## 5pSA6. Continuous structures as ``fuzzy'' substructures.

### Session: Friday Afternoon, May 17

### Time: 3:20

**Author: M. Strasberg**

**Location: David Taylor Model Basin, NSWC, Bethesda, MD 20084-5000**

**Abstract:**

It is by now well known that the resistive part of the combined
driving-point impedance of a collection of sprung masses with closely spaced
frequencies of antiresonance can be expressed by the simple relation
R=1/2(pi)[sup 2]f[sup 2]m[inf 0], where m[inf 0] is the resonant mass density,
defined so that m[inf 0]df is the combined mass of the sprung masses in
antiresonance in a differential frequency band of width df centered at the
cyclic driving frequency f. To apply this relation to a continuous or
complicated structure, it is necessary to determine how the value of m[inf 0]
varies with frequency for a set of sprung masses duplicating the driving-point
impedance of the structure. The procedure is illustrated by calculating m[inf 0]
for several simple continuous structures, including a long uniform rod in axial
vibration, and a long uniform beam or large thin plate in flexural vibration.
The values of resistance obtained by treating these systems as fuzzy structures
agree with well-known values.

from ASA 131st Meeting, Indianapolis, May 1996