Accession Number : ADD017465

Title :   Acoustic Attenuation and Vibration Damping Materials.

Descriptive Note : Patent, Filed 25 Jan 94, patented 21 Mar 95,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Cushman, William B ; Thomas, Gerald B

Report Date : 21 Mar 1995

Pagination or Media Count : 12

Abstract : A means of enhancing the acoustic attenuation and vibration damping of a material by embedding high characteristic acoustic impedance particles, low characteristic acoustic impedance particles, or both high and low characteristic acoustic impedance particles within the matrix of the material is disclosed. The mass of the resultant material may be very low while retaining excellent acoustic attenuation, vibration damping, and structural characteristics. When particles with mis-matched characteristic acoustic impedances are embedded within the matrix of a material that can support shearing loads, propagating acoustic energy that encounters the particles of the instant invention is partially reflected in random directions. That is, the propagating energy is diffused. As the propagation vectors and modes of acoustic energy are effectively randomized, the probability of localized energy absorption and damping is increased. We present acoustic attenuation and vibration damping data for some representative examples of the instant invention and other commercially available materials.

Descriptors :   *STIFFENING, *MATRIX MATERIALS, *ACOUSTIC IMPEDANCE, *PATENTS, VIBRATION, STRUCTURAL PROPERTIES, ACOUSTIC WAVES, ENERGY, DAMPING, ORIENTATION(DIRECTION), PARTICLES, EMBEDDING, ACOUSTIC ATTENUATION, ENERGY ABSORBERS

Subject Categories : Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE