Nanocomposite behaviour during tensile deformation?

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Influence of filler properties on the mechanical failure of a polymer nanocomposite A. Kutvonen , G. Rossi , T. Ala-Nissil Multiscale Statistical Physics Group at COMP/Aalto. Polymer nanocomposites have a wide range of applications varying from car tyres to advanced coating technologies - PowerPoint PPT Presentation

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<ul><li><p>Influence of filler properties on the mechanical failure of a polymer nanocompositeA. Kutvonen , G. Rossi , T. Ala-NissilMultiscale Statistical Physics Group at COMP/Aalto Polymer nanocomposites have a wide range of applications varying from car tyres to advanced coating technologies</p><p> How do parameters such as loading, filler material and topology influence the nanocomposite mechanical properties?Nanocomposite behaviour during tensile deformation?</p></li><li><p> Molecular dynamics simulationsV(r) -&gt; F(r) -&gt; move -&gt;V(r)</p><p> Bead-spring model for polymers+ Lennard Jones (LJ) potentials</p><p> Periodic boundary conditions</p><p> Fillers with different topologies, masses and sizesMODEL &amp; METHODS</p></li><li><p>how much system resist strain System equilibrated in NVT ensemble above glass transition temperature</p><p> Walls are moved with constant velocity METHODS &amp; STRESS STRAIN CURVESStrainStressElastic responseYield pointCavitationBig cavityStress-Strain curve-Indicates how system resists strain</p></li><li><p>RESULTS 1/3 WHERE DOES THE STRENGTH COME FROM?All neighboursAll neighboursBead-bead neighboursFiller-filler neighboursStrainStress9Bead-filler neighboursAll neighboursNumberFractionFractionFraction Before yield point the density of system is decreasingNumber of contacts reduces</p><p> Fraction bead-filler neighbours is increasing</p></li><li><p>RESULTS 2/3 Fixed volume loading Size comparison Smaller fillers increase yield stress for cavitation</p><p> Is it because smaller fillers in total have a larger surface area? No, even with constant surface area the smallest win</p><p> Smaller ones have better mobility</p></li><li><p>RESULTS 3/3 &amp; WORK IN PROGRESS Same number of fillers and same massvs. Triangles might have more rigid behaviour Study of the effects of: Mass of the filler Loading Stick and sheet shaped fillers BranchingIN PROGRESS:</p></li><li><p>Thank you for your attention!</p></li><li><p>MD SIMULATION PROTOCOLDecompress and find equilibrium volume in microcanonical ensembleRandomize initial positions and compressEquilibration by annealingPull walls with constant velocity and gather data</p></li></ul>

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