### ASA 126th Meeting Denver 1993 October 4-8

## 2aSA2. Resonance apparatus for characterization of viscoelastic materials.

**Bruce Hartmann
Gilbert F. Lee
John D. Lee
**

**
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*Polymer Sci. Group, Naval Surface Warfare Ctr., Silver Spring, MD
20903-5640
*

*
*
A resonance apparatus for the characterization of viscoelastic materials
will be described. Measurements have been made of modulus values as low as 0.1
MPa and as high as 70 GPa and loss factors from 0.003 to 2.5. Material
properties are determined as exact (numerical) solutions of the wave equation
with no simplifying assumptions. In particular, the loss factor is not
calculated from the half-power point and is valid for large values of loss
factor. By bonding the sample to the driver, clamping errors common with other
instruments are eliminated. For any given measurement temperature, the
frequency range of the measurements is about 1.5 decades centered at about 1
kHz. Depending on the sample length and modulus, data can be obtained from 100
Hz to 25 kHz. Once measurements have been made as a function of temperature,
the data are shifted to form a master curve and fitted to an analytical model.
Illustrative data will be presented for a high-loss and a low-loss
polyurethane. [This work was sponsored by the Independent Research Program of
the Naval Surface Warfare Center.]