Abstract: An acoustic panel for sound attenuation employs a septumized cellular core sandwiched between a backsheet and a linear acoustic facesheet. The linear acoustic facesheet employs a linear material layer that impedes acoustic waves entering the core substantially linearly over a wide range of frequencies and sound of pressure levels.

Abstract: An acoustic structure that includes a septum having an acoustic opening which defines an open area that varies in response to changes in the velocity of noise-containing media passing through the acoustic opening. The septum includes a fixed portion and one or more movable flapper portions wherein the fixed portion and/or the flapper portion(s) include surfaces that define an acoustic opening through the septum. The acoustic opening has an open area which varies due to movement of the movable flapper(s) in response to changes in velocity of the noise-containing media that passes through the acoustic opening. The resulting septum has a relatively low non-linearity factor (NLF).

Abstract: The present disclosure provides a method of manufacturing a sound absorbing panel in which a reflective wall on one of faces of a set of sound absorbing cells. In particular, a passage on a portion of a thickness (E) of the set of sound absorbing cells is formed on an opposite face of the one of the faces, while the passage forming a main channel for a communication between sound absorbing cells and for a circulation of a de-icing fluid.

Abstract: Embodiments of thermal-acoustic sections for an aircraft for reducing noise along an acoustic path produced from an acoustic source are provided herein. The thermal-acoustic section comprises a first porous layer having a first characteristic acoustic impedance. A second porous layer is disposed adjacent to the first porous layer and has a second characteristic acoustic impedance that is greater than the first characteristic acoustic impedance. The thermal-acoustic section is configured to be positioned along the acoustic path such that at least a portion of the noise from the acoustic source is directed through the first porous layer to the second porous layer to promote absorption of the noise.

Abstract: The present disclosure describes use of filamentous algae to form insulating construction materials which provide thermal and noise insulation. Algae from the order Zygnematales, the Cladophorales, or the Ulotrichales can be dried and formed for use as insulating material. Algae mass can be combined into several layers, using a binder to attach the layers to each other. A composite material of algae mass and an additive can be used and form the body of insulation panels having honeycomb-shaped chambers, which are sealed by a foil that is laminated onto the body.

Abstract: A septum includes two septum plates and the edges of the septum plates are brought into contact at one of the junction edges of the septum plates. In particular, an angle (?) between one of the junction edges of the septum plates and one of the sides of the septum plates adjacent to the one of the junction edge is less than 90°.

Abstract: A method and apparatus comprising a composite panel and a number of structures to reduce noise radiation from the composite panel. The composite panel has a first face sheet, a second face sheet, and a core located between the first face sheet and the second face sheet. The number of structures is associated with the first face sheet. The number of structures has a mass with a configuration to reduce a speed of waves propagating in the composite panel such that noise radiating from the composite panel is reduced.

Abstract: A disclosed embodiment provides an acoustic panel having a composite laminate panel having a back sheet layer, a face sheet layer, and a core layer disposed therebetween. The core layer has one or more depressions at an interface between the core layer and the face sheet layer, with the face sheet having a generally uniform thickness across the composite laminate panel. A hole extends through the composite laminate panel at the depressions, and a bolt assembly extends through the hole such that it is countersunk.

Abstract: A turbojet engine nacelle includes at least one nacelle element having a wall delimiting a main flow channel. The flow channel has a variable flow passage section. The cross-sectional area of at least one first area of the channel is greater than that of at least one second area of the channel. The turbojet engine nacelle further includes at least one secondary flow conduit establishing a fluidic connection between the first area and the second area of the channel and is arranged parallel to the channel. The wall of the nacelle element is at least partly covered by an acoustic damping panel extending in said areas of the channel. The conduit passes through the acoustic damping panel in order to establish the secondary flow via the acoustic damping panel. The present invention can be used in the avionics field.

Abstract: An apparatus and method is disclosed for an improved acoustic panel comprising a sound absorbing member defined by a first and second face surface and a plurality of peripheral edges. A sound blocking member is defined by a first and second face surface and a plurality of peripheral edge. The first face surface of the sound blocking member is secured relative to the second face surface of the sound absorbing member for blocking the transmission of sound therethrough. In another embodiment, the first face surface of the sound blocking member is spaced relative to the second face surface of the sound absorbing member for decoupling the sound blocking member from the sound absorbing member.

