TY - JOUR

T1 - A viscoelastic damage model for nanoparticle/epoxy nanocomposites at finite strain

T2 - A multiscale approach

AU - Arash, Behrouz

AU - Exner, Wibke

AU - Rolfes, Raimund

N1 - Funding information: This work originates from the research project ‘Hybrid laminates and nanoparticle reinforced materials for improved rotor blade structures’ (‘LENAH - Lebensdauererhöhung und Leichtbauoptimierung durch nanomodifizierte und hybride Werkstoffsysteme im Rotorblatt’), funded by the Federal Ministry of Education and Research of Germany Funding number is 03SF0529. The authors wish to express their gratitude for the financial support. This work originates from the research project ‘Hybrid laminates and nanoparticle reinforced materials for improved rotor blade structures’ (‘LENAH - Lebensdauererhöhung und Leichtbauoptimierung durch nanomodifizierte und hybride Werkstoffsysteme im Rotorblatt’), funded by the Federal Ministry of Education and Research of Germany Funding number is 03SF0529 . The authors wish to express their gratitude for the financial support.

PY - 2019/7

Y1 - 2019/7

N2 - Experimental tests show that nonlinear viscoelasticity characterizes the mechanical behavior of boehmite nanoparticle (BNP)/epoxy nanocomposites. This paper presents the development and numerical implementation of a physically based constitutive model for BNP/epoxy nanocomposites undergoing finite strain. The proposed constitutive model allows capturing the main features of the stress-strain relationship of BNP/epoxy nanocomposites, including the nonlinear hyperelastic, time-dependent and softening behavior. The characterizing feature of this study is to propose a methodological framework based on molecular dynamics simulations and experimental tests to identify the material parameters for the model. Molecular simulations in conjunction with the Eyring viscosity theory are used to characterize the viscoelastic deformation of epoxy resins under loading. The concept of strain amplification is also adopted to account for the effect of nanoparticles on the stress–strain response of the nanocomposites. The stress softening behavior is captured by a monotonically increasing function of deformation, so-called damage variable. The results show that the model predictions of stress-strain relationships are in good agreement with experimental data at different BNP weight fractions. Finally, the constitutive model is implemented in the finite element analysis and examined by means of a benchmark example. Experimental–numerical validation confirms the predictive capability of the present modeling framework, which provides a suitable tool for analyzing BNP/epoxy nanocomposites.

AB - Experimental tests show that nonlinear viscoelasticity characterizes the mechanical behavior of boehmite nanoparticle (BNP)/epoxy nanocomposites. This paper presents the development and numerical implementation of a physically based constitutive model for BNP/epoxy nanocomposites undergoing finite strain. The proposed constitutive model allows capturing the main features of the stress-strain relationship of BNP/epoxy nanocomposites, including the nonlinear hyperelastic, time-dependent and softening behavior. The characterizing feature of this study is to propose a methodological framework based on molecular dynamics simulations and experimental tests to identify the material parameters for the model. Molecular simulations in conjunction with the Eyring viscosity theory are used to characterize the viscoelastic deformation of epoxy resins under loading. The concept of strain amplification is also adopted to account for the effect of nanoparticles on the stress–strain response of the nanocomposites. The stress softening behavior is captured by a monotonically increasing function of deformation, so-called damage variable. The results show that the model predictions of stress-strain relationships are in good agreement with experimental data at different BNP weight fractions. Finally, the constitutive model is implemented in the finite element analysis and examined by means of a benchmark example. Experimental–numerical validation confirms the predictive capability of the present modeling framework, which provides a suitable tool for analyzing BNP/epoxy nanocomposites.

KW - Boehmite nanoparticle

KW - Epoxy resin

KW - Finite element analysis

KW - Molecular dynamics simulations

KW - Viscoelastic damage model

UR - http://www.scopus.com/inward/record.url?scp=85064323654&partnerID=8YFLogxK

U2 - 10.1016/j.jmps.2019.04.004

DO - 10.1016/j.jmps.2019.04.004

M3 - Article

AN - SCOPUS:85064323654

VL - 128

SP - 162

EP - 180

JO - Journal of the Mechanics and Physics of Solids

JF - Journal of the Mechanics and Physics of Solids

SN - 0022-5096

ER -