Abstract: Provided is a soundproof structure body including an opening member that forms an opening tube line having a cross-sectional area S, and at least two resonance structures for sound waves that are installed inside the opening tube line, and in a case where a cross-sectional area of the resonance structure is defined as Si, a width thereof is defined as di, an interval between the two resonance structures is defined as L, an impedance of the two resonance structures is defined as Zi, and a synthetic acoustic impedance is defined as Zc, a condition of Expression (1) is satisfied at a resonance frequency f0 at which a theoretical absorption value At is a maximum value. This soundproof structure body can realize high absorption using a plurality of resonance structures. At(f0, L, S, Si, di, Zi)>0.

Abstract: An acoustic attenuation panel for a propulsion assembly includes an acoustic front skin having perforations, and a central structure formed from partitions arranged perpendicularly in order to make up cells, wherein the front skin and the central structure form the panel which is made as a single piece and is provided for directly covering a surface of an element of the propulsion assembly forming a rear skin which closes the cells of the central structure at the rear.

Abstract: An electric motor with a stator that is formed of a plurality of distinct laminations. Each of the distinct laminations has a radially inner lamination edge, which borders a rotor aperture configured to receive a rotor therein, a radially outer lamination edge and a plurality of cooling apertures formed there through that are disposed radially between the radially inner and outer lamination edges. Each cooling aperture in a lamination forms part of a separate and distinct cooling channel that extends helically through the laminations about a rotational axis of the electric motor.

Abstract: A device for damping hydrosound in liquid having a frequency range emitted from a sound-emitting body in the liquid includes: a plurality of individual gas volumes distributed in the liquid in an area of the sound-emitting body and at a distance from each other, each of the individual gas volumes being operable to reduce the hydrosound through resonant oscillations; and at least one mass body disposed in the liquid, the individual gas volumes being connected to the at least one mass body so as to prevent the individual gas volumes from rising up in the liquid.

Abstract: The present disclosure relates to an acoustic absorption system. The acoustic absorption system can include a curtain that includes one or more acoustic absorption panels. The curtain can be cleanable and/or sanitizable, and can be flame resistant. The curtain can also be coupled to an extension member.

Abstract: The present invention relates to the field of 4D printing, and particularly to an electro-responsive folding and unfolding composite material for 4D printing, a method for manufacturing the same, and a method for regulating shape memory behavior thereof. In the process of layer-by-layer printing, conductive layers are embedded into a pre-designed shape memory polymer matrix through spray-coating and laser-irradiation nano-fusion welding, to manufacture a folding and unfolding structure with electro-responsive shape memory behavior. The distribution and range of heat affected zones in the electro-responsive shape memory folding and unfolding structure are controlled by adjusting the number of electric heating layers energized and the value of an energizing voltage. The speed of shape recovery and the degree of shape recovery of the structure are regulated according to a magnitude relationship between a shape recovery force Frecovery and a resistance Fresistance to shape recovery of the structure.

Abstract: A sound attenuating baffle device has a baffle casing supported within a duct such that a boundary wall of the baffle device is oriented in the flow direction from the leading end to the trailing end of the baffle casing. The baffle casing includes a sound attenuating structure therein, and a trailing member protruding outwardly beyond the trailing end of the baffle casing towards a free trailing edge of the trailing member which is non-linear in profile. As compared to a continuous, straight trailing edge as found on most silencer outlets, a non-linear profile, for example a V-shaped or saw-toothed edge, improves the flow distribution along the height of the baffle or perimeter of the centerbody. The distribution of airflow across the resulting extended tail edge represents an improvement in the flow recovery.

Abstract: Provided herein is a system and method for cooling of a vehicle. The system comprises an enclosure disposed on the vehicle. The enclosure comprises a fan disposed at a base of the enclosure, one or more sensors within the enclosure, and a cover on an exterior of the enclosure. The cover comprises a hole pattern to selectively permit an airflow to enter the enclosure. The hole pattern comprises a plurality of holes to filter noise from the airflow. A deflector is disposed on the vehicle outside the enclosure and configured to direct an airflow through the hole pattern.

Abstract: A novel design for desiccant air dryer pneumatic mufflers includes a core comprising a perforated inner tube with baffles attached to the outside surface of the inner tube. The inner tube is positioned in the interior of an outer tube, and a cap is positioned on one end of both tubes. The interior portion of the cap is solid so that it blocks the flow of air at the end of the inner tube, forcing the air to flow through the perforations in the inner tube and into the outer tube. The perimeter of the cap is perforated so that the air exits the muffler.

