Rheology of Rubber–Clay Nanocomposites

Isayev, A. I.; Choi, Jaesun

doi:10.1002/9781118092866.ch8

Cited by 2 publications

(2 citation statements)

References 54 publications

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“…Isayev and Hieber first proposed a theoretical approach related to the nonlinear viscoelasticity for numerical simulation of injection moldings. Isayev carried out both theoretical and experimental investigations of squeezing flow of melt using nonlinear viscoelastic constitutive equations. Kim et al presented a viscoelastic flow model to investigate the birefringence of ICM part.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation for flow‐induced stress in injection/compression molding

Cao

Min

Zhang

et al. 2015

Polymer Engineering & Sci

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Flow‐induced stress in compression stage is complex because compression flow combines both shear flow and extensional flow characters and involves the boundary change in melt front and compressing directions. To describe this kind of flow effectively, the theoretical model was established in terms of three‐dimensional compressible and viscoelastic fluid, and the material derivative which includes mesh moving velocity was introduced to modify the convective terms in governing and constitutive equations based on Arbitrary Lagrangian Eulerian description. The corresponding variational equations were derived via Gauss formula and the finite element method was used to discretize the flow variables with mixed elements. In order to decouple the interdependence of velocity, stress, and temperature, a new approach involves twofold iterations was proposed to solve nonlinear flow problem. A new mesh updating scheme was presented to keep consistent with compressed regions. Numerical results indicate the compression can reduce the flow‐induced stress significantly compared to conventional injection molding, increase compressing velocity enlarges flow‐induced stress, and high temperature decreases flow‐induced stress. The proposed method was verified by photoelastic pictures and measured pressures and temperatures during molding. POLYM. ENG. SCI., 56:287–298, 2016. © 2015 Society of Plastics Engineers

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Section: Introductionmentioning

confidence: 99%

Numerical simulation for flow‐induced stress in injection/compression molding

Cao

Min

Zhang

et al. 2015

Polymer Engineering & Sci

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“…Isayev and Hieber [18] were the first who proposed a theoretical approach to relate the nonlinear viscoelasticity of polymers to the development of frozen‐in molecular orientation (birefringence) in CIM. Also, Isayev and Azari [19] and Isayev et al [20] carried out both theoretical and experimental investigations of squeezing flow of melt using a nonlinear viscoelastic constitutive equation. They considered the shear‐free flow and the channel flow with moving boundary squeezing the melt similar to that occurring in the compression stage of ICM.…”

Section: Introductionmentioning

confidence: 99%

Birefringence in injection‐compression molding of amorphous polymers: Simulation and experiment

Kim

Isayev

2013

Polymer Engineering & Sci

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The influence of the processing variables on the residual birefringence was analyzed for polystyrene and polycarbonate disks obtained by injection‐compression molding under various processing conditions. The processing variables studied were melt and mold temperatures, compression stroke, and switchover time. The modeling of flow‐induced residual stresses and birefringence of amorphous polymers in injection‐compression molded center‐gated disks was carried out using a numerical scheme based on a hybrid finite element/finite difference/control volume method. A nonlinear viscoelastic constitutive equation and stress‐optical rule were used to model frozen‐in flow stresses in moldings. The filling, compression, packing, and cooling stages were considered. Thermally‐induced residual birefringence was calculated using the linear viscoelastic and photoviscoelastic constitutive equations combined with the first‐order rate equation for volume relaxation and the master curves for the Young's relaxation modulus and strain‐optical coefficient functions. The residual birefringence in injection‐compression moldings was measured. The effects of various processing conditions on the measured and simulated birefringence distribution Δn and average transverse birefringence were elucidated. Comparison of the birefringence in disks manufactured by the injection molding and injection‐compression molding was made. The predicted and measured birefringence is found to be in fair agreement. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers

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Rheology of Rubber–Clay Nanocomposites

Cited by 2 publications

References 54 publications

Numerical simulation for flow‐induced stress in injection/compression molding

Numerical simulation for flow‐induced stress in injection/compression molding

Birefringence in injection‐compression molding of amorphous polymers: Simulation and experiment

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