The influence of strain rate and pulp properties on the stress-strain curve and relaxation rate of wet paper

Research output: Contribution to journalArticleScientificpeer-review

2 Citations (Scopus)

Abstract

Sufficient tension of the wet web is crucial for paper machine runnability. As profitability pressures have been increasing, the potential to improve runnability is of interest. The runnability of wet paper is especially important for paper machines running at high speeds, making paper at lower grammage, and using large amounts of filler or recovered paper. The typical location of web breaks depends on the paper grade and paper machine. A break typically takes place when the paper is wet and a fast draw is applied to the web. Because information on wet paper is scarce, especially information on the effect of strain rate on the tensile properties, we investigated the effects of strain rate on the tension-strain curve and relaxation of wet paper and how they depend on pulp type, refining, solids content, and fines. Higher strain rate leads to higher tensile strength, tensile stiffness, and relaxation rate. The initial wet strength and stiffness of the studied pulps, bleached softwood kraft pulp and bleached hardwood kraft pulp, were increased by increasing the solids content, fines, wet pressing, and refining. At a constant strain rate and constant strain, the tension at a certain moment depended strongly on the initial tension and thus on the tensile stiffness.
Original languageEnglish
Pages (from-to)515-524
JournalTappi Journal
Volume14
Issue number8
Publication statusPublished - 2015
MoE publication typeA1 Journal article-refereed

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Stress-strain curves
Pulp
Strain rate
Kraft pulp
Stiffness
Refining
Bleached pulp
Softwoods
Hardwoods
Tensile properties
Fillers
Profitability
Tensile strength

Cite this

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title = "The influence of strain rate and pulp properties on the stress-strain curve and relaxation rate of wet paper",
abstract = "Sufficient tension of the wet web is crucial for paper machine runnability. As profitability pressures have been increasing, the potential to improve runnability is of interest. The runnability of wet paper is especially important for paper machines running at high speeds, making paper at lower grammage, and using large amounts of filler or recovered paper. The typical location of web breaks depends on the paper grade and paper machine. A break typically takes place when the paper is wet and a fast draw is applied to the web. Because information on wet paper is scarce, especially information on the effect of strain rate on the tensile properties, we investigated the effects of strain rate on the tension-strain curve and relaxation of wet paper and how they depend on pulp type, refining, solids content, and fines. Higher strain rate leads to higher tensile strength, tensile stiffness, and relaxation rate. The initial wet strength and stiffness of the studied pulps, bleached softwood kraft pulp and bleached hardwood kraft pulp, were increased by increasing the solids content, fines, wet pressing, and refining. At a constant strain rate and constant strain, the tension at a certain moment depended strongly on the initial tension and thus on the tensile stiffness.",
author = "Jarmo Kouko and Elias Retulainen",
note = "HUO: PowerBonds project belonging to the EU WoodWisdom-Net program. Project code: 74054",
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journal = "Tappi Journal",
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The influence of strain rate and pulp properties on the stress-strain curve and relaxation rate of wet paper. / Kouko, Jarmo; Retulainen, Elias.

In: Tappi Journal, Vol. 14, No. 8, 2015, p. 515-524.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The influence of strain rate and pulp properties on the stress-strain curve and relaxation rate of wet paper

AU - Kouko, Jarmo

AU - Retulainen, Elias

N1 - HUO: PowerBonds project belonging to the EU WoodWisdom-Net program. Project code: 74054

PY - 2015

Y1 - 2015

N2 - Sufficient tension of the wet web is crucial for paper machine runnability. As profitability pressures have been increasing, the potential to improve runnability is of interest. The runnability of wet paper is especially important for paper machines running at high speeds, making paper at lower grammage, and using large amounts of filler or recovered paper. The typical location of web breaks depends on the paper grade and paper machine. A break typically takes place when the paper is wet and a fast draw is applied to the web. Because information on wet paper is scarce, especially information on the effect of strain rate on the tensile properties, we investigated the effects of strain rate on the tension-strain curve and relaxation of wet paper and how they depend on pulp type, refining, solids content, and fines. Higher strain rate leads to higher tensile strength, tensile stiffness, and relaxation rate. The initial wet strength and stiffness of the studied pulps, bleached softwood kraft pulp and bleached hardwood kraft pulp, were increased by increasing the solids content, fines, wet pressing, and refining. At a constant strain rate and constant strain, the tension at a certain moment depended strongly on the initial tension and thus on the tensile stiffness.

AB - Sufficient tension of the wet web is crucial for paper machine runnability. As profitability pressures have been increasing, the potential to improve runnability is of interest. The runnability of wet paper is especially important for paper machines running at high speeds, making paper at lower grammage, and using large amounts of filler or recovered paper. The typical location of web breaks depends on the paper grade and paper machine. A break typically takes place when the paper is wet and a fast draw is applied to the web. Because information on wet paper is scarce, especially information on the effect of strain rate on the tensile properties, we investigated the effects of strain rate on the tension-strain curve and relaxation of wet paper and how they depend on pulp type, refining, solids content, and fines. Higher strain rate leads to higher tensile strength, tensile stiffness, and relaxation rate. The initial wet strength and stiffness of the studied pulps, bleached softwood kraft pulp and bleached hardwood kraft pulp, were increased by increasing the solids content, fines, wet pressing, and refining. At a constant strain rate and constant strain, the tension at a certain moment depended strongly on the initial tension and thus on the tensile stiffness.

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