Abstract: A sound-transmitting membrane (1) is provided that allows passage of sounds and prevents passage of foreign matters, the sound-transmitting membrane (1) including a supporting member (12) and a resin porous membrane (11) layered on the supporting member (12) and containing polytetrafluoroethylene as a main component. The supporting member (12) is a nonwoven fabric containing an elastomer. Since the supporting member (12) is a nonwoven fabric containing an elastomer, the insertion loss of the sound-transmitting membrane can be reduced for sounds of 3000 Hz.

Abstract: Thermally insulating septums are located internally within the cells of an acoustic honeycomb to regulate heat flow into the acoustic structure. The internally located insulating septums protect the honeycomb and acoustic septums located within the honeycomb cells from heat damage that might otherwise be caused by a heat source, such as the hot section of a jet engine. The internal thermal regulators are useful in combination with heat blankets or other thermal insulating structures to provide a reduction in size and/or weight of the insulating structure while still providing the same overall degree of thermal insulation for the acoustic honeycomb.

Abstract: A method for producing an acoustic treatment panel, including: assembling two plates, at least one of which is deformed so as to separate the plates locally in order to form cavities of a cellular structure between the two plates, said cavities being delimited by facets and partitions formed by at least one of the deformed plates, producing at least one opening on the facets of one of the two plates, and pressing an acoustically resistive plate against the surface of the cellular structure including the openings.

Abstract: A sound-transmitting membrane (1) is provided that allows passage of sounds and prevents passage of foreign matters, the sound-transmitting membrane (1) including a supporting member (12) and a resin porous membrane (11) layered on the supporting member (12) and containing polytetrafluoroethylene as a main component. The supporting member (12) is a nonwoven fabric containing an elastomer. Since the supporting member (12) is a nonwoven fabric containing an elastomer, the insertion loss of the sound-transmitting membrane can be reduced for sounds of 3000 Hz.

Abstract: A sound barrier comprises a substantially periodic array of structures disposed in a first medium having a first density, the structures being made of a second medium having a second density different from the first density, wherein one of the first and second media is a porous medium other than a porous metal, the porous medium having a porosity of at least about 0.02, and wherein the other of the first and second media is a viscoelastic or elastic medium.

Abstract: A method for making an acoustic structure that includes a honeycomb having cells in which septum caps are located. The septum caps are formed from sheets of flexible material that may be perforated before or after the material is inserted into the honeycomb. The flexible material is sufficiently flexible to allow folding into the shape of a septum cap. The flexible material is also sufficiently stiff to provide frictional engagement and locking of the septum cap to the honeycomb cell when the cap is inserted into the honeycomb during fabrication of the acoustic structure. An adhesive is applied to the septum caps after the caps have been inserted into the honeycomb cells to provide a permanent bond.

Abstract: The bandwidth or acoustical range of a nacelle or other type of acoustic structure is increased by acoustically coupling honeycomb cells together to form pairs of acoustic cells that have an effective acoustic or resonator length that is up to twice that of either acoustic cell taken alone.

Abstract: Thermally insulating septums are located internally within the cells of an acoustic honeycomb to regulate heat flow into the acoustic structure. The internally located insulating septums protect the honeycomb and acoustic septums located within the honeycomb cells from heat damage that might otherwise be caused by a heat source, such as the hot section of a jet engine. The internal thermal regulators are useful in combination with heat blankets or other thermal insulating structures to provide a reduction in size and/or weight of the insulating structure while still providing the same overall degree of thermal insulation for the acoustic honeycomb.

Abstract: An acoustic element has at least two board-shaped elements (1, 2). A dampening element (3), preferably a nonwoven element, is arranged between the two board-shaped elements (1, 2). The board-shaped elements (1, 2) exhibit bore holes (1c, 1d, 2c, 2d). The bore holes each exhibit a diameter of not more than 3 mm.

Abstract: A honeycomb structure dial includes cells in which septums are located to provide acoustic dampening. The cells are formed by at least our walls wherein at least two of the walls are substantially parallel to each other. The septums include warp fibers and weft fibers that are substantially perpendicular to each other. The septums are oriented in the honeycomb cells such that the weft fibers and/or warp fibers are substantially perpendicular to the parallel walls.

