Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: Systems and methods for noise suppression are disclosed herein. In one embodiment, an acoustic structure has a core that includes a plurality of cells. Each of the plurality of cells includes one or more engaging structures for positioning a septum relative to the cell. The acoustic structure further includes a plurality of septums positioned relative to the plurality of cells.

Abstract: The invention relates to a method for making an acoustic absorption panel in particular for the nacelle of an aircraft engine, the panel being of the type comprising a cellular core covered on one side with a so-called outer air-permissive skin and on the other side with a so-called inner perforated skin, the cellular core being formed by the edge-to-edge junction of a plurality of blocks with a cellular core (B1, B2). The method comprises the following steps: a) before the edge-to-edge junction of blocks with a cellular core (B1, B2), opening the cells (A1, A2) located on the edges of the blocks to be joined; and b) edge-to-edge dry joining the blocks (B1, B2) so that the open cells (A1, A2) engage into one another.

Abstract: An acoustic treatment device for an internal primary ejection duct from a turbojet pod, including an upstream zone and a downstream zone relative to an airflow direction in the primary ejection duct, the upstream and downstream zones being located on each side of a separating wall with a first face on the side of the upstream side and a second face on the side of the downstream side. The separating wall is a micro-porous wall and the face of the separating wall located on the side of the downstream side is covered by a honeycomb structure to attenuate high frequency acoustic waves. Such a device may find application to treatment of combustion and turbine noises.

Abstract: The invention includes a joint assembly for connecting first and second longitudinal edges of portions of an acoustic barrel or panel having an open cell core, a perforated inner skin, and an outer skin. The joint assembly includes at least one strip covering a plurality of openings in walls of cells along the first and second longitudinal edges. The strip is separate from the inner and outer skins. A plate includes a first portion connected to the outer skin proximate to the first longitudinal edge, and a second portion connected to the outer skin proximate to the second longitudinal edge.

Abstract: The aim of the invention is to improve acoustic insulation panels of the prior art by proposing a rigid, light panel, the acoustical absorption performance of which is improved thanks to the use of a grid the structure of which enables the same to contribute to the noise absorption function. To this end, the present invention relates to an acoustic insulation panel including two facing panels (2, 4), separated by a solid structure (6) that is substantially planar and has two surfaces (7b, 7c) that are substantially planar and parallel, each of which are rigidly connected to a facing panel, said structure (6) including through-holes (6a) that form a mesh, such that the meshed structure contributes to the noise absorption function.

Abstract: A panel for acoustic treatment connected to a surface of an aircraft, includes—from the outside to the inside—an acoustically resistive porous layer, at least one alveolar structure, and a reflective or impermeable layer, whereby the acoustically resistive porous layer includes—at the outside surface that can be in contact with the aerodynamic flows—one sheet or piece of sheet metal including open zones (14) that allow sound waves to pass and filled zones (16) that do not allow sound waves to pass, characterized in that the sheet or piece of sheet metal of the acoustically resistive layer includes sets of microperforations (18), whereby each set of microperforations forms an open zone (14), the sets of microperforations being separated from one another by at least one series of bands separated by filled zones (16).

Abstract: An acoustic assembly for a fan casing of a turbofan engine is made up from acoustic liner panel components which each comprise a body and a backing sheet. The body is an integral injection moulding that generally includes an acoustic structure, a perforated sheet and fastening portions. Adjacent panel components engage each other at non-linear circumferential edges which generally includes lugs on one of the components which are received in recesses of the other component. The lugs are defined by following cell walls over a convoluted path along the circumferential edge.

Abstract: An acoustical building panel and method of manufacturing it are disclosed. Embodiments of the panel include a porous nonwoven scrim, a coating deposited on the scrim, a base mat, and an adhesive deposited on either the base mat or the scrim in a discrete form such as in droplets. Embodiments of the method of manufacture include steps of perforating the base mat, applying the adhesive to the base mat in the discrete form, laminating the scrim onto the base mat, and applying the coating to the scrim surface.

Abstract: An acoustic panel includes a reflective layer, at least one alveolar structure, and an acoustically resistive structure forming an aerodynamic surface of an aircraft on the surface of which at least one acoustic wave propagates along an axis of propagation (24), whereby at least one of the characteristics of the acoustic panel influences the impedance of the panel that varies along the axis of propagation of the at least one acoustic wave, characterized in that it includes at least one first zone A with a constant acoustic impedance that is juxtaposed along the axis of propagation of the at least one acoustic wave at a zone C at which at least one characteristic of the acoustic panel that influences the impedance gradually varies along the axis of propagation of the at least one acoustic wave, whereby the characteristic has a value without sudden variations from one zone to the next.

