Film blowing process is a flexible mass production technology used for manufacturing
thin polymeric films. Its flexibility in using an existing die to produce films
of different width and thickness, just by controlling process conditions such as, extrudate
velocity, excess pressure, and line speed, makes it an attractive process with
less capital investment. Controlling the process conditions to obtain a stable bubble,
however, is not a trivial task. It is a costly trial and error procedure, which could
result is a large wastage of material and other resources. Hence, it is necessary to
develop methods to simulate the process and design it using numerical experiments.
This important need of the industry defines the objective of this work. In this dissertation,
a transient, axisymmetric, nonisothermal, viscoelastic model is developed
to simulate the process, and it is solved using finite element method. Material behavior
of polymer melt is described using a modified Phan-Thien-Tanner model in
the liquid??like region, and anisotropic Kelvin??Voight model in the solid zone, and
the transition is modeled using a simple mixture theory. Crystallization kinetics is
described using a modified Avrami model with factors to account for the influence
of temperature and strain. Results obtained are compared with available experimental
results and the model is used to explore stability issues and the role of different
parameters. Software developed using this model comes with a GUI based pre- and
post-processor, and it can be easily adapted to use other constitutive models.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/2454 |
| Date | 29 August 2005 |
| Creators | Mayavaram, Ravisankar S. |
| Contributors | Reddy, Junuthula N. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 1079896 bytes, electronic, application/pdf, born digital |
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