3-D computational simulation of paper handsheet structure and prediction of apparent density

Abstract

To obtain a better understanding of the influence of fiber morphology on paper properties, a novel 3-D computational simulator of paper structure was developed and validated by experimental work. Depending on the wood species, the dimensions of the fibers may vary by a factor of two or three, which directly influences paper structure and properties. Using known fiber size distributions, the model creates virtual handsheets made of these pulps that can be visualized, manipulated, and qualitatively and quantitatively compared to real handsheets. For a given basis weight, the model calculates the number of fibers in the sample and the main textural properties: thick-ness, apparent density, porosity, and roughness. It also computes the relative bonded area and the apparent specific surface, which are important factors for assessing mechanical or transport properties. This simulator can be used to predict, in a very short time, the variation of a property as a function of changes in one morphological parameter such as fiber length. This paper presents the main principles of the simulation and the results for one global textural property, apparent density. A prediction of tensile breaking strength will be presented in a subsequent paper.