Paper materials possess usually cellulose fiber networks complemented with pore structure on the microscopic scale. Both the mechanical property and durability of papers, which are vital for the processibility and serviceability of the materials, strongly depend on the properties of the constitute fibers, fiber-fiber bonds and fiber network with microscopic details. Moreover, in order to reveal the impact of the designed chemical and consequently mechanical modifications of fiber-fiber bonds within the PAKET-proposals, a model allowing direct access to these microscopic aspects is indispensable. The microscopic features of the pore structure and their change are also important for the understanding of the functionality of papers like fluidics.

The aim of this proposal is finite element simulations of micromechanical behavior of deformable fiber networks in paper materials. In particular, the mechanical deformation of the conventional and chemically modified fiber networks on the microscopic scale will be numerically revealed, under mechanical loading and subjected to dry and wet conditions, respectively. Particularly, physically motivated and experiment-based models will be developed for fibers, fiber-fiber bonding interfaces or interphases, and fiber network distribution. Simulation results should also provide useful information for better understanding and prediction of the pore structure changes on the microscopic level of the functional paper.