@article{SvaneborgKarimiVarzanehHojdisetal.2016,
  author    = {Svaneborg, Carsten and Karimi-Varzaneh, Hossein Ali and Hojdis, Nils and Fleck, Franz and Everaers, Ralf},
  title     = {Multiscale approach to equilibrating model polymer melts},
  series = {Physical Review E},
  volume    = {94},
  journal   = {Physical Review E},
  number    = {032502},
  publisher = {AIP Publishing},
  address   = {Melville, NY},
  issn      = {2470-0053},
  doi       = {10.1103/PhysRevE.94.032502},
  year      = {2016},
  abstract  = {We present an effective and simple multiscale method for equilibrating Kremer Grest model polymer melts of varying stiffness. In our approach, we progressively equilibrate the melt structure above the tube scale, inside the tube and finally at the monomeric scale. We make use of models designed to be computationally effective at each scale. Density fluctuations in the melt structure above the tube scale are minimized through a Monte Carlo simulated annealing of a lattice polymer model. Subsequently the melt structure below the tube scale is equilibrated via the Rouse dynamics of a force-capped Kremer-Grest model that allows chains to partially interpenetrate. Finally the Kremer-Grest force field is introduced to freeze the topological state and enforce correct monomer packing. We generate 15 melts of 500 chains of 10.000 beads for varying chain stiffness as well as a number of melts with 1.000 chains of 15.000 monomers. To validate the equilibration process we study the time evolution of bulk, collective, and single-chain observables at the monomeric, mesoscopic, and macroscopic length scales. Extension of the present method to longer, branched, or polydisperse chains, and/or larger system sizes is straightforward.},
  language  = {en}
}
@article{SchwabHojdisLacayoetal.2016,
  author    = {Schwab, Lukas and Hojdis, Nils and Lacayo, Jorge and Wilhelm, Manfred},
  title     = {Fourier-Transform Rheology of Unvulcanized, Carbon Black Filled Styrene Butadiene Rubber},
  series = {Macromolecular Materials and Engineering},
  volume    = {301},
  journal   = {Macromolecular Materials and Engineering},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1439-2054},
  doi       = {10.1002/mame.201500356},
  pages     = {457 -- 468},
  year      = {2016},
  abstract  = {Rubber materials filled with reinforcing fillers display nonlinear rheological behavior at small strain amplitudes below γ0 < 0.1. Nevertheless, rheological data are analyzed mostly in terms of linear parameters, such as shear moduli (G′, G″), which loose their physical meaning in the nonlinear regime. In this work styrene butadiene rubber filled with carbon black (CB) under large amplitude oscillatory shear (LAOS) is analyzed in terms of the nonlinear parameter I3/1. Three different CB grades are used and the filler load is varied between 0 and 70 phr. It is found that I3/1(φ) is most sensitive to changes of the total accessible filler surface area at low strain amplitudes (γ0 = 0.32). The addition of up to 70 phr CB leads to an increase of I3/1(φ) by a factor of more than ten. The influence of the measurement temperature on I3/1 is pronounced for CB levels above the percolation threshold.},
  language  = {en}
}
@article{HarishWriggersJungketal.2016,
  author    = {Harish, Ajay B. and Wriggers, Peter and Jungk, Juliane and Hojdis, Nils and Recker, Carla},
  title     = {Mesoscale Constitutive Modeling of Non-Crystallizing Filled Elastomers},
  series = {Computational Mechanics},
  volume    = {57},
  journal   = {Computational Mechanics},
  publisher = {Springer},
  address   = {Berlin},
  issn      = {1432-0924},
  doi       = {10.1007/s00466-015-1251-1},
  pages     = {653 -- 677},
  year      = {2016},
  abstract  = {Elastomers are exceptional materials owing to their ability to undergo large deformations before failure. However, due to their very low stiffness, they are not always suitable for industrial applications. Addition of filler particles provides reinforcing effects and thus enhances the material properties that render them more versatile for applications like tyres etc. However, deformation behavior of filled polymers is accompanied by several nonlinear effects like Mullins and Payne effect. To this day, the physical and chemical changes resulting in such nonlinear effect remain an active area of research. In this work, we develop a heterogeneous (or multiphase) constitutive model at the mesoscale explicitly considering filler particle aggregates, elastomeric matrix and their mechanical interaction through an approximate interface layer. The developed constitutive model is used to demonstrate cluster breakage, also, as one of the possible sources for Mullins effect observed in non-crystallizing filled elastomers.},
  language  = {en}
}