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: An improved exhaust fan housing, and exhaust fan assembly so characterized, is generally provided. The exhaust fan housing includes a first cylindrical or conical element, a second cylindrical element interior of the first cylindrical element, and a plurality of hollow vanes traversing an annular fluid passage chamber delimited thereby and uniting the first and second cylindrical elements. A central drive chamber, delimited by the second cylindrical element, is in fluid communication with ambient air exterior of the first cylindrical element via the hollow vanes. Each hollow vane is characterized by spaced apart wall segments which unitingly terminate so as to delimit a leading edge for each hollow vane, each of the spaced apart wall segments having a free end or a closed end delimiting first and second trailing edges for the hollow vanes.

Abstract: A fence (1) comprising a series of fence parts comprising a first and second pole (4,5,40,43,45) and a first and second opposing wall (2,3) extending between the first and second pole (4,5,40,43,45), thereby defining an interior space (9) for containing a sound suppressing material. The walls (2,3) comprises at least one profile (6,22-24,33-36) having opposing free ends (7,8) for engaging the first and second pole (4,5,40,43,45). Each profile (6,22-24,33-36) has a first section (10,25-27) facing a free end of the poles (4,5,40,43,45), the first section (10,25-27) extends into a second section (11,28-30) that is closer to the interior space (9) than the first section (10,25-27), each pole (4,5,40,43,45) comprises at least one assembling track (16) extending along the length of the pole (4,5,40,43,45), and the at least one assembling track (16) is configured to accommodate at least a part of the free (7,8) end of the profiles (6,22-24,33-36).

Abstract: A soundproofing plate comprising a substrate having a substrate having at least one through hole formed therein; and a soundproofing device mounted on the through hole of the substrate. The soundproofing device has a multiplex structure having at least a first structure and a second structure nested therein. The first structure comprises a through hole (“first air passage hole”) disposed in the center and communicating with the through hole of the substrate, and a first sound collecting portion disposed at both ends or one end and having a larger size than the aperture area of the first air passage hole, and being arranged so as to reflect incident noise. The second structure comprises a through hole (“second air passage hole”) disposed in the center and communicating with the through hole of the substrate, and a second sound collecting portion disposed at both ends or one end and having a larger size than the aperture area of the second air passage hole, and being arranged so as to reflect incident noise.

Abstract: Air bubbles may be used to reduce radiated underwater noise. Two modalities of sound attenuation by air bubbles were shown to provide a reduction in radiated sound: bubble acoustic resonance damping and acoustic impedance mismatching. The bubbles used for acoustic resonance damping were manifested using gas-filled containers coupled to a support, and the acoustic impedance mismatching bubbles were created using a cloud of freely-rising bubbles, which were both used to surround an underwater sound source.

Abstract: Acoustically damped component for a vehicle, an engine, a transmission or a vehicle trim panel, includes a flat basic body provided on at least one side with a rib structure. The ribs of the rib structure form chambers which are arranged irregularly on at least one region of the component, which has a resonant frequency of from 200 to 1000 Hz. The chambers are configured irregularly in such a way that chambers of the component have different dimensioning and/or geometry in comparison with adjoining chambers, such that emitted airborne sound can be reduced and/or eradicated. A response to a transient excitation of at least two part areas of that surface of the component which is provided with the chambers having a correlation of from 0.5 to 0.85, preferably of from 0.6 to 0.7.

Abstract: Transparent panel of acrylic glass (PMMA) having internal reinforcement elements for securing fragments of the acrylic glass formed upon an impact with a foreign body. The reinforcement elements are embedded interspersed within the panel and spaced apart in parallel longitudinally. The reinforcement elements include rigid cables and elastic cables. The rigid cables are formed of a metal having an ultimate tensile strength of at least 500 MPa. The elastic cables are formed of a metal having a percentage elongation (engineering strain at fracture) of at least 30%, preferably between 40% and 80%. The rigid cables and elastic cables may be separate and spaced apart from one another, or intertwined with each other. The panels may be used to form an acoustic barrier.

Abstract: An air inlet grille for an appliance onboard an aircraft includes a screen having an inside-facing surface and an outside-facing surface, a plurality of airflow openings formed within the screen between the inside-facing surface and the outside-facing surface, and a plurality of tubes disposed on the inside-facing surface of the screen where openings on one end of the plurality of tubes are aligned with the plurality of airflow openings. A length of the plurality of tubes is at least twice a diameter of the plurality of airflow openings with which the plurality of tubes is aligned.

