Material Model for Anisotropic Viscoelasticity at Finite Deformations Applied to Pulp Fibres

The goal of this thesis is to find a material model that is capable of describing the
behaviour of a pulp fibre. In the first major part of this thesis a general introduction to finite element analysis is given and the constitutive equations of the used material model are described. In the second major part the calibration of the material model parameters with nano indentation experiments is outlined.

An anisotropic viscoelastic material model for finite deformations is implemented into a finite element Matlab source code SOOFEA and in a user subroutine of ABAQUS. This implementation is then used to simulate nano indentations experiments. By iteratively adapting the material parameters the simulation results are fitted to the real experimental values. With that proceedure the material parameters can be calibrated.