Abstract: A structure for absorbing wave energy, particularly acoustic wave energy, which includes a first essentially planar surface against which wave energy is directed and a second essentially planar surface generally parallel to and spaced from the first surface. Wedge-shaped elements of sound-absorbing material are disposed between the planar surfaces. All of the wedge-shaped elements, which may be of triangular cross section or pyramidal, have generally flat base portions which form said first planar surface against which wave energy is directed. The apex portions of the wedge-shaped elements are in substantial abutment with the second planar surface. The invention has utility in anechoic applications; however, in contrast to prior art structures of this type, the apex portions of the sound-absorbing material face away from incident wave energy rather than facing toward it.

Abstract: A structure for decreasing low frequency air vibrations, comprising a sound insulating floor, sound insulating sidewalls and a sound absorbing ceiling arranged so as to form an air chamber below and separate from the underside of an elevated road or railway bridge's traversed surface, thereby forming a space between the sound absorbing ceiling and the elevated bridge. The structure is very effective for decreasing the low frequency air vibration emanating from the structure of the elevated bridge and the low frequency air vibrations transmitted from the structural supports of the elevated bridge.

Abstract: Multiple membranes which are transparent, translucent, opaque or otherwise limit electromagnetic radiation are employed in an easily manufactured and transported roll which can be unrolled, cut to length, expanded, erected and sealed, thereby creating a thermally and acoustically insulating electromagnetic wave-limiting panel with separate dead air space separated by said multiple tensioned membranes.

Abstract: A sound barrier system particularly suited for out-of-doors, ground-mounted installations, such as for a highway noise barrier, comprises a vertical wall composed of successive individual wall sections arranged with immediately adjacent wall sections disposed at an intersecting angle to each other. Immediately adjacent wall sections are rigidly joined together in abutment along a common vertical joint. An earth anchor is anchored into the ground at each vertical joint. Each joint is secured to the corresponding earth anchor so that downwardly directed hold-down forces are applied by the earth anchors to the wall at the bottom portions of the joints.

Abstract: The invention relates to a sound damping material in the shape of foils or strips comprising open-pored foam material impregnated with different quantities of a viscoelastic compound, which is intended for application to attenuated structures, particularly automobile body panels.

Abstract: A noise barrier or other type wall or building assembly includes a plurality of spans each extending between spaced apart posts and having top and bottom girts affixed to the posts and in turn supporting a plurality or series of vertically disposed panels. Unique mating interlock elements integrally formed along both lateral edges of the wall or building exterior panels allow the sequential interconnection of all panels in a series by means of a rotating displacement of the individual panels to yield multilateral interlocking of the panels. The panel faces are configured to provide shadow texture, while masking of the posts and top girts in a free-standing type wall is obtained by a split cover assembly and split cap trim, respectively.

Abstract: An improved sound absorptive tackable space dividing wall panel or similar article in which a wire mesh screen is disposed within the sound absorptive material a distance from the tackable surface less than the length of the tack pin, thereby providing additional support for the tackable load without appreciably reducing the sound absorptive characteristics of the panel.

Abstract: A method for producing an acoustical ceiling tile or panel faced with a distortion free decorative thin plastic film is accomplished by first embossing the acoustical base to form a picture frame surrounding a recessed area, stretching the thin decorative plastic film over the picture frame portion and adhesively securing the film to the side and/or back of the acoustical base and subsequenytly heat shrinking the film to produce a distortion free decorative surface.

Abstract: A noise reducing liner panel, such as a headliner and interior panel, and the like for motor vehicles, formed of a lamination of a substantially rigid, plastic sheet, a thin, flexible, foam plastic layer, and an outer fabric covering, all bonded together while flat. Numerous, small, closely spaced perforations are formed in pre-determined areas in the rigid sheet before laminating. The initially flat, rigid sheet is permanently bent and distorted, after the bonding, into pre-determined cross-sectional contours and shapes, including forming relatively deep depressions in the uncovered surface of the rigid sheet, at pre-selected areas, which depressions include areas of perforations. The depressions may be filled with sound absorbing materials, such as pieces of foam plastic, for thereby forming selected panel areas with greater sound absorbing capacity.