Abstract: A wedge-shaped, number theoretical acoustic diffuser both diffuses and reflects sound while eliminating wasted space created by prior art. The inventive diffuser consists of wells of continuously variable depths which provide wide-bandwidth diffusion in a single dimension. The back of the wells are reflective planes of a plurality of angles that direct energy away from the sound source. The invention may be installed in the upper corners of a room, with the deepest end of the wedge-shape up and tapering down to the thinnest end of the wedge shape. This installation allows floor standing furniture or other objects to be placed against the wall, an impossibility with the installation of prior art. The present invention may be installed as an array in which the deepest ends of the wedge shape are butted together. This formation splits and reflects sound in two different directions both away from the sound source.

Abstract: A liner assembly for an aircraft engine housing includes a noise attenuation structure that is covered by a face sheet. The face sheet covering the noise attenuation structure includes a surface having a plurality of circumferentially spaced apart acoustic energy absorption areas that are interspersed between a corresponding plurality of acoustic energy reflective areas. The acoustic energy reflective areas scatter higher order acoustic modes into a plurality of lower order modes. The difficult to attenuate lower order acoustic modes produced by the various acoustic energy cancel each other out to provide significant improvement in liner noise reduction efficiency.

Abstract: A construction machine capable of effectively reducing noise which would intrude into a cab, without deterioration in ride quality, comfort and air-conditioning efficiency in the cab is provided. The construction machine includes a lower propelling body, an upper slewing body including an upper frame, a cab including a floor plate and installed on the upper frame, and a cab noise reduction device. The cab noise reduction device includes: the floor plate; an under-cab member including a cab deck supporting the cab and provided under the cab to define a closed-form under-cab space whose periphery is substantially closed, in cooperation with the floor plate; and a resonator reducing noise in the under-cab space by a resonance effect.

Abstract: Honeycomb sections are bonded together with seams made up of an adhesive that is carried by a honeycomb seam support or 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 dampening structures.

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: A noise-emitting industrial plant is provided, which is enclosed by a personnel-accessible noise attenuation hood for damping noise which issues from the plant. The noise attenuation hood includes a horizontal working platform which is provided for maintenance operations and/or repair work. The working platform is arranged at the noise attenuation hood in a foldout manner.

Abstract: A sound-absorbing noise barrier, more specifically to one comprising: a main body which has a front surface and a rear surface and extends horizontally and in which a space is formed between the front surface and the rear surface; and a sound-absorbing material which is accommodated in the space of the main body and is disposed at a distance away from the front surface and the rear surface respectively, wherein the front surface of the main body is formed with vertically oriented alternating projections and recesses and is formed with a plurality of sound-absorbing holes, and the overall cross-sectional area of the sound-absorbing holes is at least 20% of the cross-sectional area of the front surface. The sound-absorbing noise barrier of the present invention can be variously employed in construction and industrial products, has good sound-absorbing characteristics across a wide frequency range, and can present an aesthetically appealing external effect.

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: Sound absorbing walls include a planar front panel element formed of an acoustically transmissive material and having a peripheral edge, a planar inner panel element formed of an acoustically absorbent material, having a peripheral edge, a front face abutting the front panel, and an opposed rear face, and a rigid frame having a panel portion overlaying the rear face of the inner panel element, and having a peripheral edge, and an edge portion forming a rim depending from the peripheral edge of the frame, and enclosing the peripheral edges of the front panel and inner panel. The frame may encapsulate the front panel and inner panel, except for an exposed front panel front surface. The rim may extend forward of the front panel. A sound wall may be constructed by connecting edge portions of one or more panels to spaced apart first and second ground-mounted vertical support columns.

Abstract: Compact, high-pressure exhaust muffling devices are disclosed. Some example muffling devices may include an inner flow conditioner including an inlet configured to convey a pressurized fluid flow into an inner flow conditioner interior. The inner flow conditioner may include a plurality of inner flow conditioner holes. The muffling device may include an exhaust can disposed substantially around the inner flow conditioner and arranged to receive the pressurized fluid flow via the inner flow conditioner holes into an exhaust can interior. The exhaust can may include a plurality of exhaust screen holes arranged to discharge the pressurized fluid flow from the exhaust can interior. The exhaust can interior may be substantially devoid of flow obstructions between the plurality of inner flow conditioner holes and the exhaust screen holes.

