Abstract: Disclosed are systems and devices for absorbing flexural waves. In one example, a pair of scatterers for absorbing a flexural wave acting on a structure includes a monopole scatterer and a dipole scatterer configured to be mounted to the structure at the same location.

Abstract: An acoustic structure includes at least one acoustic scatterer that is angle independent and has multiple resonant frequencies. Each acoustic scatterer contains at least one repeated cell. Each cell contains at least two distinct resonant channels capable of absorbing sound and improving sound transmission loss at distinct frequencies. Each resonant channel is identical to at least one other channel within the acoustic scatterer.

Abstract: Disclosed are systems for absorbing and/or isolating vibrations and/or flexural waves acting upon a structure using scatterers. In one example, a system for absorbing a flexural wave acting upon a structure includes a pair of scatterers adhered to the structure using an adhesive having a property that is based on a reduction of the flexural wave at a peak frequency by the pair of scatterers.

Abstract: A system for isolating sound generated by an aircraft utilizing a helipad may include a plurality of acoustic scatterers being disposed adjacent to at least a portion of a perimeter of the helipad. Each of the plurality of acoustic scatterers include channels having an open end and a terminal end. Additionally, each of the plurality of acoustic scatterers has an acoustic monopole response and an acoustic dipole response with a resonant frequency that is substantially similar to one another.

Abstract: Disclosed are systems and devices for absorbing flexural waves using monopole and dipole resonance. In one example, a system includes a monopole scatterer coupled to a first side of a structure at a first location and a dipole scatterer coupled to a second side of the structure at a second location that at least partially overlaps the first location. At least one of the monopole scatterer and the dipole scatterer includes a lever.

Abstract: An acoustic structure includes an acoustic scatterer with a plurality of repeating cells and a corresponding plurality of resonant channels such that the acoustic scatterer is an angle independent acoustic absorber. The plurality of resonant channels each have an open end and a terminal end, and foam extends across the open ends of the plurality of resonant channels. And a layer of foam extending around the acoustic structure and/or or positioned at open ends of the resonant channels broadens the absorption and sound transmission loss bandwidth.

Abstract: Disclosed are systems for directing flexural waves acting upon a structure. In one example, a system includes a beam and a pair of scatterers disposed on the beam and configured to induce a flexural wave on the beam when actuated at a frequency. The system is configured to direct a direction of travel of the flexural wave acting on the beam based on the width of the beam, the distance between the scatterers forming the pair of scatterers, and/or a phase difference between the actuation of the pair of scatterers.

Abstract: An acoustic structure includes at least one acoustic scatterer that is angle independent and has multiple resonant frequencies. Each acoustic scatterer contains at least one repeated cell. Each cell contains at least two distinct resonant channels capable of absorbing sound and improving sound transmission loss at distinct frequencies. Each resonant channel is identical to at least one other channel within the acoustic scatterer.

Abstract: An acoustic structure includes at least one coupled pair of Helmholtz resonators that have an inner wall, a first rectangular shaped Helmholtz resonator with a first inner volume on one side of and partially defined by the inner wall, and a second rectangular shaped Helmholtz resonator with a second inner volume on another side of and partially defined by the inner wall.

Abstract: Disclosed are systems and devices for absorbing flexural waves. In one example, a pair of scatterers for absorbing a flexural wave acting on a structure includes a monopole scatterer and a dipole scatterer configured to be mounted to the structure at the same location.

Abstract: Disclosed are systems for absorbing and/or isolating vibrations and/or flexural waves acting upon a structure using scatterers. In one example, a scatterer includes a pair of supports separated from each other by a distance, a flexible material extending between the supports, and a mass disposed on the flexible material. The flexible material acts as a spring and damper in a mass-spring-damper system, while the mass acts as a mass in a mass-spring-damper system. This scatterer may also include the ability to be switched on/off by placing a member within a cavity defined between the supports and the flexible material.

