|Publication number||US20060059828 A1|
|Application number||US 10/903,419|
|Publication date||Mar 23, 2006|
|Filing date||Jul 29, 2004|
|Priority date||Jul 29, 2004|
|Also published as||WO2007013873A2, WO2007013873A3|
|Publication number||10903419, 903419, US 2006/0059828 A1, US 2006/059828 A1, US 20060059828 A1, US 20060059828A1, US 2006059828 A1, US 2006059828A1, US-A1-20060059828, US-A1-2006059828, US2006/0059828A1, US2006/059828A1, US20060059828 A1, US20060059828A1, US2006059828 A1, US2006059828A1|
|Inventors||James Stevenson, Roger Williamson, Ion Vintilescu, Vincent Chung|
|Original Assignee||Stevenson James F, Williamson Roger B, Vintilescu Ion V, Vincent Chung|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (13), Classifications (14), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present invention relates to noise suppression structures and, more particularly, to noise suppression structures for aircraft ducts and plenums, and methods of repairing the structures.
Many aircraft are powered by jet engines. In most instances, jet engines include one or more gas-powered turbine engines, auxiliary power units (APUs), and/or environmental control systems (ECSs), which can generate both thrust to propel the aircraft and electrical energy to power systems installed in the aircraft. Although most aircraft engines are generally safe, reliable, and efficient, the engines do exhibit certain drawbacks. For example, the turbine engines, as well as other components that make up the engine, can be sources of unwanted noise, especially during aircraft take-off and landing operations. Moreover, APUs and ECSs can be sources of unwanted ramp noise. Thus, various governmental rules and regulations aimed at mitigating such noise sources have been enacted.
To address, and at least somewhat alleviate, the unwanted noise emanating from aircraft noise sources, and to thereby comply with the above-noted rules and regulations, various types of noise reduction treatments have been developed. For example, one type of noise reduction treatment that has been developed for use in aircraft ducts is a noise suppression panel. In many instances, noise suppression panels are flat or contoured, and include a honeycomb structure disposed between a backing plate and a face plate. Other noise suppression materials and structure may also be disposed between the backing plate and face plate. The noise suppression panels are typically placed on the interior surface of engine or APU inlet and/or outlet plenums, as necessary, to reduce noise emanations.
Periodically, these noise suppression panels may become damaged from normal wear. Voids may form in the panel, or alternatively, air gaps between the face plate and honeycomb structure may appear. Conventionally, the repair of these damaged sections include, for example, applying liquid resin to the voids or air gaps and subsequent curing of the panel. Other repair methods have included filling the voids or damaged sections with a clay-like substance. However, neither cured resins nor clay have acoustic damping properties, and thus, can reduce, rather than maintain or enhance, the noise suppression capabilities of the panel.
The foam core material in the noise suppression panels may contain manufacturing defects, such as voids or uneven surfaces. In these cases, the defective panels may not operate as intended and have historically been entirely discarded. As a result, the costs of aircraft manufacture and/or maintenance may increase.
Hence, there is a need for a method of repairing a noise suppression panel that restores the noise suppression capabilities of the panel to its original specifications, and/or is less costly compared to known methods, and/or maintains noise suppression capabilities over a relatively wide frequency range. The present invention addresses one or more of these needs.
A method is provided for repairing a defect in a noise suppression panel.
In one embodiment, and by way of example only, first, a section of the noise suppression panel that includes the defect is removed to thereby create a cavity in the panel. Next, an insert configured to mate with the cavity is formed from a material having acoustic damping properties. Then, the insert is placed at least partially within the cavity.
In another exemplary embodiment, a method is provided for repairing a defect in a noise suppression panel having a back plate, a face plate and a bulk absorber disposed therebetween. The method includes removing at least a portion of the face plate, removing a section of the noise suppression panel that includes the defect to thereby create a cavity in the panel, forming an insert configured to mate with the cavity from a material having acoustic damping properties, placing the insert into the cavity, and bonding the insert to the back plate.
Other independent features and advantages of the preferred method will become apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Before proceeding with the detailed description, it is to be appreciated that the described embodiment is not limited to use in conjunction with a particular type of engine, or in a particular type of vehicle. Thus, although the present embodiment is, for convenience of explanation, described as being implemented in an aircraft environment, it will be appreciated that it can be implemented in various other types of vehicles, and in various other systems and environments.
Turning now to the description, and with reference first to
The face plate 104 is constructed of any one of numerous types of materials such as, for example, aluminum, and carbon composites. In one exemplary embodiment, the face plate 104 is constructed of BMI, and is perforated to a desired percent open area (POA) value. As is generally known, relatively low POA values (e.g., ˜5%) provide acoustic resistance, whereas relatively high POA values (e.g., ˜30%) provide acoustic transparency. In a particular preferred embodiment, the face plate 104 is perforated to a POA value greater than 30% to ensure the face plate 104 is acoustically transparent to any incident sound. In another exemplary embodiment, the face plate 104 is a screen. Similar to the back plate 102, and as will be described further below, the face plate 104 is also preferably bonded to the bulk absorber 106 during manufacture of the panel 100.
The bulk absorber 106 is disposed between the back plate 102 and face plate 104 and, as was mentioned above, is preferably directly bonded to each plate 102, 104 during manufacture of the panel 100. The bulk absorber 106 may be constructed of any one of numerous materials, such as, for example, foamable material, material having honeycomb cavities therein, honeycomb material filled at least partially with epoxy for structural enhancement, or any one of numerous other type of acoustic damping material. In one exemplary embodiment, the bulk absorber 106 is an open cell foam bulk absorber, such as the type disclosed in U.S. patent application Ser. No. ______ entitled “Noise Suppression Structure Manufacturing Method” filed on May 20, 2004 and U.S. patent application Ser. No. ______ entitled “Noise Suppression Structure and Method of Making Same” filed on Feb. 20, 2004.
