Internship in Bio-inspired natural & cellulose fiber-reinforced composites with ductile behavior at Bremen City University of Applied Sciences Supervisor Prof. Dr.-Ing. Jörg Muessig & Dr.-Ing. Nina Graupner Project Bio-inspired natural & cellulose fiber-reinforced composites with ductile behavior Biological materials show impressive combinations of mechanical properties like strength and toughness and are optimized in the evolutionary process to meet nature’s requirements. For engineering materials, there is more to learn from nature than replicating one structure: learning from the general principles and structural hierarchy of these natural materials can give valuable ideas, for example, for the improvement of mechanical properties of materials. Natural solutions as concept generators for technical composites, should lead to a further optimization of the mechanical properties of cellulose fiber-reinforced composites. The advantages of different reinforcing fibers are brought together in one composite. Bast fiber-reinforced composites generally display good strength and stiffness with brittle impact behavior at the same time. In contrast to this regenerated cellulose fiber-reinforced composites show a high ductility and good impact properties. A previous work has shown that a mixture of both types of fibers lead to a significant improvement of the impact properties compared to bast fiber-reinforced composites. A further improvement of these properties has been succeeded by using natural solutions. Nature offers several examples, which are optimized to stress as well as impact. For example, symmetric layered structures in the petioles of red rhubarb, or even asymmetrical layers in the pericarp of the coconut. These structures were transferred to technical solutions and have been implemented in compression molded layered composites by using ramie (high stiffness, low elongation), hemp (lower stiffness and higher elongation compared to ramie) and lyocell fibers (lower stiffness and higher elongation compared to hemp) as reinforcement for a plastic matrix. The results have shown that the impact properties could be significantly improved by such a layered structure compared to composites which were produced from a mixture of the different fibers. The tensile characteristics were not affected by the layered structure. The investigations show that the concept of the development of biomimetic fiber composites can result in an optimization of the mechanical characteristics of classical composites. The unusual structures from the engineering point of view of the red rhubarb petioles and the fruit shell of the coconut have led to a further optimization of cellulose fiber-reinforced PLA composites. Apart from these two examples there are many interesting biological structures which may be used to improve the characteristics of cellulose fiber-reinforced composites. If you are interested in such research projects do not hesitate to contact us! Student projects are offered in ongoing research and development projects on bio-based and bio-inspired composites. Tasks Analysis of biological structures Fiber and composite characterization Composite manufacturing and testing Requirements Material science background Engineering background and/or Biology background good analytical skills practical skills for laboratory flexibility and high motivation Language Skills Fluent English (reading, writing, speaking) required, basic German (talking, reading) preferred. Duration 3 - 6 months Possible Beginning Anytime According to agreement Credits Report or final thesis, depending on conditions for recognition at the home institution. Payment If the project has third-party financing at the time of the internship. Possibly as a student co-worker.