Search results for "Fractional viscoelasticity"

showing 3 items of 13 documents

The finite element implementation of 3D fractional viscoelastic constitutive models

2018

Abstract The aim of this paper is to present the implementation of 3D fractional viscoelastic constitutive theory presented in Alotta et al., 2016 [1]. Fractional viscoelastic models exactly reproduce the time dependent behaviour of real viscoelastic materials which exhibit a long “fading memory”. From an implementation point of view, this feature implies storing the stress/strain history throughout the simulations which may require a large amount of memory. We propose here a number of strategies to effectively limit the memory required. The form of the constitutive equations are summarized and the finite element implementation in a Newton-Raphson integration scheme is described in detail. …

RelaxationComputer scienceSubroutineConstitutive equation3D constitutive models; Creep; Fractional viscoelasticity; Numerical modelling; Relaxation; Analysis; Engineering (all); Computer Graphics and Computer-Aided Design; Applied Mathematics02 engineering and technologyViscoelasticityStress (mechanics)Engineering (all)0203 mechanical engineeringFractional viscoelasticityApplied mathematicsLimit (mathematics)Applied MathematicsGeneral EngineeringAnalysiCreep021001 nanoscience & nanotechnologyComputer Graphics and Computer-Aided DesignFinite element method020303 mechanical engineering & transportsNumerical modellingBenchmark (computing)3D constitutive model0210 nano-technologyAnalysisQuasistatic process
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On the behavior of a three-dimensional fractional viscoelastic constitutive model

2016

In this paper a three-dimensional isotropic fractional viscoelastic model is examined. It is shown that if different time scales for the volumetric and deviatoric components are assumed, the Poisson ratio is time varying function; in particular viscoelastic Poisson ratio may be obtained both increasing and decreasing with time. Moreover, it is shown that, from a theoretical point of view, one-dimensional fractional constitutive laws for normal stress and strain components are not correct to fit uniaxial experimental test, unless the time scale of deviatoric and volumetric are equal. Finally, the model is proved to satisfy correspondence principles also for the viscoelastic Poisson’s ratio a…

Scale (ratio)Mechanical EngineeringConstitutive equationMathematical analysisIsotropy02 engineering and technologyFunction (mathematics)021001 nanoscience & nanotechnologyCondensed Matter PhysicsPoisson distributionViscoelasticityPoisson's ratioCondensed Matter::Soft Condensed Mattersymbols.namesake020303 mechanical engineering & transports0203 mechanical engineeringMechanics of MaterialsConsistency (statistics)symbolsFractional viscoelasticity 3D constitutive models Creep Relaxation Viscoelastic Poisson ratio0210 nano-technologyMathematicsMeccanica
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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…

timoshenko beamTimoshenko beam theoryMaterials sciencebusiness.industryDifferential equationIsotropyConstitutive equationStructural engineeringMechanicsfractional viscoelasticityPower lawViscoelasticityCreepPhysics::Accelerator PhysicsbusinessBeam (structure)ICFDA'14 International Conference on Fractional Differentiation and Its Applications 2014
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