Extrudate swell of a high-density polyethylene melt: II. Modeling using integral and differential constitutive equations

Konaganti, Vinod Kumar; Ansari, Mahmoud; Mitsoulis, Evan; Hatzikiriakos, Savvas G.

doi:10.1016/j.jnnfm.2015.07.005

Cited by 47 publications

(53 citation statements)

References 56 publications

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“…The die-swell coefficient is plotted in Fig. 5, and compared with experimental measurements and simulation results with the K-BKZ model in Konaganti et al [2015]. It shows that the results of the current solver for Mat A is quite similar to the experimental results, and only slight difference with the simulation results of the K-BKZ model, which shows that the current model works very well for die-swell effect simulations.…”

Section: Free Surface Flow and Die-swell Effectmentioning

confidence: 67%

“…For testing the capabilities of multi-phase flow with free surface, an axi-symmetric computational model for simulating die-swell effect was established according to Konaganti et al [2015], and the geometry and related mesh profile are illustrated in Fig. 4.…”

Section: Free Surface Flow and Die-swell Effectmentioning

confidence: 99%

“…To determine the material parameters, we choose the 6-mode Giesekus viscoelastic constitutive law with parameters measured in Konaganti et al [2015], and listed in Table 3. These parameters are directly calibrated from experimental data on HDPE, since they represent real material behavior.…”

Section: Free Surface Flow and Die-swell Effectmentioning

confidence: 99%

See 2 more Smart Citations

Direct Simulation of Polymer Fused Deposition Modeling (FDM) — An Implementation of the Multi-Phase Viscoelastic Solver in OpenFOAM

Liu

Anderson²,

Sridhar

2019

Int. J. Comput. Methods

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Among the many mature and commercial AM technologies, fused deposition modeling (FDM) is a popular technology commonly used for modeling, prototyping, and production applications. In this process, a filament thermoplastic material is fed into a liquefier chamber, melted to a liquid state, and deposited layer by layer through a nozzle to form the 3D part. As a result, part can be designed in a more freedom way, and fabricated quickly and rapidly to a desired shape. However, different combination of processing parameters may influence the final part quality greatly, which hinders wider application of this technique. In order to investigate the influence of processing parameters on the final part quality, a viscoelastic multi-phase solver is developed, with capability for dynamic meshing and based on OpenFOAM. The solver directly simulates the deposition process of FDM. By implementing this solver for different boundary conditions and geometry, we can evaluate the printed part quality for varied processing conditions. More importantly, the tool enables efficient optimization of the processing conditions for specified material parameters and desired print quality.

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Section: Free Surface Flow and Die-swell Effectmentioning

confidence: 67%

Section: Free Surface Flow and Die-swell Effectmentioning

confidence: 99%

See 1 more Smart Citation

Direct Simulation of Polymer Fused Deposition Modeling (FDM) — An Implementation of the Multi-Phase Viscoelastic Solver in OpenFOAM

Liu

Anderson²,

Sridhar

2019

Int. J. Comput. Methods

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“…It is therefore necessary to use a fluid dynamics package capable of computing viscoelastic flows. This has been attempted in the context of extrudate swell using the K-BKZ [9], Phan-Thien Tanner (PTT) [10], Oldroyd-B [11] and the Pom-Pom [12] models amongst others. In 2011 Ganvir et al [12] used a Lagrangrian-Eulerian method and the XPP (eXtended Pom-Pom) [13] model.…”

Section: Introductionmentioning

confidence: 99%

Theoretical prediction and experimental measurement of isothermal extrudate swell of monodisperse and bidisperse polystyrenes

Robertson

Thompson

McLeish

et al. 2017

Journal of Rheology

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Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractThis paper describes the theoretical prediction, finite element simulation and experimental studies of extrudate swell in monodisperse and bidisperse polystyrenes. We present a molecular approach to understanding extrudate swell using the tube-model-based Rolie-Poly constitutive equation within a Lagrangian finite element solver. This yields theoretical predictions of swelling which show a close universality: the molecular weight dependence of the swelling can be removed when the flow speed is scaled by the Rouse Weissenberg number. The roles that both chain orientation and stretch play in determining extrudate swell are clearly identifiable from plots of swelling ratio against each Weissenberg number. We also present isothermal extrusion experiments on the same polymers and can obtain good predictions well into the strong chain stretching regime. The predictions for swelling ratios match those from experiments up to Rouse Weissenberg numbers of ~7, above which swelling is over-predicted by the Rolie-Poly equation.

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“…They showed that extrudate swell changed nonlinearly with entrance angle, and that the molecular structure a ected the extrudate swell signi cantly. Konaganti et al [19] numerically studied the extrudate swell phenomenon using di erent viscoelastic constitutive equations. They found that integral models highly overpredicted the extrudate swell, whereas di erential models slightly underpredicted the phenomenon.…”

Section: Introductionmentioning

confidence: 99%

Study on the Viscoelastic Fluid Behavior in Hollow Fiber Membrane Fabrication Process Using Giesekus’ Model

2017

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Abstract. In the present study, attempts are made to study the behavior of a viscoelastic uid in the hollow ber membrane production process. For this purpose, the uid is considered to obey the Giesekus' model and ow is taken as steady, two-dimensional and isothermal one. The ow eld is obtained using DEVSS/SUPG scheme combined with a free surface tracking method. The obtained results are compared to the case of Newtonian uid. It is shown that the extrudate swell is 20% more in the case of viscoelastic uid. Moreover, the elastic behavior of the viscoelastic uid signi cantly a ects the velocity eld in the extrudate outside the die. It causes the uid ow to become reversed in the middle part of the extrudate as the direct result of the stress relaxation process, whereas such a behavior is not seen for Newtonian uid. Also, the First Normal Stress Di erence (FNSD) distribution in the extrudate is obtained and its variation is discussed. Furthermore, the e ects of operational parameters, including die back pressure and take-up velocity, are investigated. Finally, the predicted extrudate swell for various operation conditions is compared to experimental results showing good agreement between experimental and simulated data.

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Extrudate swell of a high-density polyethylene melt: II. Modeling using integral and differential constitutive equations

Cited by 47 publications

References 56 publications

Direct Simulation of Polymer Fused Deposition Modeling (FDM) — An Implementation of the Multi-Phase Viscoelastic Solver in OpenFOAM

Direct Simulation of Polymer Fused Deposition Modeling (FDM) — An Implementation of the Multi-Phase Viscoelastic Solver in OpenFOAM

Theoretical prediction and experimental measurement of isothermal extrudate swell of monodisperse and bidisperse polystyrenes

Study on the Viscoelastic Fluid Behavior in Hollow Fiber Membrane Fabrication Process Using Giesekus’ Model

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