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245 1 0 _aAnomalous moisture diffusion in viscoelastic polymers: modeling and testing
490 0 _vJournal of Applied Mechanics, 67(2), p.391-396, 2000
520 3 _aIt is now well known that Fick's Law is frequently inadequate for describing moisture diffusion in polymers or polymer composites. Non-Fickian or anomalous diffusion typically occurs when the rates of diffusion and viscoelastic relaxation in a polymer are comparable, and the ambient temperature is below the glass transition temperature (Tg)of the polymer. As a result, it is necessary to take into account the time-dependent response of a polymer, analogous to viscoelastic relaxation of mechanical properties, in constructing such a model. In this paper, a simple yet robust methodology is proposed that would allow characterization of non-Fickian diffusion coefficients from moisture weight gain data for a polymer below its Tg. Subsequently, these diffusion coefficients are used for predicting moisture concentration profiles through the thickness of a polymer. Moisture weight gain data at different temperatures for an epoxy adhesive is employed to calibrate the model. Specimen thickness independence of the modeling parameters is established through comparison with test data. A finite element procedure that extends this methodology to more complex shapes and boundary conditions is also validated.
650 1 4 _aBOUNDARY CONDITIONS
650 1 4 _aCOMPUTER SIMULATION
650 1 4 _aDIFFUSION IN SOLIDS
650 1 4 _aFINITE ELEMENT METHOD
650 1 4 _aGLASS TRANSITION
650 1 4 _aMATHEMATICAL MODELS
650 1 4 _aMOISTURE
650 1 4 _aNUMERICAL ANALYSIS
650 1 4 _aRELAXATION PROCESSES
650 1 4 _aTEMPERATURE
650 1 4 _aVISCOELASTICITY
700 1 2 _aRoy, S.
700 1 2 _aXu, W.X.
700 1 2 _aPark, S.J.
700 1 2 _aLiechti, K.M.
856 4 0 _uhttps://drive.google.com/file/d/1HoOBpuXtb_u5XKKGTSArErkOKC7a4x79/view?usp=drivesdk
_zPara ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx
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