An integrative simulation concept for extrusion blow molded plastic bottles

Michels, Patrick; Grommes, Dirk; Oeckerath, André; Reith, Dirk; Bruch, Olaf

doi:10.1016/j.finel.2019.06.008

Cited by 10 publications

(10 citation statements)

References 2 publications

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“…Several properties of the final part such as the deformation behavior are predictable. Nevertheless, simulation results strongly depend on the input data for the analysis procedure [1][2][3][4][5]. Clearly the material description, consisting of the choice of the material model and the related material properties, influences the results.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Crystallization and Relaxation Effects in Coarse-Grained Polyethylene Systems after Uniaxial Stretching

et al. 2021

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In this study, we investigate the thermo-mechanical relaxation and crystallization behavior of polyethylene using mesoscale molecular dynamics simulations. Our models specifically mimic constraints that occur in real-life polymer processing: After strong uniaxial stretching of the melt, we quench and release the polymer chains at different loading conditions. These conditions allow for free or hindered shrinkage, respectively. We present the shrinkage and swelling behavior as well as the crystallization kinetics over up to 600 ns simulation time. We are able to precisely evaluate how the interplay of chain length, temperature, local entanglements and orientation of chain segments influences crystallization and relaxation behavior. From our models, we determine the temperature dependent crystallization rate of polyethylene, including crystallization onset temperature.

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Section: Introductionmentioning

confidence: 99%

Investigation of Crystallization and Relaxation Effects in Coarse-Grained Polyethylene Systems after Uniaxial Stretching

et al. 2021

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“…For the material modeling, the nonlinear viscoelastic K-BKZ model is used. Once the process simulation is finished, the self-developed interface is used to determine the local degrees of stretching and their orientations for each element of the process simulation mesh [12]. Together with the wall thickness distribution, the data is stored in the VMAP file and mapped to the meshes of the following analysis steps.…”

Section: Process Simulationmentioning

confidence: 99%

“…The main result is the wall thickness distribution that is used in all of the following analysis steps. Using a self‐developed interface, the local stretch ratios and their orientations are determined for each element of the process simulation mesh [12]. This information is necessary in order to define local orthotropic process‐dependent material behavior.…”

Section: Simulation Workflow Using the Vmap Interface Standardmentioning

confidence: 99%

Shrinkage simulation of blow molded parts using viscoelastic material models

Michels

Bruch

Evers-Dietze

et al. 2022

Materialwissenschaft Werkst

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The utilization of simulation procedures is gaining increasing attention in the product development of extrusion blow molded parts. However, some simulation steps, like the simulation of shrinkage and warpage, are still associated with uncertainties. The reason for this is on the one hand a lack of standardized interfaces for the transfer of simulation data between different simulation tools, and on the other hand the complex time‐, temperature‐ and process‐dependent material behavior of the used semi crystalline polymers. Using a new vendor neutral interface standard for the data transfer, the shrinkage analysis of a simple blow molded part is investigated and compared to experimental data. A linear viscoelastic material model in combination with an orthotropic process‐ and temperature‐dependent thermal expansion coefficient is used for the shrinkage prediction. A good agreement is observed. Finally, critical parameters in the simulation models that strongly influence the shrinkage analysis are identified by a sensitivity study.

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“…In this study, a novel extruder head for an annular expansion pipe was manufactured inspired by extrusion blow molding. [27] This type of extrusion head can continuously provide stretching and shearing actions to the polymer melt during continuous production. Thus, the molecular chains in the polymer melt can be rearranged to form an ordered structure and interlocking shishkebab network, thereby improving the mechanical properties of the pipes.…”

Section: Introductionmentioning

confidence: 99%

Effect of annular expansion pipe extruder head on mechanical properties of pipes

Pan

Wang

et al. 2021

Polymer Engineering & Sci

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With polymer pipes being used more commonly, performance requirements are increasing. Studies on the enhancement of mechanical properties of polymer pipes are particularly important. In this study, a self-designed annular expansion pipe extruder head was used to enhance the mechanical properties of HDPE pipes. Different morphologies of the HDPE pipes were produced under different processing conditions. When the extrusion angle was 30 (P30), the best mechanical properties were obtained. The hoop tensile strength and axial tensile strength were 14.5% and 41.0% higher, respectively, compared with the specimen without expansion (P0). This improvement of mechanical properties can be attributed to several reasons. First, the processing parameters of P30 reached the threshold shear rate and strain for shish-kebab formation, as shown by scanning electron microscopy. Second, P30 has the highest orientation parameter and crystallinity of 0.679 and 67.27%, respectively, from 2D wide-angle diffraction (WAXD). Polarized FTIR shows the same trend as 2D-WAXD. Third, the outer bamboo-like self-reinforced structure is formed inside the pipe at 30 expansion angle while the core layer has a well-formed crystal structure; the special structure improves the overall performance of HDPE pipe. This method can be utilized in large-scale industrial production.

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An integrative simulation concept for extrusion blow molded plastic bottles

Cited by 10 publications

References 2 publications

Investigation of Crystallization and Relaxation Effects in Coarse-Grained Polyethylene Systems after Uniaxial Stretching

Investigation of Crystallization and Relaxation Effects in Coarse-Grained Polyethylene Systems after Uniaxial Stretching

Shrinkage simulation of blow molded parts using viscoelastic material models

Effect of annular expansion pipe extruder head on mechanical properties of pipes

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