Title

On a Theory of Complex Damping

Report Number

WL-TR-91-3078 Volume III, p. JCA-1 thru JCA-19

Creator

Liang, Z.

Lee, G. C.

Tong, M.

Corporate Author

State University of New York at Buffalo

Date

1991

Date Issued

1991-08

Extent

19

Identifier

ADA241313

Format

1 online resource

Abstract

In non-proportionally damped structures, both energy dlsslpatl.on and
energy transformation exist . To characterize such aspects, ln this paper,
a new concept of complex damping ratio is introduced by means of
generalizing the concept of Rayleigh quotient . The real part of this new
quantity is the traditionally defined damping ratio, which reflects the
modal energy dissipation per cycle; whereas, the imaginary part describes
a ratio of energy transformation of a virtual mode per cycle. With this
new concept, modal equations are set up and other relevant theoretical
results are developed. Such a theory of complex damping ls not only an
alternativeway to describe the phenomena of complex modes, but also a
useful tool, with strong physical meaning, for solving many theoretical
and engineering problems of non-proportionally damped systems.

Description

In non-proportionally damped structures, both energy dlsslpatl.on and
energy transformation exist . To characterize such aspects, ln this paper,
a new concept of complex damping ratio is introduced by means of
generalizing the concept of Rayleigh quotient . The real part of this new
quantity is the traditionally defined damping ratio, which reflects the
modal energy dissipation per cycle; whereas, the imaginary part describes
a ratio of energy transformation of a virtual mode per cycle. With this
new concept, modal equations are set up and other relevant theoretical
results are developed. Such a theory of complex damping ls not only an
alternativeway to describe the phenomena of complex modes, but also a
useful tool, with strong physical meaning, for solving many theoretical
and engineering problems of non-proportionally damped systems.

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)