Abstract: A coating for acoustic treatment relative to an aircraft's surface, in particular a leading edge such as an air intake of an aircraft nacelle, includes an acoustically resistive layer, at least one alveolar structure (30), and a reflective layer. The alveolar structure (30) includes a number of tubes that empty out, on the one hand, at a first imaginary surface (34), and, on the other hand, at a second imaginary surface (36). The alveolar structure (30) includes cut-outs or openings (38) made at the side walls of certain tubes that make it possible to link adjacent tubes so as to create a network of communicating tubes that isolate at least one tube or a group of non-communicating tubes, whereby at least one of the communicating tubes is connected to at least one hot gas intake (40).

Abstract: A method of restoring a section of a composite includes the steps of removing an undesirable section of a composite and securing a repair section in the location of the removed undesirable section. One or more covers are secured on at least a portion the repair section to prevent or resist peeling of the repair section.

Abstract: A linear acoustic liner for an aircraft includes a cellular core having a first surface and an opposed second surface. A substantially imperforate back skin covers the first surface, and a perforate face skin covers the second surface of the core. The perforate face skin includes an outer face skin layer having a first plurality of spaced openings, an inner face skin layer having a second plurality of spaced openings, and a porous layer disposed between the outer face skin layer and the inner face skin layer. Each of the first plurality of spaced openings are substantially aligned with one of the second plurality of spaced openings.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: An apparatus comprises a core having a first surface configured for attachment to a surface of a structure, a face sheet located over a second surface of the core, a number of cavities within an interior of the core, and a number of ports for the number of cavities. The number of ports provides communication between the number of cavities within the interior of the core and the exterior of the core. The number of cavities and the number of ports are configured to reduce noise traveling through the core.

Abstract: A method of restoring a section of a composite having a honeycomb bonded to a perforated skin includes the steps of separating a first honeycomb from the perforated skin to expose a portion of the perforated skin, inserting pins through perforations in the perforated skin, extending the pins through a repair material, attaching the repair material to the exposed portion of the perforated skin, and attaching a second honeycomb to the repair material. The method may include removing material from the exposed portion of the perforated skin, prior to inserting pins through the perforations, to create a more even bonding surface for attaching the repair material.

Abstract: An engine assembly, an acoustical liner and an associated fabrication method are provided to address fan blade flutter and fan noise control simultaneously within the same liner area. Fan blade flutter is therefore controlled without necessarily increasing the weight of the engine, impairing the structural integrity of the engine, or increasing the noise generated by the engine. The acoustical liner may have additional acoustical degrees of freedom which permit these seemingly competing concerns to be addressed in a complementary manner. The acoustical liner may include inner and outer barrels with the inner barrel having a perforated face sheet, a perforated back skin and a core disposed between the perforated face sheet and the back skin. The fluid communication between the core and the space between the inner and outer barrels provides additional acoustical degrees of freedom which may be utilized to reduce fan blade flutter while concurrently limiting fan blade noise.

Abstract: The invention includes a joint assembly for connecting first and second longitudinal edges of portions of an acoustic barrel or panel having an open cell core, a perforated inner skin, and an outer skin. The joint assembly includes at least one strip covering a plurality of openings in walls of cells along the first and second longitudinal edges. The strip is separate from the inner and outer skins. A plate includes a first portion connected to the outer skin proximate to the first longitudinal edge, and a second portion connected to the outer skin proximate to the second longitudinal edge.

Abstract: An inlet of an aircraft nacelle having an acoustic barrel configured to reduce engine fan flutter by attenuating various frequencies. The acoustic barrel may comprise an acoustic panel of a honeycomb configuration sandwiched between a first back sheet and a face sheet and extending from a forward bulkhead to an aft bulkhead of the inlet. The acoustic barrel may further comprise a deep liner section bonded to and sandwiched between the first back sheet and a second back sheet. The deep liner section may have a narrower width than the acoustic panel and may be located proximate the aft bulkhead. The sections of the first back sheet, the face sheet, and a septum of the acoustic panel may be perforated and may contain additional holes formed in portions aligned radially inward of the deep liner section.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: A sound absorption element for means of transport, in particular for aircraft, comprising at least one sound absorption panel arranged on a base panel with the base panel comprising a multitude of recesses, in particular a hole grid or the like, for the transmission of sound. According to the invention, the sound absorption panels are each framed by a frame, wherein on the at least one frame at least in some sections a transition profile, in particular to prevent fatigue fractures due to stepwise changes of rigidity between the at least one frame and the base panel is arranged. Due to the base panel comprising a multitude of recesses, in particular comprising a hole grid, in connection with the sound absorption panels an air-permeable sound absorption element can be achieved.

