Affiliations: Departamento de Engenharia Mecânica, PUC-Rio, Rua
Marquês de São Vicente 225, 22453-900, Rio de Janeiro, Brazil. Tel.:
+55 21 3114 1178; Fax: +55 21 3314 1165; E-mail: beto_cm@yahoo.com;
trindade@mec.puc-rio.br; rsampaio@mec.puc-rio.br
Abstract: Even though there is a growing interest in active vibration
isolation systems, passive approaches are still the best choice in many cases
because they are inherently the simplest and of lowest cost. Moreover, better
comprehension of the dynamics and specially of the damping behavior in passive
systems is required for successful implementation of active schemes. In the
vast literature of passive isolation systems, there are not many works that
consider damping models more elaborated than the widely used complex modulus.
In this work a passive isolation system composed of a base and two isolators,
modelled as Timoshenko beams, and a vibration source, modelled as a rigid body,
is considered. For the isolators, two different viscoelastic models are
considered: the Anelastic Displacement Fields (ADF) and Fractional Calculus
(FC), which will be compared with the complex modulus model. The results show
that both ADF and FC models lead to better approximation of dissipated energy,
since they account for frequency-dependence of the viscoelastic isolators.
Analysis of the curve-fitting of material parameters, using ADF and FC models
has shown that generally less parameters are needed by FC model, for the same
fitting quality, although optimization results depends strongly on the initial
guess for the solution.
Keywords: viscoelastic models, vibration isolation, power flow
