A viscoelastic-viscoplastic constitutive model for glassy polymers informed by molecular dynamics simulations

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:226

Article

Zhao, Wuyang¹  Ries, Maximilian¹  Steinmann, Paul¹  Pfaller, Sebastian¹ 

[1] Friedrich Alexander Univ Erlangen Nurnberg, Inst Appl Mech, Egerlandstr 5, D-91058 Erlangen, Germany

关键词: Constitutive model;    Glassy polymers;    Viscoelasticity;    Viscoplasticity;    Molecular dynamics;   

DOI  :  10.1016/j.ijsolstr.2021.111071

来源: Elsevier

【 摘 要 】

This contribution presents a phenomenological viscoelastic-viscoplastic constitutive model informed by coarse-grained (CG) molecular dynamics (MD) simulations of pure glassy polystyrene (PS). In contrast to experiments, where viscoplasticity is caused by various effects simultaneously, these effects can be decomposed in MD simulations by adjusting the MD system. In the MD simulations considered here, neither bond breakage nor cross-links are introduced; instead, we focus on the intermolecular interaction of polymer chains. We employ a thermo-dynamically consistent generalized Maxwell framework parallelly comprising an elastic, a viscoelastic, and several elasto-viscoplastic modules with different yield stress to capture the viscoelastic and the viscoplastic mechanical behavior simultaneously. The yield stresses decrease with the maximum deformation the MD system has experienced. The constitutive model presented here is based on 10 material parameters, which can be identified by a few data sets and fits well the CG MD simulations of PS under uniaxial and biaxial deformation with time-proportional and cyclic loading conditions in a wide range of strain rates (0.1%/ns-20%/ns). (c) 2021 Elsevier Ltd. All rights reserved.

【 授权许可】

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