Estimation Of Nonproportional Damping From Experimental Measurements

Item

Title
Estimation Of Nonproportional Damping From Experimental Measurements
Report Number
WL-TR-91-3078 Volume III, p. JAB-1
Creator
Hasselman, T. K.
Chrostowski, Jon D.
Corporate Author
Engineering Mechanics Associates, Inc.
Date
1991
Date Issued
1991-08
Extent
1
Identifier
ADA241313
Format
1 online resource
Abstract
The ftill modal damping matrix (both diagonal and off-diagonal terms) is required
to synthesize the modal damping of a structural system from substructure tests,
and may be used to estimate the distribution of damping in a structure.
A method for determining a full modal damping matrix from experimental measurements
was published by the first author in 1972. The method was applied with
limited success, the problem being that complex modes were very difficult to obtain
from the analog sine-dwell modal test data which were available at the time.
Since then, several modal identification methods have been developed which derive
complex modes from digitally recorded and processed vibration test data. Only the
real parts of these complex modes are used, however; the small imaginary parts so
far have been ignored.
This paper presents methods which have been developed to condition the experimental
complex mode data obtained by the ERA method for purposes of estimating
the full modal damping matrix. Practical application of these methods using experimental
data from truss-beam type structures are presented.
FULL PAPER NOT AVAILABLE FOR
PUBLICATION
Description
The ftill modal damping matrix (both diagonal and off-diagonal terms) is required
to synthesize the modal damping of a structural system from substructure tests,
and may be used to estimate the distribution of damping in a structure.
A method for determining a full modal damping matrix from experimental measurements
was published by the first author in 1972. The method was applied with
limited success, the problem being that complex modes were very difficult to obtain
from the analog sine-dwell modal test data which were available at the time.
Since then, several modal identification methods have been developed which derive
complex modes from digitally recorded and processed vibration test data. Only the
real parts of these complex modes are used, however; the small imaginary parts so
far have been ignored.
This paper presents methods which have been developed to condition the experimental
complex mode data obtained by the ERA method for purposes of estimating
the full modal damping matrix. Practical application of these methods using experimental
data from truss-beam type structures are presented.
FULL PAPER NOT AVAILABLE FOR
PUBLICATION
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 (GCA-1 through JCB-17)
Media
articleJAB

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Items with "Has Part: Estimation Of Nonproportional Damping From Experimental Measurements"
Title Class
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (GCA-1 through JCB-17)