Abstract: A noise abatement wall includes a frame defining a window, at least one shell, at least one sheet of sound-insulating material and a sheet of screen material. The at least one shell has a base panel portion and a peripheral panel portion integrally formed with and extending perpendicularly from the base panel portion to surround the base panel portion thereby forming a shell cavity. The at least one shell is sized and configured to be received by the window in a close-fitting relationship therewith and is connected to the frame. The at least one sheet of sound-insulating material is disposed in and occupies the shell cavity. The sheet of screen material covers the at least one sheet of sound-insulating material and is connected to the frame. A plurality of noise abatement walls are connected together to form a noise abatement wall system for abating noise generated from stationary noise-generating equipment.

Abstract: The invention pertains to an insulation structure for thermally and acoustically insulating an aircraft that features at least one heavy layer, wherein the insulation structure according to the invention is characterized in that the insulation structure comprises an additional absorption layer, in that the heavy layer is perforated at least in certain areas, and in that the perforated area ratio of the heavy layer is adapted in such a way that the heavy layer is essentially transparent to sound for frequencies below a double-wall frequency of the insulation structure. This makes it possible to dampen sound with low frequencies below the double-wall frequency as effectively as possible.

Abstract: A monolithically fabricated sound absorbing structural precast concrete noise barrier panel comprising a sound absorbing layer of specialized raw materials. The raw materials include wood particles as well as granulated rubber.

Abstract: A system for venting a high-pressure flow stream is disclosed, the system comprising a device having a plurality of orifice plates, each orifice plate having a plurality of orifices, wherein the plurality of orifice plates are oriented relative to each other such that the pressure of the flow stream substantially drops.

Abstract: A monolithically fabricated sound absorbing structural precast concrete noise barrier panel comprising a sound absorbing layer of specialized raw materials. The raw materials include wood particles as well as granulated rubber.

Abstract: A method of forming a monolithically fabricated sound absorbing structural precast concrete noise barrier panel comprising a sound absorbing layer of specialized raw materials. The method includes providing a sound absorbing layer that is a blended mixture of an aggregate, granulated rubber, chemically treated wood particles, cement, pozzolans, water, air entraining admixture, and water reducing mixture; placing the sound absorptive layer ingredients in a form mold; compressing the ingredients to a preset density; backing the compressed ingredients with reinforced structural concrete; and curing the backed and compressed ingredients.

Abstract: A sound insulating trim part is provided. The sound insulating trim part includes an absorbing area and an insulating area. The absorbing area includes at least a first portion of a porous fibrous layer. The insulating area includes a mass layer and a decoupling layer. The mass layer includes a second portion of the same porous fibrous layer. The second portion has a dynamic Young's modulus (Pa) of at least about (96·AW·t) with AW being an area weight (g/m2), and t being a thickness (mm) of the porous fibrous layer. The mass layer also includes at least a substantially air impervious barrier layer between the porous fibrous layer and the decoupling layer. The thickness of the first portion of the porous fibrous layer in the absorbing area is larger than the thickness of the second portion of the same porous fibrous layer in the insulating area.

Abstract: A sound insulating trim part with acoustic mass-spring characteristics is provided. The sound insulating trim part includes a mass layer and a decoupling layer. The mass layer includes a porous fibrous layer with a dynamic Young's modulus E of at least about 96·AW·t (Pa), with AW being an area weight (g/m2), and t being a thickness (mm) of the porous fibrous layer. The mass layer also includes an air impervious thin barrier layer. The barrier layer is disposed between the porous fibrous layer and the decoupling layer. The barrier layer, the porous fibrous layer, and the decoupling layers are laminated together.

Abstract: A method for splicing honeycomb core together to form a core structure, such as an acoustic panel for an aircraft. The core structure may comprise a first honeycomb core, a second honeycomb core, and an intermediate bonding part disposed between the first and second honeycomb cores. The intermediate bonding part may comprise a syntactic core wrapped with or sandwiched between a non-foaming film adhesive. The syntactic core sandwiched between a first and second layer of film adhesive and a first and second honeycomb core is then compressed by vacuum and cured to bond the honeycomb cores together, forming the core structure.

Abstract: A monolithically fabricated sound absorbing structural precast concrete noise barrier panel comprising a sound absorbing layer of specialized raw materials. The raw materials include wood particles as well as granulated rubber.

Abstract: A jet engine noise suppression system uses a plurality of microjets that are located on a frame downstream of the exhaust port of a jet engine. Each microjet issues a microjet flow, either liquid or gas, directed at the main jet flow issued by the engine. The mass of the combined microjet flow is substantially smaller than the mass of the jet engine flow. The angle of at which each microjet issues its flow may be variable. The microjets may be located on a pop-up head of a blast deflector or on a upstanding rack.

