are determined by the frequency of the major contributor(s) to the interior noise.
Inventors
- 👤 Gautam SenGupta
- 👤 Byron R. Spain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 21:26
CPC Classifications
B; B64; B64C; B64C1/00; B64C1/06; B64C1/40; B64C2001/0054; B64C2001/0081; Y; Y02; Y02T; Y02T50/00; Y02T50/40
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
122 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure formed of a skin supported by a plurality of elongate reinforcing components having spaced apart legs oriented such that said spaced apart legs project away from said skin and are free to vibrate, said method comprising the steps of: forming said reinforced skin structure such that areas of the skin bounded by said reinforcing components having a higher fundamental frequency than the bending and tuning fork frequency of said elongate reinforcing components with spaced apart legs; and damping the bending, tuning fork and torsional vibration of said elongate reinforcing components by spanning said spaced apart legs with rigid elements viscoelastically attached to said spaced apart legs.
Claim 2
Independent Claim
122 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure formed of a skin supported by a plurality of elongate reinforcing components having spaced apart legs oriented such that said spaced apart legs project away from said skin and are free to vibrate, said method comprising the steps of: forming said reinforced skin structure such that areas of the skin bounded by said reinforcing components having a higher fundamental frequency than the bending and tuning fork frequency of said elongate reinforcing components with spaced apart legs; and damping the bending, tuning fork and torsional vibration of said elongate reinforcing components by spanning said spaced apart legs with rigid elements viscoelastically attached to said spaced apart legs.
Claim 3
Dependent Claim
35 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 1 wherein said damping extends along substantially the entire length of said elongate reinforcing components.
Claim 4
Dependent Claim
38 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 1 wherein said damping occurs at spaced apart regions located along the length of said elongate reinforcing components.
Claim 5
Dependent Claim
71 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 3, said noise including a spectral component constituting a major contributor of said noise, wherein said spaced apart regions are located at the antinodal points of said elongate reinforcing components based on the frequency of said major contributor to the low to mid frequency interior noise of said reinforced skin structure.
Claim 6
Independent Claim
145 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure formed of a skin supported by a plurality of elongate reinforcing components having spaced apart legs and flanges extending outwardly from said spaced apart legs, said elongate reinforcing components being oriented such that said spaced apart legs project away from said skin and are free to vibrate, said method comprising the steps of: forming said reinforced skin structure such that areas of the skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said elongate reinforcing components with spaced apart legs having outwardly extending flanges; and damping the bending, tuning fork and torsional vibration of said elongate reinforcing components by spanning said spaced apart legs with rigid elements viscoelastically attached to said outwardly extending flanges of said spaced apart legs.
Claim 7
Independent Claim
145 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure formed of a skin supported by a plurality of elongate reinforcing components having spaced apart legs and flanges extending outwardly from said spaced apart legs, said elongate reinforcing components being oriented such that said spaced apart legs project away from said skin and are free to vibrate, said method comprising the steps of: forming said reinforced skin structure such that areas of the skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said elongate reinforcing components with spaced apart legs having outwardly extending flanges; and damping the bending, tuning fork and torsional vibration of said elongate reinforcing components by spanning said spaced apart legs with rigid elements viscoelastically attached to said outwardly extending flanges of said spaced apart legs.
Claim 8
Dependent Claim
35 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 5 wherein said damping extends along substantially the entire length of said elongate reinforcing components.
Claim 9
Dependent Claim
38 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 5 wherein said damping occurs at spaced apart regions located along the length of said elongate reinforcing components.
Claim 10
Dependent Claim
71 words
A method of reducing the low to mid frequency interior noise of a reinforced skin structure as claimed in claim 7, said noise including a spectral component constituting a major contributor of said noise, wherein said spaced apart regions are located at the antinodal points of said elongate reinforcing components based on the frequency of said major contributor to the low to mid frequency interior noise of said reinforced skin structure.
