Identification of Viscoelastic Vibration Absorbers in a Frequency Band

The behavior of viscoelastic materials under the action of dynamic loads exhibits characteristics that cannot be modeled in terms of the classical Hooke's Law. Usually a complex modulus (that depends on the load frequency) is adopted for expressing the relationship between stress and strain. From this complex modulus, it is possible to determine two other characterization parameters, namely the storage modulus and the loss factor. By knowing the frequency response, it is possible to determine the stiffness of a longitudinal viscoelastic vibration absorber together with its loss factor. By using the shape factor of the viscoelastic element, the storage modulus of the material can also be obtained. The present contribution presents an experimental procedure for the determination of the parameters used to characterize viscoelastic absorbers in a given frequency range. The resulting characterization of the vibration absorber can be used in the design of vibration reduction devices, including those for rotating machinery applications as it is shown in the remaining of this article.