Other

3m Innovative Properties Company

Purdue Research Foundation

John Stuart Bolton

Jonathan H Alexander

Thomas P Hanschen

Paul A Martinson

Ronald W Gerdes

Thomas Herdtle

Thomas Heinrich Siegmund

Raymond J Cipra

Somesh Khandelwal

Seungkyu Lee

Heng-Yi Lai

Satya Surya Srinivas Varanasi

Srinivas Katragadda

Provided acoustic devices include an external housing defining an expansion chamber and a wall extending through and partitioning the expansion chamber into a central chamber and a peripheral chamber adjacent the central chamber, wherein an inlet and outlet communicate with the central chamber, and wherein the wall includes a plurality of apertures formed therethrough to allow air movement to and from the central and expansion chambers, the plurality of apertures sized to provide an average flow resistance ranging from 100 MKS Rayls to 5000 MKS Rayls. The acoustic devices advantageously show significant sound attenuation while streamlining air flow to reduce pressure drop across the expansion chamber.

Acoustic device

A cellular material barrier system for reducing sound transmission. The cellular material system includes a planar cellular metamaterial arrangement which includes at least one unit cell, the unit cell includes a sound normalizing arrangement, and a planar metamaterial arrangement coupled to the sound normalizing arrangement on a first side, the planar metamaterial arrangement includes a plate, and a frame affixed to the plate, the sound normalizing arrangement configured to normalize incident sound received at non-normal angle to thereby convey sound at normal angles to the planar metamaterial arrangement, the unit cell further comprising a back layer that is coupled to the sound normalizing arrangement on a second side, opposite the first side, the back layer is made from a porous material, including at least one of a fibrous layer, polymeric foams, ceramic foams, and metallic foams.

Sound barrier systems

A computer controlled method for predicting acoustical properties for a generally homogeneous porous material includes providing at least one prediction model for determining one or more acoustical properties of homogeneous porous materials, providing a selected prediction model for use in predicting acoustical properties for the generally homogeneous porous material, and providing an input set of at least microstructural parameters corresponding to the selection model. One or more macroscopic properties for the homogeneous porous material are determined based on the input set of the microstructural parameters and acoustical properties for the homogeneous porous material are generated as a function of the one or more macroscopic properties and the selected prediction model. Such a prediction method may be used to predict acoustical properties for a generally homogeneous limp fibrous material with use of a flow resistivity model for predicting flow resistivity of homogeneous limp fibrous materials based on an input set of microstructural parameters. Another computer controlled method for predicting acoustical properties of multiple component acoustical systems is provided which uses a transfer matrix process for determining acoustical properties of the system based at least in part on microstructural inputs provided for one or more components of the acoustical system.

Prediction and optimization method for homogeneous porous material and accoustical systems

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West Lafayette, IN, United States of America

John Stuart Bolton