Abstract: A noise barrier pad and a method for the production of same comprises the steps of forming a tread layer by reacting a mixture for polyurethane foam in a hollow mold having separable upper and lower parts and which is shaped so as to form the tread layer, curing the foam, removing the upper part of the mold, placing a blank of noise barrier material on the surface of the foam which corresponds to the bottom side of the tread layer, and forming a bottom foam layer on the tread layer and barrier material by placing another upper mold constructed in accordance with the bottom layer of the noise barrier pad and defining a cavity over the tread layer and barrier material and filling the cavity with the reaction mixture for the polyurethane foam.

Abstract: A fibrous shaped article having a surface with raised and depressed portions, said fibrous article consisting of a unitary laminated structure resulting from the compression molding under heat of (A) a heat compression-moldable nonwoven fibrous web and (B) a nonwoven fibrous sheet, said fibrous sheet (B) being laminated to at least one surface of said fibrous web (A); said fibrous web (A) having a compression stress, at 10% compression at the temperature of said compression molding, of at least 0.5 g/cm.sup.

Abstract: A laminated noise attenuation panel for both sound absorption and sound transmission loss having as its principal layers an expanded thermoplastic core with alternately inverted cavities, half opening to each side of said core and a sheet of cured resinous material having hollow microspheres with substantially reduced atmospheric pressure randomly dispersed in said resinous material, said cured resinous sheet facing away from the noise source. The cavities of said core panel facing away from said noise source may be filled with cellulose. The side of said core panel toward the noise source may include a laminated layer of a perforated material and a decorative layer. The side of said panel away from the noise source may also include a layer of other materials and a decorative layer. Data for the noise attenuation properties of various combinations of laminations are presented.

Abstract: A noise barrier wall having a transition area in the region of at least one unbounded edge and which employs controlled diffraction of sound to enhance the sound reducing properties thereacross. The transition area of the noise barrier is provided with either a row of absorptive shaped splitter panels, or a row of pickets, or other means of controlled transparency which provide acoustical shadowing equal to or greater than that of a solid wall for the frequency regions of interest.

Abstract: An acoustical panel for reducing acoustic noise is disclosed. The panel is comprised of a corrugated sheet of material. The sheet of material has a generally parabolic-sinusoidal configuration forming a plurality of corrugations. The corrugations extend in a first direction and form a plurality of peaks and valleys. At least one side of the panel has a surface adapted to face a source of acoustical noise. The surface acoustically diffuses acoustic waves striking the surface and causes acoustic wave interference to occur. The acoustic panel has a transaxial stiffness-compliance such that the panel is permitted to pump when low frequency acoustic energy is applied to the panel for the purpose of dissipating acoustic energy.

Abstract: An acoustical insulating material comprises a fiber reinforced lead composite sheet or panel. In a preferred embodiment of the invention the fibers are substantially axially parallel aligned with one another. The frequency absorption and transmission characteristics of the material may be varied by mechanically stressing the material, e.g. as by placing the material under tension in the direction of fiber orientation.

Abstract: The sound absorbing and diffusing unit is provided for assembling an acoustic screen which can be placed or hung in front of a wall inside an acoustic room for improving a sound-effect therein. These units are detachably joined together with each other so that they may be easily separated and assembled again to form an acoustic screen having another shape or construction to adjust or modulate a sound-effect. A sound absorbing porous panel having a desired picture or pattern can be easily hung against a wall. The decorative panel can be reversely hung on the wall to provide another interior ornamentation. Accordingly, an acoustically correct room and a desired ornamentation on a wall inside the acoustic room can be easily obtained and changed without providing a rigid reverberating surface of the room.

