51173
Accession Number
13045
Title Of Article Chaper
Simulation of effects of uneven moisture profiles at the press section
Title Of Journal Book
TAPPI
Volume
66
Issue
3
Pages
156-158
Collation
Diagram,,table
Literature Type
Serial
Literature Level
Analytic
Abstract
Uneven moisture profiles in the sheet emerging from the press section are often the source of quality problems in the finished sheet. Little is known about the exact cause of these difficulties, but one possibility would be that significant differential stresses and strains are set up in open draws of the machine, thus leading to internal disruption and distortions of the wet web. Such differential stresses and strains are difficult to measure on a paper machine, and one logical approach would be to first conduct a simulation to determine whether indeed this would be an area in which a concerted effort should be made to develop suitable measuring techniques. A simulation employing the finite element technique involved the analysis of two models describing two typical conditions: a dry edge and a wet streak. In both cases, the solids content extremes were 2% apart (38% versus 40%). The model sheets were subjected to loading distributions designed to create an even strain (about 2. 2%) across the sheet. In both cases, the crossmachine direction strain turned out to be very uniform across the sheet (about 1.0%). In addition, cross-machine stresses and shear stresses were consistently about two orders of magnitude smaller than the machine-direction stresses and thus presumably not sufficiently great to create internal disruptions in the wet web. -- AATA
pub_id
51173