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

## 4aSA6. Structural acoustic analysis of structures with frequency-dependent
damping treatments.

**Gordon C. Everstine
**

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Raymond S.-C. Cheng
**

**
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*Comput. Mech. Office, David Taylor Model Basin, Carderock Div., Naval
Surface Warfare Ctr., Bethesda, MD 20084-5000
*

*
*
An approach is described for computing the direct frequency response of
structural acoustic systems containing frequency-dependent materials or damping
treatments. The frequency dependence of the damping material is treated by
approximating its modulus with a second-order polynomial so that the
stiffnesses associated with the constant, linear, and quadratic terms can be
combined with the stiffness, damping, and mass matrices assembled for the rest
of the structure. The mathematically complex stiffness, damping, and mass
matrices that result can then be used in coupled finite element/boundary
element structural acoustic analyses using a direct frequency sweep.