Two-process constitutive model for semicrystalline polymers across a wide range of strain rates
Autor: | Michael Okereke, Ambrose I. Akpoyomare |
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Jazyk: | angličtina |
Rok vydání: | 2019 |
Předmět: |
chemistry.chemical_classification
Polymers and Plastics Organic Chemistry Constitutive equation 02 engineering and technology Polymer 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Viscoelasticity 0104 chemical sciences Amorphous solid Condensed Matter::Soft Condensed Matter Condensed Matter::Materials Science chemistry TA Materials Chemistry Relaxation (physics) Deformation (engineering) Composite material 0210 nano-technology Adiabatic process Glass transition |
ISSN: | 0032-3861 |
Popis: | The presence of crystalline and amorphous phases in semicrystalline polymers presents interesting constitutive modelling challenges. In this study, a physically based, three-dimensional constitutive model has been developed for simulating a wide range of features observed in deformation and processing of semicrystalline polymers. The proposed model combines into one constitutive model such features as: multiple viscoelastic relaxation processes, very wide strain-rate range, temperature-dependence, adiabatic heating, structural rejuvenation; in addition to it being applied to a semicrystalline polymer. The constitutive mathematics is based on a one-process glass-rubber model for amorphous polymers. It adapts that model to semicrystalline polymers by extending it to two relaxation processes: one associated with the glass transition of the mobile amorphous phase; the other associated with relaxation of the crystalline fraction and its associated rigid amorphous phase. In particular, two dominant processes were identified: the α-process and the β-process. The model has been implemented numerically into a commercial finite element code through a user-defined material subroutine (UMAT). The model has been validated against compression test results carried out on polypropylene. Also, the model predicts very well the experimentally observed nonlinear rate-dependent response and post-yield de-ageing of polypropylene. |
Databáze: | OpenAIRE |
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