Search results for "Viscoelasticity"
showing 4 items of 224 documents
A novel approach to nonlinear variable-order fractional viscoelasticity.
2020
This paper addresses nonlinear viscoelastic behaviour of fractional systems with variable time-dependent fractional order. In this case, the main challenge is that the Boltzmann linear superposition principle, i.e. the theoretical basis on which linear viscoelastic fractional operators are formulated, does not apply in standard form because the fractional order is not constant with time. Moving from this consideration, the paper proposes a novel approach where the system response is derived by a consistent application of the Boltzmann principle to an equivalent system, built at every time instant based on the fractional order at that instant and the response at all the previous ones. The ap…
Fractional viscoelastic transversally isotropic Timoshenko beam
2014
In this paper the viscoelastic behavior of pultruded beams has been examined. Pultruded beams are constituted by a polymer infilled with reinforcement in longitudinal direction, while in the orthogonal direction no fiber are present for technological reasons. As a consequence the material has two different behaviors in longitudinal and in orthogonal directions. It follows that pultruded beams are transversally isotropic, and the shear deformation may not be neglected. Based upon the previous observations and assuming for Creep and/or Relaxation test the power law, the constitutive equations are ruled by fractional operators. From constitutive laws, and assuming the Timoshenko beam theory to…
On the Dynamics of Fractional Visco-Elastic Beams
2012
With increasing advanced manufacturing process, visco-elastic materials are very attractive for mitigation of vibrations, provided that you may have advanced studies for capturing the realistic behavior of such materials. Experimental verification of the visco-elastic behavior is limited to some well-known low order models as the Maxwell or Kelvin models. However, both models are not sufficient to model the visco-elastic behavior of real materials, since only the Maxwell type can capture the relaxation tests and the Kelvin the creep tests, respectively. Very recently, it has been stressed that the most suitable model for capturing the visco-elastic behavior is the spring-pot, characterized …