Disclosed a molded body including: a plurality of cavity portions formed inside a molding material; and a plurality of neck portions provided in each of the plurality of cavity portions and configured to communicate with the cavity portions, wherein some of the plurality of neck portions communicate with a surface and/or the cavity portion exposed on the surface, wherein at least some of the plurality of neck portions cause the plurality of cavity portions to communicate with each other, and wherein an inner surface of the neck portion is formed by the molding material itself.

Disclosed a molded body including: a plurality of cavity portions formed inside a molding material; and a plurality of neck portions provided in each of the plurality of cavity portions and configured to communicate with the cavity portions, wherein some of the plurality of neck portions communicate with a surface and/or the cavity portion exposed on the surface, wherein at least some of the plurality of neck portions cause the plurality of cavity portions to communicate with each other, and wherein an inner surface of the neck portion is formed by the molding material itself.

A system for fabricating an acoustic metamaterial is provided. In an embodiment, a system for fabricating an acoustic metamaterial includes determining at least one tuned physical property for each of a plurality of micro-resonators according to a desired acoustic property of the acoustic metamaterial. For a particular physical property, a value of the tuned physical property for at least one of the plurality of micro-resonators is different from a value of the tuned physical property for at least one other of the plurality of micro-resonators. The system also includes an additively manufacturing device configured to form the acoustic metamaterial such that the acoustic metamaterial comprises a first structure and the plurality of micro-resonators embedded within the first structure. Forming the acoustic metamaterial is performed such that an actual physical property of each of the plurality of micro-resonators is equal to a corresponding tuned physical property for each of the plurality of micro-resonators.

A system for fabricating an acoustic metamaterial is provided. In an embodiment, a system for fabricating an acoustic metamaterial includes determining at least one tuned physical property for each of a plurality of micro-resonators according to a desired acoustic property of the acoustic metamaterial. For a particular physical property, a value of the tuned physical property for at least one of the plurality of micro-resonators is different from a value of the tuned physical property for at least one other of the plurality of micro-resonators. The system also includes an additively manufacturing device configured to form the acoustic metamaterial such that the acoustic metamaterial comprises a first structure and the plurality of micro-resonators embedded within the first structure. Forming the acoustic metamaterial is performed such that an actual physical property of each of the plurality of micro-resonators is equal to a corresponding tuned physical property for each of the plurality of micro-resonators.

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.

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.

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.

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.

An acoustic metamaterial structure acts as a sound reducing filter in that the level of sound that exits the structure is much less than the magnitude of sound that enters the structure. In forming the structure, modular stages of a given geometry are stacked upon one another to create a cell. Each stage of the cell is provided with a nozzle that is acoustically connected to the nozzles of other stages of the cell. The stages have chambers that are positioned radially or laterally outside of the respective nozzles, with the chambers of the cell being acoustically connected to one another. An amalgamation of cells are arranged in an adjacent formation, with chambers of the cells being acoustically connected to one another for purposes of protecting items, components and people from destructive levels of sound. The geometry of the nozzles and chambers are designed for economical additive manufacture with acoustic infills.

An acoustic metamaterial structure acts as a sound reducing filter in that the level of sound that exits the structure is much less than the magnitude of sound that enters the structure. In forming the structure, modular stages of a given geometry are stacked upon one another to create a cell. Each stage of the cell is provided with a nozzle that is acoustically connected to the nozzles of other stages of the cell. The stages have chambers that are positioned radially or laterally outside of the respective nozzles, with the chambers of the cell being acoustically connected to one another. An amalgamation of cells are arranged in an adjacent formation, with chambers of the cells being acoustically connected to one another for purposes of protecting items, components and people from destructive levels of sound. The geometry of the nozzles and chambers are designed for economical additive manufacture with acoustic infills.