Computational Polymer Processing

Mitsoulis, Evan

doi:10.1002/9783527630257.ch4

Cited by 11 publications

(8 citation statements)

References 138 publications

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“…Polymer melts are only compressible under very high pressures [69]. Therefore, polymer melts are usually assumed to be incompressible, thus, the time derivative of the density is set to zero in (1.2).…”

Section: Conservation Equationsmentioning

confidence: 99%

Modeling and simulation for varying die gap fluid extrusion

Toukhtarian

2019

Preprint

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The analysis and the simulation of fluid extruded out of a die opening are of great importance in different industrial applications. Mathematical modeling and experimental studies of extrusion out of a constant die gap has been the subject of numerous publications in the literature. Extrusion Blow Molding is a polymer forming technique used to manufacture a wide range of large hollow parts such as fuel tanks used in the automotive industry. The die gap is varied during extrusion to adjust the manufactured product's final thickness and to compensate for uneven stretching during molding. In this work, mathematical modeling of varying die gap extrusion is introduced. Two models using different approaches are presented to model the time dependent effects of varying the die gap on the extrudate.In the first approach, physics based partial differential equations are used to simulate extrusion. The Navier Stokes equations are used as governing equations to simulate molten polymers. The governing equations are solved using Arbitrary Lagrangian Eulerian based Finite Element Method. A novel numerical method for defining the free surface of the extrudate is proposed. In addition, the effects of varying the die gap on the material velocity, pressure and extrudate shape are reported.In the second approach, a parameter identification scheme is used to obtain the parameters of a novel model with a predefined structure. The purpose of the proposed model is to replicate time dependent extrudate thickness of the physics based model. The parameters of the model are identified by minimizing the response error between the two models due to step inputs. The parameter identification based model provides a computationally low cost alternative to the physics based model. Moreover, the parameter identification based model has a transport Partial Differential Equation/Ordinary Differential Equation cascade structure that is suitable for designing feedback controllers for Extrusion Blow Molding.First, I would like to express sincere gratitude and appreciation to my supervisor Prof. Benoit Boulet for his great guidance and the intellectual freedom I was granted throughout this research. This work would not have been possible without his great dedication, constructive criticism and support. A special thanks to my co-supervisor Prof. Roni Khazaka for his mentorship and guidance. I also gratefully acknowledge Prof. Savvas Hatzikiriakos and Mr. Haile Atsbha for sharing with me their profound knowledge and expertise. I gratefully acknowledge the Natural Sciences and Engineering Research Council of Canada (Automotive Partnership Canada) for the financial support and giving me the opportunity to pursue my passion in science and engineering.Finally, I would like to thank my loving friends and family for their encouragement and support along my journey over the past five years. viii

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Section: Conservation Equationsmentioning

confidence: 99%

Modeling and simulation for varying die gap fluid extrusion

Toukhtarian

2019

Preprint

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“…We consider the conservation equations of mass, momentum and energy for incompressible fluids under non-isothermal, creeping, steady flow conditions. These are written as [14,15]…”

Section: Governing Equationsmentioning

confidence: 99%

“…The viscous stresses are given for inelastic non-Newtonian incompressible fluids by the relation [14,15]:…”

Section: Governing Equationsmentioning

confidence: 99%

Flow behaviour of rubber in capillary and injection moulding dies

Mitsoulis

Battisti

Neunhäuserer

et al. 2017

Plastics, Rubber and Composites

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This study is concerned with the flow behaviour of a rubber compound in capillary and injection moulding dies in the temperature range of 80-120°C. The injection moulding die designs had a tapered angle ranging from 40°up to 150°. The rheological characterisation of the rubber compound in the capillary dies showed that rubber slips at the wall, and this was modelled with an appropriate slip law. The pressure drops in the system were measured for all tapered dies. Numerical simulations were then carried out with a purely viscous (Carreau) model and a multimode viscoelastic (K-BKZ) model. The results showed a good agreement with the experiments for both the capillary and the injection moulding dies, provided that slip is included in the simulations as determined experimentally.

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“…Most of the computational time is used for the solution of the --problem, while the a posteriori computation of the stresses takes approximately an equal amount of CPU time (at least this is the case for the middle range of flow rates; at low flow rates the Newtonianlike behavior of polymer melts makes the computation of stresses extremely fast; at the other end of very high flow rates, the computation of stresses becomes most time consuming). Thus, it was possible to solve many 2-D flow problems by the year 2000 in the personal computers (PCs) of the day, as evidenced in a series of papers by Mitsoulis and his coworkers [91].…”

Section: Some Issues Arising In Viscoelasticmentioning

confidence: 99%

“…(5) Many works focused on simulating real data and phenomena associated with polymer melt flows in rheology and polymer processing, in most cases with considerable success [91].…”

Section: Conclusion and Future Prospectsmentioning

confidence: 99%

50 Years of the K-BKZ Constitutive Relation for Polymers

Mitsoulis

2013

ISRN Polymer Science

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The K-BKZ constitutive model is now 50 years old. The paper reviews the connections of the model and its variants with continuum mechanics and experiment, presenting an up-to-date recap of research and major findings in the open literature. In the Introduction a historical perspective is given on developments in the last 50 years of the K-BKZ model. Then a section follows on mathematical modeling of polymer flows, including governing equations of flow, rheological constitutive equations (with emphasis on viscoelastic integral constitutive equations of the K-BKZ type), dimensionless numbers, and boundary conditions. The Method of Solution section reviews the major developments of techniques necessary for particle tracking and calculation of the integrals for the viscoelastic stresses in flow problems. Finally, selected examples are given of successful application of the K-BKZ model in polymer flows relevant to rheology.

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Computational Polymer Processing

Cited by 11 publications

References 138 publications

Modeling and simulation for varying die gap fluid extrusion

Modeling and simulation for varying die gap fluid extrusion

Flow behaviour of rubber in capillary and injection moulding dies

50 Years of the K-BKZ Constitutive Relation for Polymers

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