Claim 11
Dependent Claim
117 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner, said reinforcing components and said skin being formed such that the areas of said skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said reinforcing components; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components; and viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs.
Claim 12
Dependent Claim
117 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner, said reinforcing components and said skin being formed such that the areas of said skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said reinforcing components; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components; and viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs.
Claim 13
Dependent Claim
22 words
A reinforced skin structure as claimed in claim 9 wherein said rigid elements span substantially the entire length of said reinforcing components.
Claim 14
Dependent Claim
18 words
A reinforced skin structure as claimed in claim 10 wherein said rigid elements include a plurality of apertures.
Claim 15
Dependent Claim
25 words
A reinforced skin structure as claimed in claim 9 wherein said rigid elements are positioned at predetermined regions along the length of said reinforcing components.
Claim 16
Dependent Claim
23 words
A reinforced skin structure as claimed in claim 12 wherein predetermined edges of said rigid elements curve outwardly to stiffen said rigid elements.
Claim 17
Dependent Claim
50 words
A reinforced skin structure as claimed in claim 9 including a rigid base element viscoelastically attached to each of said spaced apart legs of said reinforcing components, along the length thereof, and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said rigid base elements.
Claim 18
Dependent Claim
43 words
A reinforced skin structure as claimed in claim 9 wherein said spaced apart legs of said plurality of reinforcing components have outwardly extending flanges and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said outwardly extending flanges.
Claim 19
Dependent Claim
22 words
A reinforced skin structure as claimed in claim 15 wherein said rigid elements span substantially the entire length of said reinforcing components.
Claim 20
Dependent Claim
18 words
A reinforced skin structure as claimed in claim 16 wherein said rigid elements include a plurality of apertures.
Claim 21
Dependent Claim
25 words
A reinforced skin structure as claimed in claim 15 wherein said rigid elements are positioned at predetermined regions along the length of said reinforcing components.
Claim 22
Dependent Claim
23 words
A reinforced skin structure as claimed in claim 18 wherein predetermined edges of said rigid elements curve outwardly to stiffen said rigid elements.
Claim 23
Dependent Claim
116 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components having spaced apart legs support a skin, said spaced apart legs projecting away from said skin and being free to vibrate in a tuning fork manner, said reinforcing components and said skin being formed such that the areas of said skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said reinforcing components, the improvement comprising: a plurality of rigid damping elements positioned so as to span the spaced apart legs of said reinforcing components; and viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs of said reinforcing components.
Claim 24
Dependent Claim
116 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components having spaced apart legs support a skin, said spaced apart legs projecting away from said skin and being free to vibrate in a tuning fork manner, said reinforcing components and said skin being formed such that the areas of said skin bounded by said reinforcing components have a higher fundamental frequency than the bending and tuning fork frequency of said reinforcing components, the improvement comprising: a plurality of rigid damping elements positioned so as to span the spaced apart legs of said reinforcing components; and viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs of said reinforcing components.
Claim 25
Dependent Claim
19 words
The improvement claimed in claim 20 wherein said rigid elements span substantially the entire length of said reinforcing components.
Claim 26
Dependent Claim
15 words
The improvement claimed in claim 21 wherein said rigid elements include a plurality of apertures.
Claim 27
Dependent Claim
22 words
The improvement claimed in claim 20 wherein said rigid elements are positioned at predetermined regions along the length of said reinforcing components.
Claim 28
Dependent Claim
20 words
The improvement claimed in claim 23 wherein predetermined edges of said rigid elements curve outwardly to stiffen said rigid elements.
Claim 29
Dependent Claim
48 words
The improvement claimed in claim 20 including a rigid base element viscoelastically attached to each of said spaced apart legs of said reinforcing components, along the length thereof, and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said elongate rigid base elements.
Claim 30
Dependent Claim
40 words
The improvement claimed in claim 20 wherein said spaced apart legs of said plurality of reinforcing components have outwardly extending flanges and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said outwardly extending flanges.
