The common modelling approach is to consider the printed structure as a composite laminate. Such models cannot capture the complex behaviour of FDM materials beyond the linear elastic regime. It can only be understood by considering nonlinear effects at the mesostructure, which needs to be interpreted as a 3D structure of bonded fibres rather than an anisotropic solid. 

Based on these observations, new theoretical and computational frameworks are developed. All approaches represent the mesostructure as an arrangement of beams and consider debonding and fracture of these beams.

Developing reliable numerical simulation of heat transfer during fused filament fabrication (FFF) to enable more accurate predictions of process-induced residual stresses, bonding quality, and the mechanical performance of printed components.

A key objective is to increase computational efficiency without compromising the physical accuracy of the deposition process, for example through adaptive mesh coarsening and advanced element activation strategies.

The thermal interaction between the printed part and its environment is investigated by calibrating thermal boundary conditions based on experimental measurements.

It is further examined how infill geometry, density, and air-filled structures influence heat transfer and identify simplified yet reliable modeling approaches for these complex internal features. Together, these developments provide a more efficient and experimentally validated simulation framework for predicting the thermal behavior of FFF processes, supporting the design of more reliable and higher-quality additively manufactured parts.

Investigating the origin and evolution of stresses during the material extrusion process in fused filament fabrication (FFF), which are a major cause of defects such as warpage, shrinkage, and delamination.

Using advanced finite element simulations combined with experimental validation, it is analyzed how stresses develop within an extruded filament as it cools and solidifies. Different material models are compared to accurately capture the thermo-mechanical behavior of the polymer during deposition.

The influence of key process parameters, including printing speed as well as nozzle and build plate temperatures, is systematically evaluated. The results provide a deeper understanding of stress formation during extrusion and support the optimization of process parameters to improve the dimensional accuracy and quality of additively manufactured components.