Masterarbeit (laufend)

Arshia Vali Pour

Numerical investigation of out-of-plane deformation and failure in cellulose fiber networks

Cellulose-based materials, including paper and paperboard, are increasingly used in sustainable technologies due to their renewable origin and biodegradability. Beyond their conventional role in packaging, particularly food packaging, these materials are now employed in structural applications, and emerging fields such as paper-based electronics and sensors. Computational methods have therefore been employed to optimize the design of both these materials and the products made from them. The multi-physics and multi-scale nature of paper renders numerical modeling particularly challenging and complex. Paper and paperboard can be modeled at different scales of interest-fiber, network, sheet, and laminateeach of which reveals distinct aspects of the material's mechanical behavior and carries its advantages and limitations.
The bond between fibers and the three-dimensional network structure formed during manufacturing are key factors governing paper extensibility. Studying this fiber network structure is therefore essential for understanding the mechanical behavior of paper. Although the in-plane mechanical behavior of cellulose fiber networks has been widely studied, their out-of-plane response remains less understood, despite its importance in applications such as forming processes.
The objective of this thesis is to develop a computational framework for simulating the out-of- plane mechanical behavior of 3D cellulose fiber networks, with a focus on investigating the relationship between microstructural cohesive properties and macroscopic properties such as fracture toughness.
This thesis is conducted as an external collaboration between the Chair of Computational Applied Mechanics at the University of Wuppertal (Prof. Dr.-Ing. habil. Jaan-Willem Simon), and the Chair of Mechanics - Materials Theory (Prof.'in Dr.-Ing. Johanna Waimann), under the supervision of M.Sc. Jan Mirco Pfeifer and Dr.-Ing. Johannes Neumann.