Abstract: An assembly is provided for reducing the noise that is generated in the heating gas zone by turbofan engines. The assembly consists of an acoustically absorbent cladding in the heating gas flow channel of the turbofan engine. The cladding includes a plurality of neighboring cavities, into each of which four horns extends. The mouths of the horns are fixed to a perforated cover sheet. The cover sheet forms one wall of the heating gas flow channel.

Abstract: An acoustic inner barrel for an aircraft engine nacelle inlet is constructed from a composite material and is formed as a single, 360-degree annular segment. The barrel includes an inner skin, an outer skin, a cellular core disposed between the inner skin and the outer skin, and at least one crack and delamination stopper extending radially from the inner skin to the outer skin.

Abstract: An absorbent structure for reducing the propagation of soundwaves emitted by noisy devices such as rotors or motors, the structure includes a rigid partition (1), at least one porous wall (4), and separator elements (2) for placing the porous wall (4) at a determined distance from the rigid partition (1), defining cavities (3) of a height h1 between the porous wall (4) and the rigid partition (1), the height h1 being determined to obtain maximum absorption of a given frequency of the emitted soundwaves, wherein includes additional absorption elements for obtaining maximum absorption of at least one additional frequency of the emitted soundwave.

Abstract: An aircraft cabin panel for sound absorption, with a sandwich construction, comprising a core layer that comprises a plurality of tube-like or honeycomb-like cells that extend in an open manner across the thickness of the core layer and that are separated from each other by cell walls and that are uniform in design. A first cover layer faces away from the sound field, as well as a second cover layer that faces towards the sound field and that comprises a plurality of perforation holes and adjacent cells are interconnected by way of apertures in the cell walls. The perforation of the second cover layer comprises a distance (b) between holes, which distance exceeds the opening width (c) of the cells of the core layer, wherein the first cover layer is closed and wherein the cell walls comprise a perforation so that they are acoustically transparent in the direction parallel to the cover layers.

Abstract: An acoustic, noise-attenuating panel for an aircraft engine nacelle inlet. The panel includes at least three layers: (a) a perforated film; (b) a sound attenuating core; and (c) a structural layer. The structural layer has through-holes adapted for receiving fasteners that are configured to engage structure of an engine nacelle. The structural layer is fabricated, at least at its ends, of a material sufficiently strong so that when fasteners are engaged in the through-holes in the layer's ends, the fasteners retain the acoustic panel in a nacelle inlet under conditions of use. Alternatively, or in addition, the structural layer ends may be reinforced at the through-holes with reinforcing strips.

Abstract: In order to provide sound absorbing structure capable of reducing the noise of electronic equipment while maintaining the cooling capability of the electronic equipment, there is provided sound absorbing structure in which a plurality of penetrating openings are provided by arranging a plurality of acoustic materials having a predetermined shape at predetermined intervals in a flow channel of cooling fluid from a blower, and the plurality of acoustic materials are arranged so that the sound vertically incident on a penetrating plane of the penetrating openings from the blower does not directly go out of the electronic equipment.

Abstract: It is an object of the present invention to provide a floor silencer that has good transport efficiency due to an ability to be transported in a flat state, and can be assembled to a floor panel of a vehicle by folding along a band-like concave portion. The floor silencer is used with a first surface side in contact with a floor carpet, and a second surface side in contact with the floor panel of the vehicle. The floor silencer also has the band-like concave portion and can be folded along the band-like concave portion. The floor silencer is transported in a flat state and not folded during transport, and is used folded along the band-like concave portion during assembly.

Abstract: A speaker enclosure having a substantially seamless rigid outer skin, a middle sound absorbing layer, and a substantially seamless inner skin results in a lightweight speaker having sound absorbing characteristics. The speaker enclosure is comprised of two basic parts, a box section and a baffle section where each of these sections include a rigid outer skin, the middle sound absorbing layer and a seamless inner skin and are made according to the same method. The outer skin is formed from a layer of sheet molding compound, the middle sound absorbing layer includes pieces of honeycomb material, and the inner skin is formed from a layer of sheet molding compound. The layers of material are placed into a mold and then cured through vacuum bagging and heating thereby producing a strong, lightweight speaker enclosure made of materials which attenuate the transmission and retransmission of errant sound waves in the enclosure thereby reducing distortion of the sound signal produced by the speaker.

Abstract: The invention is directed to a method for manufacturing a sandwich like constructed light weight sheet with sound absorption characteristics, by which an acoustically absorbing cover layer, a substantially grid shape configured first intermediate layer and a bottom layer are bound together, wherein the light weight sheet has a defined surface.