Abstract: A sound absorbing structure includes multiple sound absorbers. The sound absorbers are assembled together into a sound absorbing member. The sound absorbing member absorbs sound emitted from a sound source. Each of the sound absorbers is shaped like a hollow tube. Each of the sound absorbers has a hole extending in its axis direction.

Abstract: An acoustic absorber includes a wall provided with a plurality of apertures as well as a substantially non-perforated second wall, with the first wall and the second wall being spacedly arranged to one another, and at least one honeycomb structure being provided between the walls, with the honeycomb structure having a substantially cylindrical recess in at least one area, with a funnel element opening to the first and second walls being provided in the recess, and having a height greater than the distance of the walls, with the second wall being designed pot-like in the area of the funnel element.

Abstract: An acoustic-attenuating wall panel for a nacelle of a turbine engine may include a radiused portion. The radiused portion may include an airflow surface having a concave configuration and which may be exposed to an airflow passing through the nacelle. The radiused portion may include an acoustic attenuating section.

Abstract: Disclosed is an acoustic panel that includes a surface element including fibrous material. The acoustic panel also includes a back element that has a honeycomb structure and includes fibrous material, and an intermediate element that is arranged between the surface element and back element and has a porous structure.

Abstract: A sound attenuation mechanism made up of multiple substrate layers, including corrugated layers. The use of corrugation provides an inexpensive and manner of forming a plurality of highly effective acoustic attenuation channels throughout the mechanism. The multi-layered mechanism may be provided in a variety of modular forms and sizes which may be combined to form a low-cost, highly effective attenuation housing. For example, such a housing may be utilized to contain otherwise noisy large scale oilfield equipment such as coiled tubing engines. Additionally, where drainage from the housing is sought, a spiraled attenuation channel may be employed such that the effectiveness of the attenuation provided by the housing is not sacrificed.

Abstract: A panel-like/sheet-like finishing element (11) for covering floors and walls, for example in the renovation of old buildings, is provided with heat-insulating and sound-absorbing properties if its interior (15) is provided, between outer covering layers (12, 13), with channel-forming undulating supporting structures (16) filled with high-density coarse granules (21). The supporting structures (16) are connected to the covering layers (12, 13) along the vertex lines (17) so as to provide wet-strength action, and the interior (15), between these covering layers, is sealed by enclosing edging strips (19) to provide wet-strength action, with the simultaneous inclusion of moisture-tight, but vapour-permeable, supporting layers (20) on covering layers (12, 13). If this finishing element (11) is mounted vertically, the granule-filled channels (14) run horizontally.

Abstract: A method and apparatus for reducing sound. A layer of material has holes extending from a first side of the layer of material to a second side of the layer of material. The holes are configured to provide a desired level of acoustic resistance to sound traveling through the layer of material. The layer of material is configured to be mounted to a platform.

Abstract: The bandwidth or acoustical range of a nacelle or other type of acoustic structure is increased by acoustically coupling honeycomb cells together to form pairs of acoustic cells that have an effective acoustic or resonator length that is up to twice that of either acoustic cell taken alone.

Abstract: The invention relates to an acoustic skin (22) for an aircraft nacelle acoustic panel, said skin including a plurality of layers (105, 106) stacked with composite planar bands (102) that are each directed by the direction-defining longitudinal axis (107) thereof, the longitudinal axes (107) of the bands (102) of a single layer (105, 106) being parallel therebetween, said bands (102) of said single layer (105, 106) being spaced from each other so as to have acoustic openings within the acoustic skin. The invention relates to a panel including such a skin, to a method for manufacturing said skin, and to a drape-forming head for implementing the method.

Abstract: Honeycomb sections are bonded together with seams made up of an adhesive that is carried by a linked-segment seam support. The seams are particularly useful for splicing together curved honeycomb sections that contain acoustic septum. The curved acoustic honeycomb sections are spliced or seamed together to form engine nacelles and other acoustic damping structures.

Abstract: A composite component includes a honeycomb, a skin bonded to the honeycomb, a repair section bonded adjacent to the skin, and at least one cover secured on at least a portion of the repair section to resist peeling of the repair section.

Abstract: The invention relates to an acoustic panel (20) for an ejector nozzle (10) comprising the following main components: an external skin (22) containing acoustic holes (29); an internal skin (23); an acoustic structure (21) comprising alveolar-core cells (27) between the internal skin (23) and the external skin (22). At least one main component selected from the external skin (22), the internal skin (23) and the acoustic structure (21) is formed by a composite material and the acoustic structure (21) is held in contact with either or both of the internal (23) and external (22) skins by compression by elastic means and/or by fixing by mechanical fixing means (24). The invention also relates to an injector nozzle (10) and a nacelle (1) comprising such an acoustic panel (20).

