Multiple-Sprung Masses for Wideband Noise Control.
Abstract
The design of a wide frequency band neutralizer, vibration absorber and/or structural fuzzy, in the form of multiple sprung masses, is extensively reported in the open literature. The action of the device is reported in terms of the joint point impedance of the sprung masses. This joint impedance is merely the sum over the impedances of the individual sprung masses at the common point to which the device is to be attached to a master structure. The normalized frequency bandwidth of a device composed of a single sprung mass is proportional to the loss factor of that sprung mass. To increase this bandwidth, a device composed of more than one sprung mass is utilized. The multiplicity of sprung masses with distributed resonance frequencies is the scheme by which a wide frequency band is attained. To keep the undulations in the joint impedance of a set composed of a multiplicity of sprung masses suppressed, the loss factors are rendered larger than the normalized separations between adjacent anti-resonance frequencies. This modal overlap condition, together with the conservation of weight, are central to the design of the device.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 31, 1998
- Accession Number
- ADA354042
Entities
People
- Gideon Maidanik
- K. Becker
Organizations
- Naval Surface Warfare Center Carderock Division