1. Home page
  2. Search

Some issues arising in finding the detachment point in calendering of plastic sheets

This item is provided by the institution :
National Technical University of Athens   

Repository :
Digital Library of National Technical University of Athens | Dspace@NTUA   

see the original item page
in the repository's web site and access all digital files if the item*



Some issues arising in finding the detachment point in calendering of plastic sheets (EN)
Mitsoulis, E (EN)
journalArticle (EN)
2014-03-01T01:34:37Z
2010 (EN)
Calendering is a process for producing plastic sheets of a desired final thickness and appearance. The thickness of the exiting sheet during a calendering operation is uniquely found by the lubrication approximation theory and the application of the Swift boundary conditions, which dictate that both the pressure and its axial derivative are zero at detachment. This cannot be used in a 2D analysis of the process, where the detachment point is the anchor of a free surface, and hence a singular point where both the pressure and the stresses go through numerical oscillations. This difficulty can be circumvented by using the boundary element method (BEM), which uses as primary variables velocities and tractions, and thus avoids pressures and stresses. Then the detachment point is found as the point where the tangential traction becomes zero. Numerical tests undertaken here with the finite element method (FEM) show that the LAT results can be used as a good approximation for the detachment point, which is then fixed. Comparisons with 2D BEM results show a good agreement for all flow field variables. However, the exact position of the detachment point in a 2D FEM analysis is still elusive, since for viscous polymer melts the contact angle is not known and should be part of the solution. Some thoughts are given about how to tackle this still unresolved issue, based on double nodes with discontinuous velocities and pressures. © The Author(s), 2010. (EN)
Materials Science, Coatings & Films (EN)
sheet thickness (EN)
free surfaces. (EN)
Finite Element (EN)
Plastic sheets (EN)
Surfaces (EN)
Traction (friction) (EN)
Calenders (EN)
Contact angle (EN)
Two dimensional (EN)
Crystallography (EN)
power-law model (EN)
Finite element method (EN)
Calendering (EN)
Polymer melts (EN)
Power law model (EN)
Sheet thickness (EN)
calendering (EN)
Approximation theory (EN)
finite elements (EN)
Boundary element method (EN)
Indexing (of information) (EN)
detachment point (EN)
Free surfaces (EN)
Journal of Plastic Film and Sheeting (EN)
English
SAGE PUBLICATIONS LTD (EN)
National Technical University of Athens
Digital Library of National Technical University of Athens | Dspace@NTUA
Κεντρική Βιβλιοθήκη Ε.Μ.Π.
Ιδρυματικό Αποθετήριο
Δημοσιεύσεις μελών Δ.Ε.Π. σε περιοδικά



*Institutions are responsible for keeping their URLs functional (digital file, item page in repository site)