Search results for " Linear viscoelasticity"

showing 3 items of 3 documents

Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and Nor…

2013

The effects of time-dependent phenomena on concrete prestressed girder bridges are investigated. The study concerns the case of bridges built directly in their final configuration and that of bridges built by a sequence of stages in which geometry, restraints, and loads vary until the final configuration is achieved. An analytical approach based on the principles of aging linear viscoelasticity and the age-adjusted effective modulus method is followed. The paper has two aims: the first is to provide an efficient and simplified tool for the evaluation of the structural response in the early stages of design; the second is to compare the results of the analyses on actual cases of bridges when…

Engineeringbusiness.industryBuilding and ConstructionStructural engineeringCreepAging linear viscoelasticityViscoelasticitylaw.inventionSettore ICAR/09 - Tecnica Delle CostruzioniPrestressed concreteCreepStructural loadPrediction modelDeflection (engineering)lawSegmental bridgeGirderBending momentShrinkagebusinessConcreteCivil and Structural EngineeringShrinkageJournal of Bridge Engineering

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Fractional characteristic times and dissipated energy in fractional linear viscoelasticity

2016

Abstract In fractional viscoelasticity the stress–strain relation is a differential equation with non-integer operators (derivative or integral). Such constitutive law is able to describe the mechanical behavior of several materials, but when fractional operators appear, the elastic and the viscous contribution are inseparable and the characteristic times (relaxation and retardation time) cannot be defined. This paper aims to provide an approach to separate the elastic and the viscous phase in the fractional stress–strain relation with the aid of an equivalent classical model (Kelvin–Voigt or Maxwell). For such equivalent model the parameters are selected by an optimization procedure. Once …

Numerical AnalysisDifferential equationApplied MathematicsMathematical analysisConstitutive equationLoss and storage modulusStiffnessDissipated energy Fractional calculus in linear viscoelasticity Fractional creep and relaxation times Loss and storage modulusHarmonic (mathematics)02 engineering and technologyDissipationDissipated energy021001 nanoscience & nanotechnologyViscoelasticityViscosity020303 mechanical engineering & transports0203 mechanical engineeringModeling and SimulationmedicineRelaxation (physics)Fractional creep and relaxation timemedicine.symptom0210 nano-technologyFractional calculus in linear viscoelasticityMathematics

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Evaluation of the temperature effect on the fractional linear viscoelastic model for an epoxy resin

2016

The paper deals with the evolution of the parameters of a fractional model for different values of temperature. An experimental campaign has been performed on epoxy resin at different levels of temperature. It is shown that epoxy resin is very sensitive to the temperature.

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