Abstract: A jet noise source modeling method of creating a jet noise source model, includes: setting a plurality of point sound sources by quantizing a strength distribution of a jet noise source determined through an analysis of a jet stream and determining respective sound source strengths of respective point sound sources; and determining respective phases of the respective point sound sources based on a known noise level of a far free sound field related with the jet stream. An aircraft having an airframe capable of insulating the interior thereof from noises is designed on the basis of the results of the analysis.

Abstract: A noise-emitting industrial plant is provided, which is enclosed by a personnel-accessible noise attenuation hood for damping noise which issues from the plant. The noise attenuation hood includes a horizontal working platform which is provided for maintenance operations and/or repair work. The working platform is arranged at the noise attenuation hood in a foldout manner.

Abstract: A device for improving the effectiveness of the acoustic treatment(s) in an aircraft propulsion unit that includes a pipe (36) into which a gas stream flows, whereby the pipe (36) is delimited by two approximately concentric inside walls (40) and outside walls (42), wherein the device includes at least one partition (38, 38?) that extends over at least one portion of the length of the pipe (36) between the inside and outside walls (40, 42) and in that the profile of at least one wall (44, 46) of the at least one partition (38, 38?) is defined so as to increase the number of reflections of an acoustic beam on at least one of the inside and/or outside walls (40, 42) of the pipe and/or on at least one of the walls (44, 46) of the at least one partition (38, 38?).

Abstract: An exemplary fan assembly includes a fan and a muffler. The fan includes an air outlet. The muffler is disposed at the air outlet of the fan. The muffler includes a base plate. The base plate defines vents therein and blades thereon corresponding to the air outlet of the fan. The blades extend from the base plate toward the fan. An electronic device incorporating the fan assembly is also provided.

Abstract: Mobile soundproof enclosure with changeable internal room shape and optional ventillation noise cancelling device consisting of a frame that can be assembled and disassembled by a single person without using tools and that in disassembled state is small enough to fit in a trunk of a car; a cover made with flexible sound absorbent sheet material creating completely enclosed room with double walls with air space in between, corner sound traps made with flexible sound absorptive sheet material that can be individually positioned to change internal shape of the room and an air vent noise cancelling device made with flexible sound absorbing sheet material having inlet portion, which enters a center portion at an angle, the center portion larger than the inlet portion and outlet portion which exits the center portion at an angle; the whole enclosure can be disassembled to compactly fold for easy storage or transportation.

Abstract: A method and apparatus for the reduction of sound travelling in a wave-guide in the air above the ground is presented, comprising the provision below the ground of at least a top layer which, at the interface of the top layer and air, has an acoustic impedance which substantially matches the acoustic impedance of the air. Also a cylindrical structure with holes can be used. The method and apparatus may be used for the reduction of aircraft sounds, especially in the range of 15 Hz to 40 Hz, during the first part of take-off, wherein said layer(s) below the ground are provided in a range starting at a lateral side of the runway and extending until at least 100 meters, preferably until at least 300 meters and more preferably until at least 500 meters, from the runway.

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 viscoelastic medium having a speed of propagation of longitudinal sound wave and a speed of propagation of transverse sound wave, the speed of propagation of longitudinal sound wave being at least about 30 times the speed of propagation of transverse sound wave, and wherein the other of the first and second media is a viscoelastic or elastic medium.

Abstract: A noise suppression characteristics adjustment method includes adjusting noise suppression characteristics of a noise suppressor, which includes a muffler having a reflection plate for reflecting sound from the cooling fan, the reflection plate being provided at a position in the cooling duct confronting an intake plane of the cooling fan and formed substantially parallel to the intake plane. A sound-absorbing part of the muffler is provided on the reflection plate. A distance d between the reflection plate and the intake plane is set such that d<c/(2×f) where f is a sound-absorption frequency of the muffler and c is a speed of sound. The muffler is located inside the cooling duct. A through-hole is provided in the reflection plate. The through hole includes a plurality of through-holes. A resonance frequency of the resonator sound absorber is adjusted by blocking at least one of the plurality of through-holes.

Abstract: The present invention relates to a photovoltaic soundproof wall having a plurality of soundproof members each formed by surrounding the edge portions of two transparent sheets with a main frame and a plurality of posts adapted to mount the plurality of soundproof members therebetween, the photovoltaic soundproof wall including: a subframe disposed inside the main frame; a motor disposed inside the subframe for rotating a drive shaft rotatably mounted inside the subframe; a power transmission unit adapted to transmit the rotary force of the motor; a plurality of slats spaced apart from each other vertically between the two transparent sheets in such a manner as to be moved collectively by the power transmitted from the power transmission unit; and a plurality of solar cells attached to the top surface of each of the plurality of slats.