Abstract: An acoustic treatment device for an internal primary ejection duct from a turbojet pod, including an upstream zone and a downstream zone relative to an airflow direction in the primary ejection duct, the upstream and downstream zones being located on each side of a separating wall with a first face on the side of the upstream side and a second face on the side of the downstream side. The separating wall is a micro-porous wall and the face of the separating wall located on the side of the downstream side is covered by a honeycomb structure to attenuate high frequency acoustic waves. Such a device may find application to treatment of combustion and turbine noises.

Abstract: Ballistic resistant composites and articles formed therefrom for use in airplanes and other vehicles which meets particular structural, impact and ballistic requirements. An aerospace-specification grade honeycomb is positioned between panels comprising non-woven ballistic resistant fibrous layers, and optionally one or more fire resistant layers. The composites and the articles formed therefrom have superior structural, impact, fire resistance and ballistic performance at a light weight.

Abstract: In order to provide a sound-absorbing panel and a production method of the same which has excellent freedom of design and have small differences in the maximum sound-absorbing coefficients among products, a sound-absorbing panel is adopted which is characterized by a panel main body which is constituted by arranging both a porous veneer of 0.02-0.5 mm thickness with multiple pierced apertures of 0.1 mm or smaller aperture diameters or 0.2 mm or smaller aperture diameters and a porous sound-absorbing base material set at a backside of the porous veneer so as to be overlapped, and is characterized by having a value of airflow resistance in a range of 0.1-1.0 Pa.

Abstract: A wall element for the sound-insulating interior lining of a transport device, comprising at least one sandwich element, at least one insulation package and at least one absorber plane element. The sandwich element comprises at least one core layer, a first cover layer and a second cover layer, wherein the first cover layer and the second cover layer are each arranged on one side of the core layer. At least the first or the second cover layer is a microperforated layer; the sandwich element possesses a shear rigidity that is adjusted in such a way that the sandwich element comprises one or several coincidence boundary frequencies that are determined by the shear rigidity, which coincidence boundary frequencies are outside the frequency range that dominates the noise in the interior of the cabin; and the shear rigidity of the sandwich element at the same time is sufficient for said sandwich element to be used as an interior lining.

Abstract: A trim panel for an aircraft interior includes a first sound attenuating layer, a structural layer and a second sound attenuating layer. The structural layer is coupled to the exterior sound attenuating layer, and has an exterior side and an opposite interior side. The structural layer defines a plurality of passages that open to both the exterior side and the interior side so as to minimize radiation of noise due to a hydrodynamic shortcut created by each of the passages across the structural layer. The second sound attenuating layer is coupled to the structural layer and has a high sound absorption characteristic. The second sound attenuating layer is configured to be disposed adjacent to the aircraft interior.

Abstract: An aircraft cabin panel for sound absorption, with a core layer that comprises a plurality of cells that extend in an open manner across the thickness of the core layer and that are separated from each other by cell walls, and with a first cover layer that faces away from the sound field, as well as a second cover layer that faces towards the sound field and that comprises a plurality of perforation holes. The second cover layer is multi-layered and apart from a layer with the perforation also comprises a second layer that acts as a flow resistance device. The second layer is arranged on the outside, and visually closes off the perforation, and the outer layer comprises an air-permeable woven fabric.

Abstract: An aircraft cabin panel for sound absorption, with a sandwich construction, comprising a core layer that comprises a plurality of tube-like or honeycomb-like cells that extend in an open manner across the thickness of the core layer and that are separated from each other by cell walls and that are uniform in design. A first cover layer faces away from the sound field, as well as a second cover layer that faces towards the sound field and that comprises a plurality of perforation holes and adjacent cells are interconnected by way of apertures in the cell walls. The perforation of the second cover layer comprises a distance (b) between holes, which distance exceeds the opening width (c) of the cells of the core layer, wherein the first cover layer is closed and wherein the cell walls comprise a perforation so that they are acoustically transparent in the direction parallel to the cover layers.

Abstract: An example liner assembly includes a backing plate that supports a cellular structure covered by a perforated face sheet including a plurality of openings. Each of the plurality of openings is of a size determined to provide desired acoustic performance.

Abstract: A soundproofing panel having a core sandwiched between a solid wall and a porous wall. The core being connected to the walls and having partitions extending in the thickness direction between the two walls so as to form cells. Each cell containing at least one sound energy dissipating layer constituted by hollow spherical beads having mutually contacting walls that are porous and micro-perforated, and being held in position in the thickness direction between the two walls by nets that are secured to the partitions.

