### ASA 127th Meeting M.I.T. 1994 June 6-10

## 2aSA4. Spectral investigation of spatial scales associated with
substructures on a fluid-loaded plate.

**Kenneth A. Cunefare
**

**
W. Steve Shepard, Jr.
**

**
Jerry H. Ginsberg
**

**
**
*G. W. Woodruff School of Mech. Eng., Georgia Inst. of Technol., Atlanta,
GA 30332-0405
*

*
*
A wave-number-based formulation of the surface variational principle is
used to investigate the effects of substructures on fluid-loaded systems. The
paper examines issues of scale associated with the spatial distribution and
representation of substructure attachments. The primary emphasis is suspended
discrete spring-mass systems. A further extension considers an elastic beam
attached at multiple locations. The main structure is a simply supported plate
of infinite width contained in an infinite baffle and exposed to water on one
side. Scales are introduced to the formulation by using a spectral Fourier
series to represent point attachments. Previous work had considered the case
where line masses are fastened to the plate. The concept that evolved entailed
comparing the displacement and surface pressure obtained from analyses whose
only difference is the number of terms in the spectral series used to represent
the attached masses. The difference between such analyses is an indicator of
the significance of the scales associated with the additional terms in the
series. The work reported here increases the complexity of the system by
allowing for the masses to be flexibly attached to the plate. This generalized
problem is comparable to the types of systems considered to form fuzzy
structures. However, the viewpoint here is deterministic. Results to be
presented examine the influence of the scales associated with substructure
attachments when the parameters of the suspended substructures have a range of
values.