3aSAb1. Specific damping capacity for high-loss materials.

Session: Wednesday Morning, May 15

Time: 10:45

Author: Gilbert F. Lee
Author: Bruce Hartmann
Location: Naval Surface Warfare Ctr., Silver Spring, MD 20903


The purpose of this presentation is to establish the relation between specific damping capacity and loss factor for high-loss materials. The motivation for this work is that the commonly used relationship between these variables is only valid for low-loss materials and leads to significant errors as the loss increases. The relationship cited in numerous references between specific damping capacity is (Delta)W/W=2(pi) tan(delta). This equation is only valid for very small values of (delta). Another difficulty with the above relationship is that the specific damping capacity is generally assumed to represent the fraction of energy converted to heat. For large values of tan (delta), (Delta)W/W can be greater than one, which seems to be a contradiction. In this presentation, a relationship between specific damping capacity and loss factor is derived, which is valid for all values of tan (delta). In the limit as the loss factor approaches infinity, the specific damping capacity approaches unity. A comparison of our relationship with others found in the literature will be presented. [Work supported by Naval Surface Warfare Center's In-house Laboratory Independent Research Program sponsored by the Office of Naval Research.]

from ASA 131st Meeting, Indianapolis, May 1996