An acoustic element includes a nanovoided polymer layer having a first nanovoid topology in an unactuated state and a second nanovoid topology different than the first nanovoid topology in an actuated state. Capacitive actuation of the nanovoided polymer layer, for instance, can be used to reversibly control the size and shape of the nanovoids within the polymer layer and hence tune its sound damping characteristics or sound transduction behavior, e.g., during operation of the acoustic element. An acoustic element may be configured for passive or active sound attenuation. Various other apparatuses, systems, materials, and methods are also disclosed.

Aspects are disclosed of a filler for occupying a volume. The filler includes an expandable filler positioned in the volume so that it occupies a percentage of the volume. The expandable filler can permanently expand from a first dimension to a second dimension upon the application of an expansion trigger. The filler also includes an acoustic filler made up of a plurality of acoustically active beads positioned with the expandable filler in the volume so that the acoustic filler can adsorb gas flowing into the volume. Other embodiments are disclosed and claimed.

An acoustic material system (12) has a matrix of material (14) supporting a plurality of evenly spaced and non-evenly spaced wave scatterer elements (16 and 18) of different density. The matrix (14) may consist of poro-elastic materials. The wave scattering elements (16 and 18) may consist of masses of different shapes and sizes. Microporous sheets may be utilized in layers between matrices (14). The holes (32) formed in the sheets (28) may be of different sizes, shapes, and may have three-dimensional profile, such as a conical shape (50).

An acoustic material system (12) has a matrix of material (14) supporting a plurality of evenly spaced and non-evenly spaced wave scatterer elements (16 and 18) of different density. The matrix (14) may consist of poro-elastic materials. The wave scattering elements (16 and 18) may consist of masses of different shapes and sizes. Microporous sheets may be utilized in layers between matrices (14). The holes (32) formed in the sheets (28) may be of different sizes, shapes, and may have three-dimensional profile, such as a conical shape (50).

Aspects are disclosed of a filler for occupying a volume. The filler includes an expandable filler positioned in the volume so that it occupies a percentage of the volume. The expandable filler can permanently expand from a first dimension to a second dimension upon the application of an expansion trigger. The filler also includes an acoustic filler made up of a plurality of acoustically active beads positioned with the expandable filler in the volume so that the acoustic filler can adsorb gas flowing into the volume. Other embodiments are disclosed and claimed.

An acoustic sound absorptive panel or block is provided that is made from a plurality of materials and volumes selected such that each discrete volume of material has a sufficiently different sound absorption profile, resulting in a system that provides better overall sound absorption of traffic noise from motorways and railways in a practical and cost-efficient manner.

An acoustic sound absorptive panel or block is provided that is made from a plurality of materials and volumes selected such that each discrete volume of material has a sufficiently different sound absorption profile, resulting in a system that provides better overall sound absorption of traffic noise from motorways and railways in a practical and cost-efficient manner.

Disclosed are a method for preparing a sound-absorbing member and a sound-absorbing member. The method for preparing a sound-absorbing member includes: providing non-foaming sound-absorbing material powder and a foaming material; uniformly mixing the non-foaming sound-absorbing material powder with the foaming material and adding an auxiliary to form a sound-absorbing mixture; and foaming the sound-absorbing mixture to form foam with cells, wherein the non-foaming sound-absorbing material powder adheres to a surface and the cells of the foam. The foamed sound-absorbing material powder and the foam constitute a sound-absorbing member.

Disclosed are a method for preparing a sound-absorbing member and a sound-absorbing member. The method for preparing a sound-absorbing member includes: providing non-foaming sound-absorbing material powder and a foaming material; uniformly mixing the non-foaming sound-absorbing material powder with the foaming material and adding an auxiliary to form a sound-absorbing mixture; and foaming the sound-absorbing mixture to form foam with cells, wherein the non-foaming sound-absorbing material powder adheres to a surface and the cells of the foam. The foamed sound-absorbing material powder and the foam constitute a sound-absorbing member.

An acoustic absorbing filler, the acoustic absorbing filler comprising agglomerates comprising a first phase comprising a plurality of porous particulates and a second phase comprising a binder; wherein the acoustic absorbing filler has a median sieved particle size of from 100 micrometer to 700 micrometers and a specific surface area of from 50 m.sup.2/g to 900 m.sup.2/g; wherein the acoustic absorbing filler has a normal incidence acoustic absorption of no less than 0.20 alpha at 400 Hz.