The Effect of Temperature, Strain Rate and Strain on the Induced Mechanical Properties of Biaxially Stretched PET

Menary, Gary; Tan, C.W.; Armstrong, Cecil

doi:10.4028/www.scientific.net/kem.504-506.1117

Cited by 14 publications

(13 citation statements)

References 9 publications

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“…The lower stress response was from the test with the higher heating temperature. However the gradient of the strain hardening region is less diverse when compared with the data typically generated from biaxial stretching tests [9][11], even when comparing a similar temperature range from 91℃ to 105℃. The cause of this observation is due to the deformation of the material being driven by the internal pressure during the blowing instead of being controlled by the imposed displacement profile in the biaxial stretching test, i.e.…”

Section: Figure 11 (B) and (D)mentioning

confidence: 99%

“…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%

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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: Figure 11 (B) and (D)mentioning

confidence: 99%

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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“…Each part of the constitutive model was represented by complex equations that required a large amount of data to perform accurate curve fitting procedures. The material data used for the curve fitting procedure, and as a result the material constants, were determined from extensive material testing using the QUB biaxial stretcher [19,20] and strain history form the DIC analysis of the FSB trials. The biaxial testing was performed on 76x76x0.5mm samples of PET cut from extruded sheet, the same grade as the preform material.…”

Section: Free-blow Simulation Set-upmentioning

confidence: 99%

“…The material characterisation technique using the biaxial stretching machine was not able to replicate the sequential deformation type for every foreseeable stretch scenario; indeed, only constant width and pure biaxial deformation were captured. The amount of initial linear stretch, and therefore the onset of orientation and eventual strain hardening [19][20][21][22][23][24][25][26][27][28][29], significantly affects the inflation of the preform.…”

Section: Free-blow Analysismentioning

confidence: 99%

Measuring and modelling air mass flow rate in the injection stretch blow moulding process

Salomeia¹,

Menary

Armstrong

et al. 2015

Int J Mater Form

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The injection stretch blow moulding process involves the inflation and stretching of a hot preform into a mould to form bottles. A critical process variable and an essential input for process simulations is the rate of pressure increase within the preform during forming, which is regulated by an air flow restrictor valve. The paper describes a set of experiments for measuring the air flow rate within an industrial ISBM machine and the subsequent modelling of it with the FEA package AbaqusABAQUS. Two rigid containers were inserted into a Sidel SBO1 blow moulding machine and subjected to different supply pressures and air flow restrictor settings. The pressure and air temperature were recorded for each experiment enabling the mass flow rate of air to be determined along with an important machine characteristic known as the 'dead volume'. The experimental setup was simulated within the commercial FEA package AbaqusABAQUS/Explicit using a combination of structural, fluid and fluid link elements that idealize the air flowing through an orifice behaving as an ideal gas under isothermal conditions. Results between experiment and simulation are compared and show a good correlation.

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“…The experimental results available in Lebaudy et al (1995), Schmidt et al (2003) and Monteix et al (2001) were also used to validate numerical simulations. Recently, Salomeia et al (2013) and Menary (2012) did the first temperature measurements of the air blown inside the bottle. They showed that the temperature of the air increases as soon as the preform is introduced in the mold, before the beginning of the preblow.…”

Section: Introductionmentioning

confidence: 99%

Simplified Modeling of Convection and Radiation Heat Transfer during Infrared Heating of PET Sheets and Preforms

Luo

Chevalier

Utheza

et al. 2015

International Polymer Processing

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of the convection and radiation heat transfers during the infrared heating of PET sheets and preforms Nomenclature. AbstractInitial heating conditions and temperature effects have important influence during the ISBM process of PET preforms. The numerical simulation of infrared (IR) heating taking into account the air convection is very time-consuming even for 2D modelling. This work proposes a simplified approach of the coupled heat transfers in the ISBM process based on the results of a complete air convection and IR heating simulation of PET sheet using ANSYS/Fluent. First, the simplified approach is validated by comparing the experimental temperature distribution of a PET sheet obtained from an IR camera with the numerical results of the simulation. Second, we focus on the PET preform heated by IR lamps. This problem cannot be modelled in 2D and the complete 3D approach is out of calculation possibilities actually. In our approach, the IR heating flux coming from IR lamps is calculated using radiative laws adapted to the test geometry. Finally, the simplified approach used on the 2D plane sheet case to model the air convection is applied to the heat transfer between the preform and ambient air using a simpler model in Comsol where only the preform is meshed.The temperature distribution on the outer surface of the preform is compared to the thermal imaging for validation.

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The Effect of Temperature, Strain Rate and Strain on the Induced Mechanical Properties of Biaxially Stretched PET

Cited by 14 publications

References 9 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

Measuring and modelling air mass flow rate in the injection stretch blow moulding process

Simplified Modeling of Convection and Radiation Heat Transfer during Infrared Heating of PET Sheets and Preforms

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