The Vertex Effect in Polycrystalline Materials

Acknowledgements Soli Deo Gloria. The work presented in this thesis has been done during my time as a research staff member at the Otto-von-Guericke-Universität Magdeburg. I am indebted to Prof. Albrecht Bertram, who was the advisor and the first referee of this thesis. He was a guide in finding the topic of the work and finally finishing it. His mentorship by teaching the theoretical foundations of continuum mechanics and widening the view by stimulating a variety of contacts was a great experience. I also wish to thank Prof. Henryk Petryk, Polish Academy of Science, for the supportive discussions on the general topic and several aspects of the work, and for being the second referee. I enjoyed being a member of a team of great colleagues. In particular, I wish to thank Enrico Brosche for his help with numerical integration. I would like to mention the support and the interdisciplinary discussions as an associated member in the Graduate School " Micro-Macro-Interactions in Structured Media and Particle Systems " , supported by DFG. Last but not least I wish to express my deepest gratitude to my beloved wife Doris, who cared for our children Lisa and Julius and by this gave me the opportunity to work on this thesis.