Dear students,
Some calls for proposals may still be in preparation. Initiative enquiries can be directed to the academic staff if you cannot find a suitable thesis here.
Hot-melt bonding and ultrasonic welding of highly filled graphite-PPS for use in heat exchangers
Research Project, Bachelor Thesis
Highly filled graphite-polyphenylene sulphide (PPS) has enhanced thermal conductivity, making it particularly suitable for heat exchangers and thermal management in electronics, mobility and mechanical engineering. Joining this material is challenging, primarily due to the brittleness and low surface energy of PPS. The aim of the thesis is to develop a robust process window for hot-melt bonding and ultrasonic welding, as well as to evaluate the mechanical and microstructural properties of the joint zone with a view to heat exchanger-related applications. The thesis will be supervised in collaboration between the WKK and LRF departments. This will provide you with combined insights into process engineering and materials science! The thesis is highly practice-oriented and will take place predominantly in the laboratory.
Contact: Moritz Liesegang, Simon Ettmüller
Characterization of the electrical and magnetic material properties during high-frequency fatigue of WAAM-fabricated CrNi steels
Bachelor Thesis, Master Thesis, Diploma Thesis
Besides topology optimization, Additive Manufacturing allows for the targeted adjustment of material composition and, consequently, material properties. Knowing the relationship between these factors is therefore essential for producing such structures. As a basis for designing these graded structures, the magnetic, electrical, and mechanical properties of additively manufactured 316L and 17-4PH samples will be determined as a function of the build direction. Additionally, the local change in properties during cyclic loading is to be analyzed in interrupted tests. These findings will then serve as the basis for manufacturing graded structures.
Contact: Marc Alexander Hoffmann
Investigation of the fatigue behaviour of additively manufactured complex helix specimens made of AISI 316L
Master Thesis, Diploma Thesis, Bachelor Thesis, Research Project
The complex geometries of additively manufactured structures result in stress states with different proportions of tensile/compressive, bending and torsional stresses, which is why the relationship between the stress state and the component strength must be worked out for the design. Based on this background, uniaxially loaded specimens with complex geometry, which also resulted in considerable bending and torsional stresses, are to be analysed to what extent the stress state is related to the resulting strength. On this basis, a corresponding design approach will also be validated.
Contact: Paula Rahm
Interfaces in composite materials and multi-material joints
Masterthesis
Many properties of composite materials and material composites are determined by the interfaces between the individual materials. The aim of this thesis is to analyse the interfaces of ultrasonically welded composite materials in detail and correlate them with process parameters.
Contact: Moritz Liesegang
Frequency dependence of plastic deformability during ultrasonic welding of metals
Masterthesis
Ultrasonic welding is an innovative and promising joining technique for hybrid material systems. The joining of dissimilar material types is interesting for high-performance structures, e.g. in electronics or aviation. The plastic deformability of metallic joining partners during the process is a basic prerequisite for a successful process and the production of robust welded joints. This work therefore aims to investigate the plastic deformation of metal-safe materials during the ultrasonic welding process as a function of the working frequency.
Contact: Moritz Liesegang
Design of ultrasonic welding sonotrodes
Bachelor thesis or research project for Master students
Sonotrodes are tools that transmit the vibration into the components during ultrasonic-assisted processes such as ultrasonic welding. To do this, the sonotrode must be acoustically designed so that the natural frequencies match those of the rest of the system. The design is comparatively complex, depending on the geometry of the sonotrode and the material used, and is typically carried out using finite element simulation.
In this work, ultrasonic welding sonotrodes are to be designed using CAD and FEM, which differ in terms of geometry and the materials used.
Contact: Moritz Liesegang
Ultrasonic welding of metal/glass-joints - Interface formation
Bachelor thesis or research project for Master students
Ultrasonic welding is a fast method of joining multiple materials. Brittle materials such as glass are challenging but desirable joining partners. In particular, the understanding of glass as a joining partner is interesting due to its state as an overcooled melt rather than a solid material. In this work, experiments will be carried out on the joining of metal and glass, which has been the focus of research at the WKK decades ago, with a focus on interface formation.
Contact: Moritz Liesegang