Local network effects on hygroscopic expansion in digital ink-jet printing
Emanuela Bosco, Ron Peerlings and Marc Geers, Eindhoven University of Technology, Eindhoven, Netherlands
Dimensional stability of paper is a key problem in the field of digital ink-jet printing. In the literature, this phenomenon is mostly approached through continuum models representing the overall response of paper. However, if the length scale of the applied wetting is comparable to the characteristic length scale of the microstructure a continuum description may be not sufficient to correctly capture the response of the material. The present work explores this question by proposing a two dimensional fibrous network model, which investigates the hygro-expansion phenomena due to the printing process and their effects on the local response of the paperís microstructure. The proposed description incorporates several microscale features, such as the fibre hygro-elastic properties, orientation, areal coverage. Different moisture patterns are applied to the fibrous networks, allowing to study their behaviour as a function of the coverage, the anisotropic orientation and the size of the wet regions relative to the fibre length. A comparison with a homogenized continuum model is finally performed. This reveals that, for low coverages, a microstructural approach is substantially more accurate, whereas for denser networks the continuum model is a valid alternative, even when the size of the wetting pattern becomes comparable to the fibre length.
Fibrous network, Hygroexpansion, Local deformations, Local stresses, Printing
Nordic Pulp & Paper Research Journal (NPPRJ) is an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents, pulp and paper and including new fiber-based materials, recovery and by-products from pulping processes, bio-refining and energy issues. Articles meeting required scientific standards are accepted from any continent. Open Access: Articles not available through Gold Open Access may be purchased by credit card as a pdf file, to be downloaded within 24 h after ordering, at a price of 22 EUR per article. (Value added tax may apply depending on your location, which you enter at payment logout.) Such articles have Green Open Access, i.e. authors may share articles on their personal non-commerical homepage immediately after publication on the website and download them to non-commercial hosting platforms one year after publication in a full issue of NPPRJ. ISSN: 0283-2631