Claim 31
Dependent Claim
19 words
The improvement claimed in claim 26 wherein said rigid elements span substantially the entire length of said reinforcing components.
Claim 32
Dependent Claim
15 words
The improvement claimed in claim 27 wherein said rigid elements include a plurality of apertures.
Claim 33
Dependent Claim
22 words
The improvement claimed in claim 26 wherein said rigid elements are positioned at predetermined regions along the length of said reinforcing components.
Claim 34
Dependent Claim
19 words
The improvement claimed in claim 29 wherein predetermined edges of said rigid elements outwardly to stiffen said rigid elements.
Claim 35
Dependent Claim
90 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components along substantially the entire length of said reinforcing components; and, viscoelastic means for attaching the ends of said rigid elements of said spaced apart legs.
Claim 36
Dependent Claim
90 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components along substantially the entire length of said reinforcing components; and, viscoelastic means for attaching the ends of said rigid elements of said spaced apart legs.
Claim 37
Dependent Claim
18 words
A reinforced skin structure as claimed in claim 31 wherein said rigid elements include a plurality of apertures.
Claim 38
Dependent Claim
43 words
A reinforced skin structure as claimed in claim 31 wherein said spaced apart legs of said plurality of reinforcing components have outwardly extending flanges and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said outwardly extending flanges.
Claim 39
Dependent Claim
18 words
A reinforced skin structure as claimed in claim 33 wherein said rigid elements include a plurality of apertures.
Claim 40
Dependent Claim
104 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner; a rigid base element viscoelastically attached to each of said spaced apart legs of said reinforcing components, along the length thereof; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components; and, viscoelastic means for attaching the ends of said plurality of rigid elements to said rigid base elements.
Claim 41
Dependent Claim
104 words
A reinforced skin structure comprising: a plurality of elongate reinforcing components having spaced apart legs; a skin mounted on said reinforcing components such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner; a rigid base element viscoelastically attached to each of said spaced apart legs of said reinforcing components, along the length thereof; a plurality of rigid elements positioned so as to span the spaced apart legs of said reinforcing components; and, viscoelastic means for attaching the ends of said plurality of rigid elements to said rigid base elements.
Claim 42
Dependent Claim
89 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components having spaced apart legs support a skin, said spaced apart legs projecting away from said skin and being free to vibrate in a tuning fork manner, the improvement comprising: a plurality of rigid damping elements positioned so as to span the spaced apart legs of said reinforcing components along substantially the entire length of said reinforcing components; and, viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs of said reinforcing components.
Claim 43
Dependent Claim
89 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components having spaced apart legs support a skin, said spaced apart legs projecting away from said skin and being free to vibrate in a tuning fork manner, the improvement comprising: a plurality of rigid damping elements positioned so as to span the spaced apart legs of said reinforcing components along substantially the entire length of said reinforcing components; and, viscoelastic means for attaching the ends of said rigid elements to said spaced apart legs of said reinforcing components.
Claim 44
Dependent Claim
15 words
The improvement claimed in claim 36 wherein said rigid elements include a plurality of apertures.
Claim 45
Dependent Claim
40 words
The improvement claimed in claim 36 wherein said spaced apart legs of said plurality of reinforcing components have outwardly extending flanges and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said outwardly extending flanges.
Claim 46
Dependent Claim
15 words
The improvement claimed in claim 38 wherein said rigid elements include a plurality of apertures.
Claim 47
Dependent Claim
172 words
A reinforced skin structure comprising: frame means for supporting a plurality of elongate reinforcing components; a plurality of U-shaped elongate reinforcing components each having a pair of spaced apart legs, said plurality of reinforcing components being mounted on said frame means such that said plurality of elongate reinforcing components are spaced from one another; a skin mounted on said plurality of reinforcing components, said plurality of reinforcing components being oriented such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner in regions where said reinforcing components are not mounted on said frame means; a plurality of rigid, generally flat elements positioned to span the spaced apart legs of said reinforcing components in said regions where said reinforcing components are not mounted on said frame means and are free to vibrate in a tuning fork manner; and, viscoelastic means for attaching the ends of said rigid, generally flat elements to said spaced apart legs of said reinforcing components.
