Impedance Matched Mass-Dampers: A New Approach For Improving Structural Damping

Item

Title
Impedance Matched Mass-Dampers: A New Approach For Improving Structural Damping
Report Number
WL-TR-91-3078 Volume I, p. DAA-1 thru DAA-20
Creator
Gardner, Craig
Lyon, Richard H.
Corporate Author
General Eletric-Power Generation
Massachusetts Institute of Technology
Laboratory
Wright Laboratory
Date
1991
Date Issued
1991-08
Extent
20
Contract
Laboratory Research - No Contract
DoD Project
2401
DoD Task
240104
Identifier
ADA241311
Format
1 online resource
Abstract
Statistical Energy Analysis (SEA) techniques are used to analytically determine the damping effect achieved by attaching a quantity of mass-dampers to a damped flat plate. Mass-dampers are defined as SDOF oscillators which are over damped and have a resonant frequency below the frequency range of interest. The analysis has shown that the damping effect achieved by this approach is maximized when damper impedance is matched to a particular ratio of the average drive point impedance of the plate. The analysis indicates that the damping effect achieved is significant for mass-damper mass to plate mass ratios as low as 0.05 to 0.2. A prototype mass-damper system was designed and tested to verify the analytical results. The experimental results showed that significant improvements in damping were achieved and that the amplitude of modal frequencies were reduced by as much as 10-15 dB over a wide frequency range. This approach differs from visco-elastic techniques in that it does not share strain energy with base structure. This characteristic may make this approach ·effective for damping stiff structures at low frequencies.
Description
Statistical Energy Analysis (SEA) techniques are used to analytically determine the damping effect achieved by attaching a quantity of mass-dampers to a damped flat plate. Mass-dampers are defined as SDOF oscillators which are over damped and have a resonant frequency below the frequency range of interest. The analysis has shown that the damping effect achieved by this approach is maximized when damper impedance is matched to a particular ratio of the average drive point impedance of the plate. The analysis indicates that the damping effect achieved is significant for mass-damper mass to plate mass ratios as low as 0.05 to 0.2. A prototype mass-damper system was designed and tested to verify the analytical results. The experimental results showed that significant improvements in damping were achieved and that the amplitude of modal frequencies were reduced by as much as 10-15 dB over a wide frequency range. This approach differs from visco-elastic techniques in that it does not share strain energy with base structure. This characteristic may make this approach ·effective for damping stiff structures at low frequencies.
Distribution Classification
1
Distribution Conflict
No
DTIC Record Exists
No
Illinois Tech Related
No
Photo Quality
Not Needed
Report Availability
Full text available
Type
article
Is Part Of
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (Pages AAC-1 through DCC-19)
Media
article23