ABSTRACT
All materials and, hence, structures contain damping. For applications where sound and vibration are present, increased damping is desired to attenuate the unwanted vibration. However, in other applications, such as rolling wheels and belt-drive systems, high levels of damping are undesired. Although the primary focus of this section is to look at situations where damping is desired, the same analysis and application principles apply to systems in which damping is detrimental to performance. Metallic materials often have very low levels of damping. Typically, the loss modulus is on the order of 0.1% to 1.0 % of the storage modulus. However, polymeric materials typically have loss moduli in the range of 1% to 200 % of the storage moduli. Thus, a polymeric or polymeric composite material will damp vibration much more effectively than does a metallic material.