Claim 48
Dependent Claim
172 words
A reinforced skin structure comprising: frame means for supporting a plurality of elongate reinforcing components; a plurality of U-shaped elongate reinforcing components each having a pair of spaced apart legs, said plurality of reinforcing components being mounted on said frame means such that said plurality of elongate reinforcing components are spaced from one another; a skin mounted on said plurality of reinforcing components, said plurality of reinforcing components being oriented such that said spaced apart legs of said reinforcing components project away from said skin and are free to vibrate in a tuning fork manner in regions where said reinforcing components are not mounted on said frame means; a plurality of rigid, generally flat elements positioned to span the spaced apart legs of said reinforcing components in said regions where said reinforcing components are not mounted on said frame means and are free to vibrate in a tuning fork manner; and, viscoelastic means for attaching the ends of said rigid, generally flat elements to said spaced apart legs of said reinforcing components.
Claim 49
Dependent Claim
23 words
A reinforced skin structure as claimed in claim 40 wherein predetermined edges of said rigid elements curve outwardly to stiffen said rigid elements.
Claim 50
Dependent Claim
43 words
A reinforced skin structure as claimed in claim 40, wherein said spaced apart legs of said plurality of reinforcing components having outwardly extending flanges and wherein said plurality of rigid elements are viscoelastically attached by said viscoelastic means to said outwardly extending flanges.
Claim 51
Dependent Claim
22 words
A reinforced skin structure as claimed in claim 40 wherein said rigid elements span substantilly the entire length of said reinforcing components.
Claim 52
Dependent Claim
18 words
A reinforced skin structure as claimed in claim 43, wherein said rigid elements include a plurality of apertures.
Claim 53
Dependent Claim
150 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components each having a pair of spaced apart legs are supported in a spaced apart manner by frame means, said plurality of reinforcing components supporting a skin in a manner such that said spaced apart legs of said plurality of reinforcing components project away from said skin and are free to vibrate in a tuning fork manner in regions where said reinforcing components are not supported by said frame means, the improvement comprising: a plurality of rigid, generally flat damping elements positioned to span the spaced apart legs of said reinforcing components in said regions where said reinforcing components are not supported by said frame means and are free to vibrate in a tuning fork manner; and, viscoelastic means for attaching the ends of said rigid, generally flat damping elements to said spaced apart legs of said reinforcing components.
Claim 54
Dependent Claim
150 words
In a reinforced skin structure wherein a plurality of elongate reinforcing components each having a pair of spaced apart legs are supported in a spaced apart manner by frame means, said plurality of reinforcing components supporting a skin in a manner such that said spaced apart legs of said plurality of reinforcing components project away from said skin and are free to vibrate in a tuning fork manner in regions where said reinforcing components are not supported by said frame means, the improvement comprising: a plurality of rigid, generally flat damping elements positioned to span the spaced apart legs of said reinforcing components in said regions where said reinforcing components are not supported by said frame means and are free to vibrate in a tuning fork manner; and, viscoelastic means for attaching the ends of said rigid, generally flat damping elements to said spaced apart legs of said reinforcing components.
Claim 55
Dependent Claim
20 words
The improvement claimed in clam 45 wherein predetermined edges of said rigid elements curve outwardly to stiffen said rigid elements.
Claim 56
Dependent Claim
40 words
The improvement claimed in clam 45 wherein said spaced apart legs of said plurality of reinforcing components have outwardly extending flanges and wherein said plurality of rigid elements are viscoelasticaly attached by said viscoelastic means to said outwardly extending flanges.
Claim 57
Dependent Claim
19 words
The improvement claimed in claim 47 wherein said rigid elements span substantially the entire length of said reinforcing components.
Claim 58
Dependent Claim
15 words
The improvement claimed in claim 48 wherein said rigid elements include a plurality of apertures.
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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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |