Active and Passive Vibration Damping

3Characterization of the Properties of Viscoelastic Materials

3.1 Introduction

Characterization of the mechanical behavior of viscoelastic materials (VEMs) is essential to the proper design of effective damping treatments that are suitable for attenuating structural vibrations over a particular range of operating temperatures and frequencies. This chapter presents the behavior of typical VEMs as well as the important techniques for characterizing the mechanical properties of this class of materials both in the frequency and time domains. The principles of “time‐frequency” and “time‐temperature” superposition are introduced. These principles are applied to generate the widely used “master curves” that constitute the unified means and the industry norm for presenting the damping properties of VEMs.

3.2 Typical Behavior of Viscoelastic Materials

The behavior of typical VEMs depends primarily on the operating temperature, and frequency. Figure 3.1 displays the effect of temperature on the storage modulus and loss factor of most VEMs.

Figure 3.1 Effect of temperature on the storage modulus and loss factor of viscoelastic materials at constant frequency.

The figure indicates that the behavior of the VEM varies drastically over three distinct temperature regions. At the low temperature region, that is, the “glassy region,” the VEM behaves like glass where the storage modulus assumes ...