Abstract: Prefabricated element arranged on a single wall of a room for forming a double sound insulating and sound absorbing wall. The prefabricated element provides efficient sound insulation of the room and a total sound absorption of sound waves whose frequency is centered at one of the natural frequencies of the room. The element comprises a frame supporting a flexible panel by means of elastic sealing means, the flexible panel being maintained at a predetermined distance from the single wall due to the thickness of said frame whereby the resonant frequency of the double wall becomes equal to a natural resonant frequency of the room corresponding to sound waves propagating perpendicularly to the single wall. In addition, the prefabricated element may also comprise an additional element placed in the middle of the panel which permits equalization of the natural resonant frequency of the assembly comprising the flexible panel and the additional element to the low natural frequency of the room.

Abstract: A noise barrier wall having a transition area in the region of at least one unbounded edge and which employs controlled diffraction of sound to enhance the sound reducing properties thereacross. The transition area of the noise barrier is provided with either a row of absorptive shaped splitter panels, or a row of pickets, or other means of controlled transparency which provide acoustical shadowing equal to or greater than that of a solid wall for the frequency regions of interest.

Abstract: An underwater acoustic absorber and reflector having an impervious rigid al bonded to a rubber tile. When installed on baffle plates of an underwater vehicle the absorber maintains its efficiency under hydraulic pressure.

Abstract: A perlite sound absorbing plate and a sound insulating wall constructed by arranging a number of said plates side by side and by assembling together into one integral body are disclosed. The plate is composed of a mixture including 1,000 cm.sup.3 by bulk volume of formed perlite particles each having a diameter of 0.1 to 7.0 mm, 100 to 140 g of cement, liquid rubber latex containing 5 to 20 g of solid ingredients and a suitable amount of water and produced by press molding with a compression ratio of 1.10 to 1.30. The wall is constructed by assembling a number of said plates each provided with a side groove with the aid of supporting columns and reinforcing plates, each having a ridge adapted to be engaged with the side groove of said plate.

Abstract: The disclosed foam laminate preferably includes a corrugated paper sheet, a layer of thermosetting resin foam wherein the corrugations extend into and are bonded to the foam layer and a relatively flexible finish sheet bonded to the foam layer. The corrugated sheet preferably includes a corrugated paper sheet bonded to a relatively flat sheet. In the disclosed automotive headliner, the corrugations preferably extend perpendicular to the headliner side edges, providing support for the concave midportion of the headliner and preventing delamination of the paper and foam laminae.

Abstract: The noise protection screen of the present invention comprises a plurality of hollow tubular members, preferably of equal length and substantially elliptical in cross-section. The hollow members are formed of a flexible material and inclined at an angle to the horizontal. The hollow members are interconnected by corresponding tongue-and-groove engagement whereby the engaged grooves are deformed in a manner to provide a clamping action of the grooves about the corresponding tongues.

Abstract: The sound absorbing and diffusing unit is provided for assembling an acoustic screen which can be placed in front of a wall inside an acoustic room for improving a sound effect therein. These units are detachably joined together with each other so that they can be easily separated and assembled again to form an acoustic screen or partition having another shape or construction to adjust or modulate a sound effect. A decorative sound absorbing porous panel having a desired picture or pattern can be easily hung against a wall. The decorative panel can be reversely hung on the wall to provide another interior ornamention. Accordingly, an acoustically correct room and a desired ornamentation on a wall inside the acoustic room can be easily obtained and changed without providing a rigid reverberating surface of the room.

Abstract: A noise control enclosure comprises an assembly of a plurality of panels each having a structural framework on which a sound deadening sheet material is affixed. The structural framework is formed of frame members which have mounting flanges which are disposed about the periphery of the structural framework of each panel. The sound deadening sheet is permanently affixed thereto, for example by a suitable adhesive. Individual panels are removably connected to each other to form the enclosure by fastening means such as self-tapping screws. The sheet material is interposed between abutting frame members of adjacent panels. Peripheral edges of the sheets mounted on the framework or strips of similar material extend between abutting frame members of the structural framework to provide acoustic sealing between panels. The individual panel construction permits on site assembly and disassembly.