Abstract: An acoustic absorption structure comprising a plurality of resonators. Each resonator comprises a first chamber which has a first mouthpiece delimited by an edge pressed against an inner surface of a porous zone of a skin so that the first chamber and the skin delimit a first cavity, a second chamber, in which is positioned the first chamber, which delimits, with the first chamber, a second cavity, at least one acoustic orifice passing through the first chamber, at least one drainage orifice passing through the first chamber and at least one drainage hole passing the second chamber, each drainage orifice and each drainage hole being configured to limit an accumulation of fluid in the resonator. Also, an aircraft propulsive assembly or an aircraft comprising the acoustic absorption structure are provided.

Abstract: An acoustic panel is provided that includes a perforated first skin, a second skin and a core. The core includes a first wall, a second wall and a stiffener. The core forms a plurality of cavities that extend vertically between the perforated first skin and the second skin and that extend laterally between the first wall and the second wall. The plurality of cavities include a first cavity. The stiffener projects partially into the first cavity and is connect to the first wall and the second wall.

Abstract: Disclosed herein are implementations of acoustic metamaterial structures and geometric configurations of acoustic metamaterial structures which produce sound amplification or cancellation. An acoustic metamaterial device for using with a sound source includes a plurality of fins, where each fin is made from a very dense material with respect to air which creates the anisotropic properties of the acoustic metamaterial device, where each fin has a length dimension, a width dimension, and a thickness dimension, the width and length dimension being equal and substantially perpendicular to the direction of sound wave propagation from the sound source, where each fin is sized different from other fins along the width and length dimension, and where the plurality of fins are interconnected such that planes formed by the width and length dimension of each fin faces perpendicular to the sound wave propagation direction from the sound source.

Abstract: A method of designing an acoustic liner includes identifying acoustic path lengths that will attenuate a frequency within a frequency range of interest, and selecting a liner configuration with a combination of acoustic paths that addresses the frequency range of interest. The selection may be made after a comparison of the response of different liner configurations.

Abstract: The present invention is directed to an improved gypsum board, such as an improved sound damping gypsum board. The gypsum board comprises a gypsum core including gypsum and a sound damping polymer. The gypsum core includes a first gypsum layer surface and a second gypsum layer surface opposing the first gypsum layer surface. In addition, a first encasing layer is disposed on the first gypsum layer surface and a second encasing layer is disposed on the second gypsum layer surface.

Abstract: A Helmholtz resonator having a plurality of resonator chamber modules formed into an array. The array is configured to dampen sound. A module of the plurality of resonator chamber modules includes a first chamber and a second chamber. The first and second chambers have different lengths and are tuned to dampen different frequencies of sound.

Abstract: A sound isolation device includes at least one degenerate acoustic scatterer having a plurality of channels. The plurality of channels may include three or more channels. The channels have an open end and a terminal end, wherein the terminal ends of the channels are separate from one another. The at least one degenerate acoustic scatterer has an acoustic monopole response and an acoustic dipole response that have a substantially similar resonant frequency.

Abstract: A vehicle wheel includes: a rim including a well portion with an outer circumferential surface, the well portion having a recessed portion formed on the outer circumferential surface; a sub-air chamber member serving as a Helmholtz resonator; and a joining member including a joining portion disposed in the recessed portion. The sub-air chamber member is attached to the outer circumferential surface of the well portion via the joining member.

Abstract: An assembly includes a panel member and an acoustic sink member. The panel member has a panel edge, and first and second long axes defining a plane. The panel member has a first material composition. The acoustic sink member has a body with a periphery which is coupled to the panel edge. The body has a second material composition, which is distinct from the first material composition. An acoustic impedance of the sink member at the periphery is equal to an acoustic impedance of the panel member at the panel edge, and the body has a cross-sectional profile defined by a power law.

Abstract: Provided is a vehicle wheel with which manufacturing costs can be reduced. The vehicle wheel includes a sub air chamber member as a Helmholtz resonator on a well portion of a rim. The sub air chamber member includes a protrusion portion which protrudes toward the rim, and the rim has a hole portion into which the protrusion portion is inserted to engage with the sub air chamber.

Abstract: An enclosure for a genset comprises a container defining an internal volume for housing the genset. The container comprises a container floor, a container roof, a pair of container sidewalls disposed parallel to a longitudinal axis of the container, and a pair of container endwalls disposed at longitudinal ends of the container. A side cap is positioned parallel to each of the pair of container sidewalls along a longitudinal length of the container, each of the side caps sealed to edges of the corresponding container sidewall so as to define an acoustic cavity therebetween.