Viscoelastic Modelling of Entrance Flow Using Multimode Leonov Model

Gupta, Mahesh; Hieber, C. A.; Wang, K. K.

doi:10.1002/(sici)1097-0363(19970315)24:5<493::aid-fld502>3.0.co;2-w

Cited by 16 publications

(7 citation statements)

References 32 publications

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“…The Leonov CE and its variations have been successfully employed to model different types of flows including oscillatory shear, stress relaxation, steady shear, uniaxial extension, biaxial extension, startup shear, entrance flow, planar flow, and squeezing flow for both unfilled 75,80,81,114,132,133–157 and particle‐filled systems 89–93,95,98,114,132,133,153,158–161 . It has even been successfully employed to model the complex flow behavior encountered in injection molding for unfilled polymers 162,163 …”

Section: Simulating Rheological Behavior Using the Simhambhatla‐leonomentioning

confidence: 99%

Correlations in rheological behavior between large amplitude oscillatory shear and steady shear flow of silica‐filled star‐shaped styrene‐butadiene rubber compounds: Experiment and simulation

Pole

Isayev

2021

J of Applied Polymer Sci

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The large amplitude oscillatory shear (LAOS) and steady shear behavior of star‐shaped SSBR/silica 60 phr (21 vol%) compounds with various filler surface areas was measured and simulated. An SBR gum and SBR compounds containing four different silicas with surface areas of 55, 135, 160, and 195 m2/g were utilized. Rheological behavior indicated clear correlation with surface area. LAOS tests showed an increase in dynamic moduli, shear stress, and higher order harmonic contributions with surface area. Elastic and viscous Lissajous figures showed significant distortion at intermediate and higher strain amplitudes. Additionally, ratios of third and fifth order stress harmonics to the first stress harmonic (I3/1 and I5/1, respectively) showed a ''bump'' at intermediate strain amplitudes for the three highest surface area compounds. With regards to steady shear, all materials showed strong shear thinning behavior, and an increase in shear viscosity with surface area. The Cox‐Merz rule was shown to be valid for the SBR gum but not for the filled compounds. However, the complex viscosity as a function of shear rate amplitude at various frequencies at high strain amplitudes and the steady shear viscosity as a function of shear rate coincided. This correlation, referred to as the Philippoff approach, has important ramifications for the rubber industry, providing quick data for predicting processing behavior. The Simhambhatla‐Leonov model was successfully employed to simulate rheological behavior for the SBR gum and the lowest surface area silica compound, but the model yielded mixed results for the higher surface area silica compounds.

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Section: Simulating Rheological Behavior Using the Simhambhatla‐leonomentioning

confidence: 99%

Correlations in rheological behavior between large amplitude oscillatory shear and steady shear flow of silica‐filled star‐shaped styrene‐butadiene rubber compounds: Experiment and simulation

Pole

Isayev

2021

J of Applied Polymer Sci

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“…However, poor prediction still exists in the runner and gate systems where polymers accumulate significant recoverable strain because of their viscoelastic nature [96]. This implies that for processes with apparent extensional flow (e.g., polymer melt in μIM), predictions with viscous rheological models can be quite different from the real flow [97]. Therefore, in order to include elastic effects, the viscoelastic models need to be utilized in simulation.…”

Section: Elastic Effectsmentioning

confidence: 99%

Microinjection molding of microsystem components: new aspects in improving performance

Yang

Yin

Cheng

2013

J. Micromech. Microeng.

101

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Microinjection molding (μIM) is considered to be one of the most flexible, reliable and cost effective manufacturing routes to form plastic micro-components for microsystems. The molding machine, mold tool fabrication, material selection and process controlling in this specific field have been greatly developed over the past decades. This review aims to present the new trends towards improving micro-component performance by reviewing the latest developments in this area and by considering potential directions. The key concerns in product and mold designing, essential factors in simulation, and micro-morphology and resultant properties are evaluated and discussed. In addition, the applications, variant processes and outlook for μIM are presented. Throughout this review, decisive considerations in seeking improved performance for microsystem components are highlighted.

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“…These viscous model based works have been successfully used in many applications involving shear-dominated flows such as in the injection and compression molding of polymers. However, in applications involving elongational flow, predictions from such a simple formulation can be quite different from the real flow [12]. Owing to their viscoelastic nature, polymers accumulate significant recoverable strain.…”

Section: Introductionmentioning

confidence: 99%

Model and simulation for melt flow in micro-injection molding based on the PTT model

Cao

Kong

et al. 2011

Modelling Simul. Mater. Sci. Eng.

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Unsteady viscoelastic flows were studied using the finite element method in this work. The Phan-Thien–Tanner (PTT) model was used to represent the rheological behavior of viscoelastic fluids. To effectively describe the microscale effects, the slip boundary condition and surface tension were added to the mathematical model for melt flow in micro-injection molding. The new variational equation of pressure, including the viscoelastic parameters and slip boundary condition, was generalized using integration by parts. A computer code based on the finite element method and finite difference method was developed to solve the melt flow problem. Numerical simulation revealed that the melt viscoelasticity plays an important role in the prediction of melt pressure, temperature at the gate and the succeeding melt front advancement in the cavity. Using the viscoelastic model one can also control the rapid increase in simulated pressure, temperature, and reduce the filling difference among different cavities. The short shot experiments of micro-motor shaft showed that the predicted melt front from the viscoelastic model is in fair agreement with the corresponding experimental results.

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Viscoelastic Modelling of Entrance Flow Using Multimode Leonov Model

Cited by 16 publications

References 32 publications

Correlations in rheological behavior between large amplitude oscillatory shear and steady shear flow of silica‐filled star‐shaped styrene‐butadiene rubber compounds: Experiment and simulation

Correlations in rheological behavior between large amplitude oscillatory shear and steady shear flow of silica‐filled star‐shaped styrene‐butadiene rubber compounds: Experiment and simulation

Microinjection molding of microsystem components: new aspects in improving performance

Model and simulation for melt flow in micro-injection molding based on the PTT model

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