Abstract: An improved thermally and acoustically insulating structure provides both a high average acoustical transmission loss for incoming sounds of particularly low frequency range and a thermally insulating and anti-dewing effects. The structure includes at least three glass sheets defining air spaces of different width therebetween, the air enclosed in the spaces circulating therebetween through air passages to be kept dry and at least one air space having means to prevent the effect of Newton's rings of beams of light incident on the outer glass sheet.

Abstract: A sound absorbing body which can effectively be utilized as an exterior sound absorbing wall or an interior wall of a house is disclosed. The sound absorbing body comprises a number of sound absorbing cavities inclined at an angle .alpha. which is smaller than 80.degree. with respect to a transverse horizontal sectional plane of the body, the sound absorbing cavities being opened at the sound incident surface.

Abstract: High temperature resisting cordage is wrapped around an exhaust gas muffler housing and covered with an outer wrap of metal to provide sound and thermal insulation for the muffler.

Abstract: A composite panel is described in which the face sheets and the core have properties such that the panel produces a double wall resonance near the low frequency end of the principal speech bands and in which the panel produces interaction between the symmetric and antisymmetric mode in the principal speech bands, thereby providing greater than mass-law transmission loss over a substantial portion of the audio frequency spectrum. At frequencies above the principal speech bands effects are determined primarily by the properties of the individual face sheets.

Abstract: An anti-abrasive, flame-resistant, and noise-suppressant laminate suitable for use with underground scraper conveyors or the like comprising two outer layers of ferrous material having an inner layer of styrene butadiene rubber material vulcanized therebetween. The styrene butadiene rubber material has a durometer of the order of 59, a flame spread index of less than 25 according to ASTM-E162 and a thickness of the order of 1/4 inch. One of the outer layers is of abrasive resistant steel and has a thickness of the order of 1/4 inch. The other outer layer is of 1020 steel and has a thickness of 16 gage.

Abstract: A sound barrier and sound-absorption panel preferably of a transparent nature so as not to interfere with vision of and light for the machine or other noise-emitting device, to be shielded or enclosed by one or more of the panels. The panel is formed of transparent sound-reflecting material and sound-absorbing material so arranged relatively that the sound waves are received by the panel and deflected into the sound-absorbing material. The reflecting material and sound-absorbing material are arranged to provide one or more sound-receiving pockets or cavities each of which has an outwardly-diverging sound-reflecting wall surface which faces toward the sound-emitter. The sound-absorbing material is in the form of an outwardly-extending member so located in the pocket or cavity as to absorb sound waves which are received in the pocket or cavity and are deflected into the sound-absorbing member by the sound-reflecting wall surface.

Abstract: A plane plate of corrugated paperboard, which is produced by bonding a corrugated medium and at least one liner board with a thermoplastic resin, is shaped into a curved plate by means of a hot-press so that the resin fluidifies and allows the medium and each liner board to make individual and slipping movements during press-forming. The resin hardens upon subsequent temperature reduction and affords the curved heat and sound insulator plate a good shape retentivity.

Abstract: A honeycomb type core configuration for composite structural panels generated by folding sheet material. The box shaped core, when attached to a surface sheet imparts rigidity to the sheet for use as a high strength to weight ratio structural sheet panel. The cell walls of the folded core are integral with the cell bottom which provides a large surface area for ease of attachment to the surface sheet.

Abstract: A sound-attenuating inlet duct is provided for a gas turbine engine wherein the inlet duct includes a casing defining, in serial flow relationship, a minimum area throat of predetermined axial extent, a diffuser and a cylindrical section. Sound-absorbent acoustic material is disposed upon the inner walls of the duct in the cylindrical section. A first amount of acoustic attenuation is provided by accelerating the motive fluid to high subsonic velocities through the throat. A second amount of acoustic attenuation is provided by locally accelerating the motive fluid in the vicinity of the acoustic material, thereby imparting a velocity component to the acoustic waves which is normal to the acoustic material, thereby enhancing absorption. By sizing the various sections of the inlet duct in a unique predetermined relationship the effects of the two sources of acoustic attenuation may be made additive.