Abstract: Disclosed are systems for absorbing and/or isolating vibrations and/or flexural waves acting upon a structure using scatterers. In one example, a system for absorbing a flexural wave acting upon a structure includes a pair of scatterers adhered to the structure using an adhesive having a property that is based on a reduction of the flexural wave at a peak frequency by the pair of scatterers.

Abstract: A metal-air battery includes an anode, a porous cathode, a separator between the anode and the porous cathode, a liquid electrolyte, and at least one acoustic device. The acoustic device produces acoustic waves at a frequency that pumps the liquid electrolyte through and into flowing contact with the porous cathode such that a discharge product is removed from the porous cathode. An accumulation compartment where the discharged product is collected after being removed from the porous cathode can also be included.

Abstract: Systems and devices are disclosed herein for absorbing unwanted target sounds. In one example, an acoustic scatterer for absorbing a target sound includes a housing defining a plurality of channels having an open end and a terminal end. The terminal ends of the plurality of channels are separate from each other and extend along a length of the housing. The acoustic scatterer also includes one or more spacers subdividing the plurality of channels along the length of the housing. In another example, a system for absorbing a target sound includes a plurality of acoustic scatterers, each having a housing that defines a plurality of channels having an open end and a terminal end. The terminal ends of the plurality of channels are separate from each other and extend along a length of the housing. The plurality of acoustic scatterers are stacked on top of each other in a lengthwise direction.

Abstract: A flexural wave absorption system may include a pair of resonators disposed on the structure and separated from each other by a separation distance. The pair of resonators are arranged on the structure in a direction substantially similar to the direction of the flexural wave acting on the structure. As to the separation distance, this distance may be approximately one-quarter of the wavelength of the flexural wave acting on the structure.

Abstract: A method for beaming sound waves includes introducing sound waves into a phononic crystal in a first direction. The phononic crystal has an array of C-shaped structures oriented so that a neck of each of the C-shaped structures is facing the same general direction. The sound waves are beamed in the direction in which the neck of each of the C-shaped structures is facing so that the sound waves are beamed from the phononic crystal in a second direction that is different from the first direction.

Abstract: Systems and devices are disclosed herein for absorbing unwanted target sounds. In one example, an acoustic scatterer for absorbing a target sound includes a housing defining a plurality of channels having an open end and a terminal end. The terminal ends of the plurality of channels are separate from each other and extend along a length of the housing. The acoustic scatterer also includes one or more spacers subdividing the plurality of channels along the length of the housing. In another example, a system for absorbing a target sound includes a plurality of acoustic scatterers, each having a housing that defines a plurality of channels having an open end and a terminal end. The terminal ends of the plurality of channels are separate from each other and extend along a length of the housing. The plurality of acoustic scatterers are stacked on top of each other in a lengthwise direction.

Abstract: A system for isolating sound generated by an aircraft utilizing a helipad may include a plurality of acoustic scatterers being disposed adjacent to at least a portion of a perimeter of the helipad. Each of the plurality of acoustic scatterers include channels having an open end and a terminal end. Additionally, each of the plurality of acoustic scatterers has an acoustic monopole response and an acoustic dipole response with a resonant frequency that is substantially similar to one another.

Abstract: A method for beaming sound waves includes introducing sound waves into a phononic crystal in a first direction. The phononic crystal has an array of C-shaped structures oriented so that a neck of each of the C-shaped structures is facing the same general direction. The sound waves are beamed in the direction in which the neck of each of the C-shaped structures is facing so that the sound waves are beamed from the phononic crystal in a second direction that is different from the first direction.

Abstract: A sound absorbing structure includes a panel having a first side and a second side and at least one acoustic scatterer coupled to a first side of the panel. The panel may be at least partially transparent. The at least one acoustic scatterer has an opening and at least one channel. The at least one channel has a channel open end and a channel terminal end with the channel open end being in fluid communication with the opening. The panel may be utilized to separate an interior space from an exterior space.