Numerical evaluation of interfibre joint strength measurements in terms of three–dimensional resultant forces and moments
2012 (English)Report (Other academic)
The interfibre joint is one of the key elements in creating the strength of self–binding fibrous materials such as paper and board. In order to tailor the properties of such materials by chemical and/or mechanical treatments of the fibres, and to learn how such modifications influence the properties at the microscopic level, a greater understanding of how to evaluate the mechanical properties of interfibre joints is desirable. The methods reported in the literature for determining of the interfibre joint strength do not in general distinguish between the contributions of normal and shear stresses in the bonded region. This paper presents a numerical analysis procedure, based on the finite element method, for evaluating interfibre joint strength measurements in terms of the normal, shear, and moment loading components during testing. The method is applied to investigate the strength of Kraft pulp interfibre joints under two principally different modes of loading. The results show that for a typical interfibre joint test of an isolated fibre–fibre cross with long free fibre segments, modes of loading other than pure shear cannot, in general, be neglected, and are strongly dependent on the structural geometry of the fibre–fibre crosses. In addition, the resultant forces and moments were scaled in terms of the interface area and the twisting and bending resistance of the interface approximated as an ellipse to account for differences in interface area between the measurements. These scaled resultants were used to quantify how the mode of loading influences the relation between the amount of normal stress and the amount of shear stress that develop in the interfibre joint.
Place, publisher, year, edition, pages
KTH Royal Institute of Technology, 2012. , 37 p.
Trita-HFL. Report / Royal Institute of Technology, Solid Mechanics, ISSN 1654-1472 ; 528
fibre-fibre cross, fibre-fibre joint, finite rotations, interfibre joint strength, mode of loading, paper mechanics, paper strength
Paper, Pulp and Fiber Technology
IdentifiersURN: urn:nbn:se:kth:diva-116696OAI: oai:DiVA.org:kth-116696DiVA: diva2:600378
FunderSwedish Research Council, 2007-5380