초록 ▼

A sound absorption device in accordance with this invention includes an enclosure loosely containing hollow beads. Preferably, the hollow beads have openings, and differ with respect to the volume of the hollow space defined by the walls of the beads, the wall thicknesses of the beads, the size of t

A sound absorption device in accordance with this invention includes an enclosure loosely containing hollow beads. Preferably, the hollow beads have openings, and differ with respect to the volume of the hollow space defined by the walls of the beads, the wall thicknesses of the beads, the size of the openings of the beads and/or the number of openings on the beads. Through Helmholtz resonance, vorticity and tortuous path scattering, the beads damp sound waves over a broad range of frequencies. Preferably, the beads are formed from a material able to withstand relatively high temperatures, such as ceramic or nickel. The beads can thus be used to damp sound in applications which generate significant heat in addition to sound, such as aircraft engines, rocket motors or other loud, heat-generating sources, for example. Also, by forming the beads from a material with a relatively low thermal conductivity, the beads can also be used for thermal insulation in addition to sound absorption.

대표청구항 ▼

[ I claim:] [1.] A device for receiving sound waves, the device comprising:a plurality of beads, wherein each said bead includesan outer wall defining a hollow space within the bead, andan opening in the outer wall, allowing the hollow space to acoustically communicate with space outside the bead;an

[ I claim:] [1.] A device for receiving sound waves, the device comprising:a plurality of beads, wherein each said bead includesan outer wall defining a hollow space within the bead, andan opening in the outer wall, allowing the hollow space to acoustically communicate with space outside the bead;an enclosure loosely containing the beads and including an interior space which acoustically communicates with the bead hollow spaces through the bead outer wall openings, the enclosure further including at least one inlet for allowing the interior space to acoustically communicate with a sound wave generating source which is exterior to said enclosure;wherein the enclosure allows the sound waves to travel through at least one inlet within the enclosure, through the bead outer wall openings, and into the hollow spaces within beads for damping sound waves which enter the enclosure; andwherein the hollow spaces among the plurality of beads differ in volume within a specified range to correspond to a predetermined frequency range of maximum sound absorption.