Abstract: The present invention relates to a combination acoustic diffuser and absorber and method of production thereof. The diffuser has an acoustically reflective surface that may be made by the vacuum forming of pliable sheet material in conformity with a shaped template and the subsequent fixing of the resulting shape of said material, and which surface includes a plurality of wells, the depths of which wells may be determined by number theory sequences. The absorber may include one or more tunable Helmholtz resonators which may be attached to the rear face of the diffusing surface. The combination acoustic diffuser and absorber may be optimized in its function and construction for use in a typical residential application. A kit may also be provided that comprises a diffuser, absorbers, mounting hardware, and assembly and adjustment instructions.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: A sealing system for sealing a component (102) within an electronic device (100) is provided. The system includes one or more apertures (206) within an internal housing (202). Further the system includes an adhesive (602), adhered on a first surface to a ledge (502) and bottom perimeter surface 402 of the component. Furthermore, the system includes an external housing (204). The external housing presses the perimeter of the component onto the ledge.

Abstract: An apparatus and method is provided for attenuating aerospace engine noise and unsteady pressure fluctuations associated with high velocity exhaust flows. The apparatus and method reduce acoustic fatigue damage to aerospace vehicles that may be caused by the reflection of exhaust energy from landing and/or launch platforms. The apparatus includes a passive treatment area associated with the platform operable for reducing the magnitude of the reflected sound waves and unsteady pressure fluctuations from the high velocity exhaust mass flow exiting from the engine. The passive treatment area may include a layer of sound absorptive material, at least one set of roughness elements for disrupting high velocity flow structures. A protective cover may be positioned over the passive treatment area for permitting exhaust flow to pass therethrough while still providing adequate structure to support the weight of the aerospace vehicle.

Abstract: There is provided an acoustic structure and a method of manufacturing such acoustic structure. The acoustic structure comprises at least one uncured facesheet ply defining a plurality of perforations, an adhesive that includes a corresponding plurality of perforations, and a honeycomb core portion adhered to the facesheet ply by the adhesive. The acoustic structure undergoes a single curing process, advantageously an autoclave curing process, to cure the entire acoustic structure. By adhering at least one uncured facesheet ply to the honeycomb core portion, the curing process is capable of curing both the facesheet ply and the adhesive with a single curing process. The single curing process accordingly obviates additional process steps and a sacrificial adhesive layer typically used in other acoustic structures.

Abstract: A sound attenuation panel includes a resistive layer with a reinforced structural component, comprising at least a honeycomb structure (1) flanked, on one side, with a resistive layer (2) consisting of at least a porous layer (2b) and of at least a perforated structural layer (2a), and, on the other side, with a layer forming a total reflector (3). The structural layer (2a) is perforated with non-circular holes (4) having each its largest dimension and its smallest dimension along respectively two perpendicular axes. The panel is particularly applicable to pods for aeroplane jet engines.

Abstract: An acoustic absorbing device includes a housing having a chamber formed by an outer peripheral wall and a bottom wall, a hood engaged into the housing, an absorbing member engaged into the hood, and a silencer engaged into the absorbing member, the silencer and the absorbing member may be selectively attached to the hood or may be easily replaced with the other ones or new or different ones according to different environment. The silencer may include an outer cap extended into or out of the absorbing member. The housing includes one or more couplers for selectively coupling the housing to the other coupling or supporting members.

Abstract: A perforated soundproof structure is formed by oppositely arranging an external plate 1 and an internal plate 2 having a number of through-holes 2a. The board thickness, hole diameter and open area ratio of the internal plate 2 are set to satisfy design conditions to give rise to a viscous effect in the air passing through the through-holes 2a, and the design conditions are set so that the frequency bandwidth to attain an absorption coefficient of 0.3 or more is 10% or more of the resonance frequency.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: An acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of acoustic material and include a resonator portion and a flange portion. The flange portion has an anchoring surface that provides frictional engagement of the septum caps to the honeycomb cells when the caps are inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the anchoring surface of the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: The present invention provides a composite muffler for use with an auxiliary power unit. The composite muffler comprises a composite outer can, an annular baffle, an acoustic liner, and a thermal barrier. The composite outer can is disposed substantially symmetrically about a longitudinal axis and has an inner peripheral surface defining a cavity. The annular baffle is disposed within the composite outer can cavity, has an opening formed therein, and extends radially outwardly from the opening toward the composite outer can inner peripheral surface. The acoustic liner extends through the annular baffle opening. The thermal barrier is coupled between the annular baffle and the outer can inner peripheral surface.