TY - JOUR

T1 - Effect of temperature on the viscoelastic damage behaviour of nanoparticle/epoxy nanocomposites

T2 - Constitutive modelling and experimental validation

AU - Unger, Robin

AU - Arash, Behrouz

AU - Exner, Wibke

AU - Rolfes, Raimund

N1 - Funding Information: We would like to thank Ricarda Berger and Benedikt Hofmeister for their expertise and support with respect to the parameter identification/optimisation process. The authors acknowledge the support of the LUIS scientific computing cluster, which is funded by Leibniz Universität Hannover, the Lower Saxony Ministry of Science and Culture (MWK) and the DFG. This work originates from two research projects: (1) "Hybrid laminates and nanoparticle-reinforced materials for improved rotor blade structures" ("LENAH - Lebensdauererh?hung und Leichtbauoptimierung durch nanomodifizierte und hybride Werkstoffsysteme im Rotorblatt"), funded by the Federal Ministry of Education and Research of Germany, and (2) "Challenges of industrial application of nano-modified and hybrid material systems in lightweight rotor blade construction" ("HANNAH - Herausforderungen der industriellen Anwendung von nanomodifizierten und hybriden Werkstoffsystemen im Rotorblattleichtbau"), funded by the Federal Ministry for Economic Affairs and Energy. The authors wish to express their gratitude for the financial support.

PY - 2020/3/16

Y1 - 2020/3/16

N2 - The accurate prediction of the complex material response of nanoparticle/epoxy nanocomposites for thermomechanical load cases is of great interest for engineering applications. In the present work, three main contributions with respect to multi-scale modelling of the viscoelastic damage behaviour of nanocomposites are presented. Firstly, a constitutive model for the viscoelastic damage behaviour at finite temperatures below the glass-transition temperature is proposed. The constitutive model captures the main characteristics of the material response including the non-linear hyperelasticity, softening behaviour and the effect of temperature. Secondly, the material model is calibrated using purely experimental results to evaluate the best capability of the model in reproducing the stress–strain response at different strain rates and temperatures. The calibrated model predicts the material behaviour across a range of nanoparticle weight fractions with good agreement with experimental results. Finally, a combined approach of experimental testing and molecular simulations is proposed to identify the parameters of the constitutive model. This study shows that the proposed simulation-based framework can be used to significantly reduce the number of experimental tests required for identification of material parameters without a significant loss of accuracy in the material response prediction. The predictive capability of the atomistically calibrated constitutive model is validated, with additional experimental results not used within the parameter identification, in terms of an accurate representation of the viscoelastic damage behaviour of nanoparticle/epoxy nanocomposites at finite temperatures. The present study underlines the capabilities of numerical molecular simulations intended for the characterisation of material properties with respect to physically based constitutive modelling and multi-scale approaches.

AB - The accurate prediction of the complex material response of nanoparticle/epoxy nanocomposites for thermomechanical load cases is of great interest for engineering applications. In the present work, three main contributions with respect to multi-scale modelling of the viscoelastic damage behaviour of nanocomposites are presented. Firstly, a constitutive model for the viscoelastic damage behaviour at finite temperatures below the glass-transition temperature is proposed. The constitutive model captures the main characteristics of the material response including the non-linear hyperelasticity, softening behaviour and the effect of temperature. Secondly, the material model is calibrated using purely experimental results to evaluate the best capability of the model in reproducing the stress–strain response at different strain rates and temperatures. The calibrated model predicts the material behaviour across a range of nanoparticle weight fractions with good agreement with experimental results. Finally, a combined approach of experimental testing and molecular simulations is proposed to identify the parameters of the constitutive model. This study shows that the proposed simulation-based framework can be used to significantly reduce the number of experimental tests required for identification of material parameters without a significant loss of accuracy in the material response prediction. The predictive capability of the atomistically calibrated constitutive model is validated, with additional experimental results not used within the parameter identification, in terms of an accurate representation of the viscoelastic damage behaviour of nanoparticle/epoxy nanocomposites at finite temperatures. The present study underlines the capabilities of numerical molecular simulations intended for the characterisation of material properties with respect to physically based constitutive modelling and multi-scale approaches.

KW - Constitutive modelling

KW - Damage behaviour

KW - Nanocomposites

KW - Viscoelasticity

UR - http://www.scopus.com/inward/record.url?scp=85079208724&partnerID=8YFLogxK

U2 - 10.1016/j.polymer.2020.122265

DO - 10.1016/j.polymer.2020.122265

M3 - Article

AN - SCOPUS:85079208724

VL - 191

JO - POLYMER

JF - POLYMER

SN - 0032-3861

M1 - 122265

ER -