Hot-drawing of poly(ethylene terephthalate) under biaxial stress: application of a three-dimensional glass—rubber constitutive model

Buckley, C. P.; Jones, Dominic; Jones, D.P.

doi:10.1016/0032-3861(96)85352-3

Cited by 123 publications

(98 citation statements)

References 23 publications

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“…Numerous researchers world-wide have developed their own test platforms and enabled significant advances to be made in understanding the evolution of microstructure in PET materials under processing conditions [3][4][5][6][7][8][9], and to generate stress strain data that is suitable for developing and validating constitutive material laws [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

A novel methodology to characterize the constitutive behaviour of polyethylene terephthalate for the stretch blow moulding process

Yan

Menary

Nixon

2017

Mechanics of Materials

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The stretch blow moulding (SBM) process is the main method for the mass production of PET containers. And understanding the constitutive behaviour of PET during this process is critical for designing the optimum product and process. However due to its nonlinear viscoelastic behaviour, the behaviour of PET is highly sensitive to its thermomechanical history making the task of modelling its constitutive behaviour complex. This means that the constitutive model will be useful only if it is known to be valid under the actual conditions of interest to the SBM process. The aim of this work was to develop a new material characterization method providing new data for the deformation behaviour of PET relevant to the SBM process. In order to achieve this goal, a reliable and robust characterization method was developed based on an instrumented stretch rod and a digital image correlation system to determine the stress-strain relationship of material in deforming preforms during free stretch-blow tests. The effect of preform temperature and air mass flow rate on the deformation behaviour of PET was also investigated.

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Section: Introductionmentioning

confidence: 99%

A novel methodology to characterize the constitutive behaviour of polyethylene terephthalate for the stretch blow moulding process

Yan

Menary

Nixon

2017

Mechanics of Materials

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“…Formula (6) coincides with the multiplicative presentation of the deformation gradient proposed in [41], where F e is called the ''network stretch'' tensor and F s is identified as the ''slippage stretch'' tensor. …”

Section: Kinematics Of Slidingmentioning

confidence: 97%

Finite viscoplasticity of semicrystalline polymers

Drozdov¹,

Christiansen

2003

Archive of Applied Mechanics (Ingenieur Archiv)

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A series of uniaxial tensile tests is performed on isotactic polypropylene at room temperature with cross-head speeds ranging from 5 to 100 mm/min. Prior to mechanical testing, injection-molded samples are annealed for 24 h at the temperature 160 C that ensures that the specimens can be drawn up to the Hencky strain of 0.6 without necking. A constitutive model is derived for the viscoplastic behavior of a semicrystalline polymer at finite strains. The stress-strain relations are determined by five adjustable parameters that are found by matching the observations. Fair agreement is demonstrated between the experimental data and the results of numerical simulation. It is shown that the material parameters in the constitutive equations are strongly affected by the strain rate. IntroductionThis paper is concerned with the effect of strain rate on the viscoplastic behavior of the injection-molded isotactic polypropylene (iPP) in isothermal uniaxial tensile tests at finite strains. The interest to the mechanical response of iPP is caused by its many industrial applications, ranged from oriented films for packaging to non-woven fabrics and reinforcing fibres. The influence of strain rate on the yield stress, defined as the point of maximum on the engineering stress-engineering strain curve, has been the focus of attention of some papers on polypropylene in the past decade, [1][2][3][4].The iPP is a semicrystalline polymer containing three basic crystallographic forms, [5]: monoclinic a-crystallites, (pseudo) hexagonal b-structures, orthorhombic c-polymorphs, and smectic mesophase, which consists of arrays of chains with a better order in the longitudinal than in transverse chain direction. At rapid cooling of the melt, which is typical of the injection-molding process, a-crystallites and smectic mesophase are mainly developed, whereas b-and c-polymorphs are observed as minor components, [6].The characteristic size of a-spherulites in an injection-molded specimen is estimated at 100-200 lm, [6, 7]. These structures are formed by lamellae stacks with lamellar thicknesses ranging from 10 to 20 nm, [7,8]. A unique feature of the crystalline morphology of iPP is the lamellar cross-hatching: development of transverse lamellae oriented in the direction perpendicular to the direction of radial lamellae in spherulites, [5,8].Transmission electron microscopy (TEM), [8,9], and polarized optical microscopy, [9], show that annealing of iPP at elevated temperatures results in

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“…The case for using this type of model has been verified by experimental blowing of a viscoelastic plastic into a bubble, cooling it, and upon reheating it, the bubble returned to its original flat shape. Ogden's model of elasticity is extensively 9 used in thermoforming to give relatively accurate thickness predictions, but it neglects the rate ef- PET, and various investigators such as 13 -15 Buckley have developed their own models to 16,17 simulate the PET deformation behavior. For this analysis, elasto-viscoplasticity was used to include rate sensitivity.…”

Section: Materials Modelmentioning

confidence: 99%

Simulation of the stretch blow molding process of PET bottles

McEvoy

Armstrong

Crawford

1998

Adv. Polym. Technol.

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Simulations of various stretch blow and blow moldings of axisymmetric PET bottles has been carried out using ABAQUS. A creep constitutive model with material data developed for a thermoforming process was used in the finite element analysis. Simulations using shell and solid elements were compared with experimental moldings. The creep material model, when combined with solid elements and a very high coefficient of friction, provided the best predictions for bottle side wall thickness, strains, blowing pressure, and general material movement. It was found that, using ABAQUS, the predicted wall thickness distribution of the material in an injection blow molded bottle agreed well with the values obtained using commercial process conditions. © 1998 John Wiley & Sons, Inc. Adv Polym Techn 17: 339–352, 1998

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Hot-drawing of poly(ethylene terephthalate) under biaxial stress: application of a three-dimensional glass—rubber constitutive model

Cited by 123 publications

References 23 publications

A novel methodology to characterize the constitutive behaviour of polyethylene terephthalate for the stretch blow moulding process

A novel methodology to characterize the constitutive behaviour of polyethylene terephthalate for the stretch blow moulding process

Finite viscoplasticity of semicrystalline polymers

Simulation of the stretch blow molding process of PET bottles

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