Abstract: The present disclosure relates to a method for repairing a portion of an acoustic panel for a nacelle of an aircraft turbojet engine. The panel includes an acoustic skin in which a plurality of acoustic holes are drilled, a solid skin, and a cellular acoustic structure. The cellular acoustic structure, being arranged between the acoustic skin and the solid skin, has a plurality of cells, each of which has one or more drainage openings arranged in one or more of the walls forming each cell. The method includes a step of: defining a part of the acoustic panel to be cut; forming a cutting area closed by the acoustic skin; injecting a resin through the acoustic holes; positioning a replacement cellular acoustic structure in the cutting area and on the acoustic skin; forming a solid replacement skin on the replacement cellular acoustic structure.

Abstract: An acoustic splash shield that combines sound damping and sound absorption is provided. The splash shield can have a first solid thermoplastic layer, an optional second porous layer extending across the first solid layer and a third hollow-shaped and/or corrugated-shaped thermoplastic layer extending across the second porous layer. The first, optional second, and third layers are operatively arranged to form an integral component with the second porous layer sandwiched between the first and third layers in order to provide a sound damping and sound absorbing splash shield having a pair of non-porous outer layers. The third hollow-shape and/or corrugated-shaped thermoplastic layer forms a plurality of hollow rectangular-shaped cavities against the first solid thermoplastic layer and the cavities are shaped in order to provide a plurality of hollow sound absorbing cavities that absorb sound wave frequencies within a desired range.

Abstract: An acoustic structure that includes a septum having an acoustic opening which defines an open area that varies in response to changes in the velocity of noise-containing media passing through the acoustic opening. The septum includes a fixed portion and one or more movable flapper portions wherein the fixed portion and/or the flapper portion(s) include surfaces that define an acoustic opening through the septum. The acoustic opening has an open area which varies due to movement of the movable flapper(s) in response to changes in velocity of the noise-containing media that passes through the acoustic opening. The resulting septum has a relatively low non-linearity factor (NLF).

Abstract: A honeycomb structure that includes cells in which septums are located to provide acoustic dampening. The cells are formed by at least four walls wherein at least two of the walls are substantially parallel to each other. The septums include warp fibers and weft fibers that are substantially perpendicular to each other. The septums are oriented in the honeycomb cells such that the weft fibers and/or warp fibers are substantially perpendicular to the parallel walls.

Abstract: The invention is an acoustic liner for attenuating noise in rotating machinery. The acoustic liner may include a plurality of cells coupled together to form an annular cell matrix, the plurality of cells being made of a non-metallic material, for example, plastics, polymers, thermoplastics, or thermosets. Each cell of the acoustic liner may be hexagonally-shaped such that the annular cell matrix forms a honeycomb structure.

Abstract: A method for repairing a sound attenuation panel is disclosed. The panel includes a structuring skin in metal material, a resistive layer in metal material and a honeycomb structure as acoustic absorption material directly added onto the structuring skin and resistive layer. The method includes a step in which one reinforcing pin is inserted into the thickness of the attenuation panel and a step in which the reinforcing pin is secured by welding in a controlled atmosphere to the structuring skin and resistive layer respectively.

Abstract: The present invention relates to a gas-turbine exhaust cone having an outer wall, which is provided with a plurality of recesses, a honeycomb-structured layer, which is arranged on the inside of the outer wall and extends along the inside of the outer wall, an inner wall, which extends substantially parallel to the outer wall and is connected to the honeycomb structure, and at least one annular chamber, which adjoins the inner wall and is centered relative to a central axis, with the inner wall being provided with passage recesses 33-connecting the area of the honeycomb structure to the annular chamber.

Abstract: The present invention relates to a method for manufacturing a body provided with a honeycomb structure, which body is designed preferably axis-symmetrical, with sheet-metal parts being provided with a wave-like structuring by means of a forming process and formed to ring elements, with the sheet-metal parts being shaped and designed in a substantially identical way as regards their structuring, with adjacent sheet-metal parts being arranged offset to one another and then joined together to form the honeycomb structure.

