TY  - JOUR
AB  - Purpose The purpose of this study is to present a finite element (FE) implementation of phenomenological three-dimensional viscoelastic and viscoplastic constitutive models for long term behaviour prediction of polymers.Design/methodology/approach The method is based on the small strain assumption but is extended to large deformation for materials in which the stress-strain relation is nonlinear and the concept of incompressibility is governing. An empirical approach is used for determining material parameters in the constitutive equations, based on measured material properties. The modelling process uses a spring and dash-pot and a power-law approximation function method for viscoelastic and viscoplastic nonlinear behaviour, respectively. The model improvement for long term behaviour prediction is done by modifying the material parameters in such a way that they account for the current test time. The determination of material properties is based on the non-separable type of relations for nonlinear materials in which the material properties change with stress coupled with time.Findings The proposed viscoelastic and viscoplastic models are implemented in a user material algorithm of the FE general-purpose program ABAQUS and the validity of the models is assessed by comparisons with experimental observations from tests on high-density polyethylene samples in one-dimensional tensile loading. Comparisons show that the proposed constitutive model can satisfactorily represent the time-dependent mechanical behaviour of polymers even for long term predictions.Originality/value The study provides a new approach in long term investigation of material behaviour using FE analysis.
VL  - 37
IS  - 8
SN  - 0264-4401
DO  - 10.1108/EC-02-2019-0062
UR  - https://doi.org/10.1108/EC-02-2019-0062
AU  - Sepiani Hossein
AU  - Polak Maria Anna
AU  - Penlidis Alexander
PY  - 2020
Y1  - 2020/01/01
TI  - Finite element implementation of viscoelastic and viscoplastic models
T2  - Engineering Computations
PB  - Emerald Publishing Limited
SP  - 2561
EP  - 2585
Y2  - 2024/09/19
ER  -