Occasionally, during manufacture or as a result of normal wear, the noise suppression panel 100 may become damaged or defective. The damage may take any one of numerous forms. For example, and as shown more clearly in
Regardless of the particular type of defect, the bulk absorber 106 is preferably repaired and the repair method of the present invention is preferably employed. The overall process 500 is illustrated in
As briefly mentioned previously and as shown in
In some instances, the shape of the cavity walls 410 may provide an improved surface to which a repair may be made. For example, the cavity walls 410 may have a beveled (as illustrated in
With reference to
The insert 408 can be formed by any one of numerous methods. Some examples include, but are not limited to machining, cutting, or chiseling the insert 408 out of the material 406. Any one of numerous tools, such as a straight circular saw or a hole cutter with beveled walls may be used to form the insert 408 from the material 406. As those with skill in the art may appreciate, tools used for forming the insert 408 and tools for creating the cavity 404 may be matched sets having a variety of graded cutter sizes that may be useful to cover the expected range of defect sizes.
It will additionally be appreciated that the acoustic damping material 406 may be any one of a number of materials that suitably suppress noise to a predetermined noise level. Preferably, the acoustic damping material 406 damps aircraft noise by between about 5 and 10 dB, however, as appreciated by those skilled in avionics, the acoustic damping material 406 most preferably meets federal noise level standards mandated by the Federal Aviation Administration. Examples of suitable materials include but are not limited to, the bulk absorber 106 materials mentioned above, conventional honeycomb treatments, and those materials disclosed in U.S. patent application Ser. No. ______ entitled “Noise Suppression Structure Manufacturing Method” filed on May 20, 2004, and U.S. patent application Ser. No. ______ entitled “Noise Suppression Structure and Method of Making Same” filed on Feb. 20, 2004.
The acoustic damping material 406 can be the same material from which the bulk absorber 106 is manufactured. However, this is not a requirement; accordingly, the acoustic damping material 406 and bulk absorber 106 material may be different materials. In one exemplary embodiment, the acoustic damping material 406 has mechanical properties that are at least comparable to those of the bulk absorber 106 material to maintain the mechanical integrity of the bulk absorber 106.
Turning now to
As previously mentioned, in an alternative embodiment, the insert 408 is bonded to the cavity 404 (540). Any known bonding method and bonding agent may be implemented. For example, a bonding agent, such as any one of numerous glues, epoxies, silicone adhesives, or ceramic cements may be applied to the cavity walls 410, insert walls 412, or both. After the insert 408 and cavity 404 are aligned and brought into contact with one another, pressure is applied and maintained on the bonded area until the bonding agent has set. In an exemplary embodiment, after the insert 408 is inserted into the cavity 404, the top and bottom surfaces of the bulk absorber 106 panel around the insert 408 are machined down to create a uniform surface. In another exemplary embodiment, bonding may be employed in conjunction with mechanically locking the insert 408 into the cavity 404.
In the case where the repair process is performed on a noise suppression panel 100 having a back plate 102, a face plate 104, and bulk absorber 106, the face plate 104 first is removed (550). Then, the defect 402 is removed from the bulk absorber 106 without damaging the back plate 102. After the cavity 404 is prepared to receive the insert 408, the insert 408 is bonded at least to the back plate 102.
When the repair process is performed on a bulk absorber 106 panel during manufacture, after the bulk absorber 106 is repaired, a back plate 102 is bonded to the bulk absorber 106. Alternatively, a face plate 104 may be bonded to the bulk absorber 106 as well.
While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt to a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.
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|US8108979||Apr 24, 2007||Feb 7, 2012||United Technologies Corporation||Using a stiffener to repair a part for an aircraft engine|
|US8403624||Mar 31, 2008||Mar 26, 2013||General Electric Company||Composite containment casings having an integral fragment catcher|
|US8592024||May 26, 2006||Nov 26, 2013||United Technologies Corporation||Repair of perforated acoustic skins by reverse pin transfer molding|
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|EP1859923A1 *||May 17, 2007||Nov 28, 2007||United Technologies Corporation||Repair of composite materials|
|EP1972429A2 *||Mar 18, 2008||Sep 24, 2008||United Technologies Corporation||Repair of a composite sandwich structure having a perforated skin|
|EP1985538A2||Apr 22, 2008||Oct 29, 2008||United Technologies Corporation||Using a stiffener to repair a part for an aircraft engine.|
|EP2071137A2 *||Dec 3, 2008||Jun 17, 2009||General Electric Company||Method for repairing composite containment casings|
|EP2447470A1 *||Nov 2, 2010||May 2, 2012||Siemens Aktiengesellschaft||Component monitoring and method for operating a machine|
|WO2008104265A1 *||Feb 4, 2008||Sep 4, 2008||Eads Deutschland Gmbh||Method for repairing a component|
|WO2012059324A2 *||Oct 19, 2011||May 10, 2012||Siemens Aktiengesellschaft||Component testing and method for operating a machine|
|Cooperative Classification||F05D2230/80, F05D2220/50, F05D2260/96, F01D5/005, Y02T50/672, F02C7/045, B29C73/26, B29C73/06|
|European Classification||B29C73/26, B29C73/06, F02C7/045, F01D5/00B|
|Jul 29, 2004||AS||Assignment|
Owner name: HONEYWELL INTERNATIONAL, INC., NEW JERSEY
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:STEVENSON, JAMES F.;WILLIAMSON, ROGER B.;VINTILESCU, IONVIRGIL;AND OTHERS;REEL/FRAME:015658/0548
Effective date: 20040720