Application of a large deformation model to unstable tensile stretching of polyethylene

Sweeney, J.; Collins, T. L. D.; Coates, Phil; Unwin, A. P.; Duckett, R. A.; Ward, I. M.

doi:10.1016/s0749-6419(00)00104-2

Cited by 24 publications

(13 citation statements)

References 24 publications

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“…This may not be appropriate to apply to Polypropylene in thermoforming situations. Other research to tackling such problems has focused on rheological [10] models of polymers which account for molecular chain dynamics and construction as well as elastic, plastic and viscous effects. The contact of the sheet with the tooling in plug-assisted thermoforming is a dominant influence on the thickness distribution of the formed component.…”

Section: Referencesmentioning

confidence: 99%

Finite element analysis of the thermoforming of Polypropylene

O'Connor¹,

Menary²,

Martin³

et al. 2008

Int J Mater Form

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Polypropylene (PP) is typically solid phase thermoformed at temperatures close to its crystalline melting point, usually in the 150° to 160° Celsius range. In such conditions the mechanical properties of the material rapidly decline with temperature and these large changes in properties make Polypropylene one of the more difficult materials to process by thermoforming. This paper presents the findings of a study into the thermoforming behaviour of an industrial thermoforming grade of Polypropylene. Practical tests were performed using custom built thermoforming equipment at Queen's University Belfast. Numerical simulations of these processes were similarly constructed to replicate thermoforming processes using industry standard Finite Element Analysis software.

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Section: Referencesmentioning

confidence: 99%

Finite element analysis of the thermoforming of Polypropylene

O'Connor¹,

Menary²,

Martin³

et al. 2008

Int J Mater Form

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“…This has been done both for polypropylene 21,24 and for polyethylene. 26 In all these cases, the constitutive equations have been based on an elastic network model, with no flow rule and therefore no potential for shear banding. Although this approach reflects the observed behavior, there seems to be no fundamen- tal physical reason for the inclusion of a flow rule for one class of polymer and its exclusion for another.…”

Section: Previous Work On Necksmentioning

confidence: 99%

Unified model of necking and shear banding in amorphous and semicrystalline polymers

Sweeney

Caton‐Rose

Spares

et al. 2007

J of Applied Polymer Sci

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“…The force-extension data was regressed using industry standard spreadsheet software to provide plots of stress versus strain for the samples that were tested. [2,3,4,5,6,7,8,9,10] model. This model will now be discussed as it is one of the major themes of this document.…”

Section: Biaxial Testingmentioning

confidence: 99%

“…The models were constructed using the Finite Element Analysis software ABAQUS [11] . The material model chosen was that proposed by Sweeney et al [2,3,4,5,6,7,8,9,10] . Using this theory a 'user subroutine' was developed at QUB describing the behaviour of the Sweeney model such that it could be used in conjunction with ABAQUS to facilitate the research.…”

Section: The Sweeney Modelmentioning

confidence: 99%

Viscoelastic Material Models of Polypropylene for Thermoforming Applications

O'Connor¹,

Martin²,

Menary³

2010

Int J Mater Form

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Polypropylene (PP), a semi-crystalline material, is typically solid phase thermoformed at temperatures associated with crystalline melting, generally in the 150° to 160° Celsius range. In this very narrow thermoforming window the mechanical properties of the material rapidly decline with increasing temperature and these large changes in properties make Polypropylene one of the more difficult materials to process by thermoforming. Measurement of the deformation behaviour of a material under processing conditions is particularly important for accurate numerical modelling of thermoforming processes. This paper presents the findings of a study into the physical behaviour of industrial thermoforming grades of Polypropylene. Practical tests were performed using custom built materials testing machines and thermoforming equipment at Queen's University Belfast. Numerical simulations of these processes were constructed to replicate thermoforming conditions using industry standard Finite Element Analysis software, namely ABAQUS and custom built user material model subroutines. Several variant constitutive models were used to represent the behaviour of the Polypropylene materials during processing. This included a range of phenomenological, rheological and blended constitutive models. The paper discusses approaches to modelling industrial plug-assisted thermoforming operations using Finite Element Analysis techniques and the range of material models constructed and investigated. It directly compares practical results to numerical predictions. The paper culminates discussing the learning points from using Finite Element Methods to simulate the plug-assisted thermoforming of Polypropylene, which presents complex contact, thermal, friction and material modelling challenges.The paper makes recommendations as to the relative importance of these inputs in general terms with regard to correlating to experimentally gathered data. The paper also presents recommendations as to the approaches to be taken to secure simulation predictions of improved accuracy.

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Application of a large deformation model to unstable tensile stretching of polyethylene

Cited by 24 publications

References 24 publications

Finite element analysis of the thermoforming of Polypropylene

Finite element analysis of the thermoforming of Polypropylene

Unified model of necking and shear banding in amorphous and semicrystalline polymers

Viscoelastic Material Models of Polypropylene for Thermoforming Applications

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