Abstract: A microphone for use in windy environments. The microphone uses a transducer to flood the environment outside the microphone with a high frequency (such as an ultrasonic) acoustic field. The sounds desired to be detected are mixed with the high frequency carrier, and can then be received by the microphone with less wind noise. The microphone then demodulates the desired sound signals from the high frequency carrier. The microphone can be configured in a special emitter-receiver configuration that also reduces interference from engine noise.

Abstract: An insulating isolator for a heat shield has a unitary first land, a bead portion, a second land and a half bead. The first land defines a fastener aperture. In one case, a plurality of circumferentially spaced apart petals is formed in the isolator. The petals may be separated by gaps. In another case, a set of circumferentially spaced apart apertures are formed in the isolator. The heat shield may have at least two disk apertures. Two metallic disks are located in the area of at least one of the two disk apertures. The metallic disks are connected to each other, have aligned fastener openings that are smaller than the disk apertures and they are smaller than the metallic sheet. One of the metallic disks may have a bead.

Abstract: The present invention relates to a soundproof cover containing: a sound-absorbing material disposed facing to a sound source; a soft sound-insulating layer laminated on the sound-absorbing material and having an air permeability measured according to JIS L 1018 (1999) of 10 cc/cm2·sec or less; and a soft cover forming an air layer with the soft sound-insulating layer and having a Young's modulus measured according to JIS K 7127 (1999) of 0.2 to 1.5 GPa, in which the air layer is hermetically sealed.

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 exhaust system for an electric power generation system is disclosed. The exhaust system may include a muffler configured to suppress noise associated with operation of an engine associated with the electric power generation system. The muffler may be configured to be mounted in a roof of a housing configured to contain at least part of the electric power generation system. The muffler may be configured to form an outside surface of the roof. Removal of the engine from the housing may be facilitated by removal of the muffler from the roof, such that the engine can be lifted out of the housing.

Abstract: A method and system for an acoustic panel system are provided. The system includes a plurality of acoustic panel segments aligned circumferentially about an inner diameter of a fan containment case wherein each segment includes a radially inner surface defining a portion of a fluid duct, a radially outer surface defining a gap between the fan containment case and the acoustic panel segment, and an aft end lip configured to be inserted into a mating groove in the fan containment case. The system also includes at least one damping bumper coupled to the radially outer surface wherein the bumper extends from the radially outer surface to the fan containment case and comprises an energy absorbing elastomeric material configured to facilitate dissipating a forced response of a vibratory stimulus.

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 present invention provides a soundproof cover comprising: a sound-absorbing material having air permeability; and a skin material impregnated with a viscoelastic material and having air permeability, wherein the skin material is provided on a surface of the sound-absorbing material opposite to a sound source, and wherein the soundproof cover has a three-dimensional shape corresponding to an outer shape of the sound source.

Abstract: Disclosed is a noise insulation device for aircraft, comprising a first opening that is delimited by a series of conducting surfaces whose inner edge is oriented towards the interior of the noise insulation device from a horizontal cross-sectional perspective and whose outer surface is directed towards the side, a roof, and a second opening which is located opposite the first opening and is delimited by walls. The inventive noise insulation device is characterized in that the size of the second opening can be modified by making changes to the walls.

Abstract: An acrylic glass plate for use as an opaque noise protection element in noise protection walls, the plate measuring a minimum of 2×2 m and having a minimum thickness of 8 mm wherein threads, strips, grids or networks consisting of a material which is incompatible with the acrylic glass are integrated into the acrylic glass for binding splinters in the event of a fracture of the plate, and the plate comprises between 40 and 80 wt. % of filling materials, in relation to its total weight (calculated without integrated threads, strips, grids or networks); and a method for producing such plates.

Abstract: A computer system includes a chassis with a fan installed therein, a cover plate adapted to be attached to the chassis, and a noise absorber attached to the cover plate. The fan is capable of generating an amount of air flow for cooling at least a component in the chassis. The noise absorber includes a plurality of protrusions facing the fan and capable of damping the air flow that impacts the cover plate and decreasing an acoustic noise level of the computer system.

Abstract: An aero-acoustic aviation engine inlet with a single air blowing slot or multiple air blowing slots flows air over one or more segments of inlet acoustic lining surfaces at speeds that are higher than the inlet mean air flow speed, for aggressive inlet noise abatement.