Abstract: The bandwidth or acoustical range of a nacelle or other type of acoustic structure is increased by acoustically coupling honeycomb cells together to form pairs of acoustic cells that have an effective acoustic or resonator length that is up to twice that of either acoustic cell taken alone.

Abstract: The invention provides a device for acoustical treatment of the noise emitted by a bypass turbojet comprising a primary cowl having in an outer surface an inner annular acoustic treatment panel and a secondary cowl including in an inner surface an outer annular acoustic treatment panel arranged facing the inner panel. The inner and outer panels include respective central panel portions facing each other and extending axially over a common predetermined length, the length of the central panel portions lying in the range one-fifth to four-fifths of the total length of the panels, and the ratio between the acoustic resistances of the central panel portions being not less than 2.

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: The present disclosure relates to a method for repairing a portion of an acoustic panel for a nacelle of an aircraft turbojet engine. The panel includes an acoustic skin in which a plurality of acoustic holes are drilled, a solid skin, and a cellular acoustic structure. The cellular acoustic structure, being arranged between the acoustic skin and the solid skin, has a plurality of cells, each of which has one or more drainage openings arranged in one or more of the walls forming each cell. The method includes a step of: defining a part of the acoustic panel to be cut; forming a cutting area closed by the acoustic skin; injecting a resin through the acoustic holes; positioning a replacement cellular acoustic structure in the cutting area and on the acoustic skin; forming a solid replacement skin on the replacement cellular acoustic structure.

Abstract: A partition panel improves sound insulation performance and optimizes a reverberation time. The partition panel has sound absorption and insulation functions, and has a front plate having a perforated section with a plurality of through-holes and an entirely-continuous peripheral edge portion located outside the perforated section. An entirely-continuous back plate is disposed on a side opposite to a sound source across the front plate. An inner perforated plate is disposed between the perforated section of the front plate and the back plate. A front-side honeycomb core is interposed between the perforated section and the inner perforated plate, a back-side honeycomb core is interposed between the back plate and the inner perforated plate and a peripheral honeycomb core is interposed between the peripheral edge portion of the front plate and a region of the back plate opposed to the peripheral edge portion.

Abstract: Sound absorbency is imparted on a panel, which has increased strength and rigidity, by laminating a foam resin that is not originally permeable and does not absorb sound, and surface sheets that are not originally permeable and do not absorb sound. A sound absorption panel 1, obtained by laminating a foam resin 20 comprising closed cells and aluminum alloy sheets 10 (metal sheets), has a plurality of holes 30 formed therein, which penetrate the foam resin 20 and the aluminum alloy sheets 10 in the thickness direction. The holes 30 are formed by forcing a needle 40 (hole-forming means) through the foam resin 20 and the aluminum alloy sheets 10.

Abstract: A surface cooler is provided and includes an oil layer through which oil flows, fins extending into an air flow pathway and being disposed at a first side of the oil layer in heat transfer communication with the oil, an acoustic lining to reduce noise present in or transmitted by the air flow pathway, which is disposed at a second side of the oil layer opposite the first side and noise transfer tubes extending through the oil layer to transfer the noise present in or transmitted by the air flow pathway to the acoustic lining.

Abstract: The invention provides an enclosure, in particular, an acoustic enclosure, for thermal equipment, for example a gas turbine or a gas turbine auxiliary module. The invention also provides a method of constructing such an enclosure.

Abstract: An aircraft cabin plate absorber includes a supporting panel, a cover panel and an intermediate layer which is arranged between the supporting panel and the cover panel. The cover panel includes a cover layer which is visible from the cabin space, and is arranged on the supporting panel on the side facing the sound inside the cabin space. The cover panel is fastened to the supporting panel by the intermediate layer, and comprises at least one connecting region, in which it is connected to the supporting panel, and at least one absorption region, in which it is arranged so as to oscillate with respect to the supporting panel. The panel is optimized in term of space requirement and weight for use in aircraft and has improved sound absorption properties.

Abstract: A disclosed embodiment provides an acoustic panel having a composite laminate panel having a back sheet layer, a face sheet layer, and a core layer disposed therebetween. The core layer has one or more depressions at an interface between the core layer and the face sheet layer, with the face sheet having a generally uniform thickness across the composite laminate panel. A hole extends through the composite laminate panel at the depressions, and a bolt assembly extends through the hole such that it is countersunk.