1. The ideal candidate is highly motivated, enthusiastic and communicative researcher with a Masters degree in Mechanical Engineering, Materials Engineering, or a closely related field. They have experience with mechanical testing and are familiar with Additive Manufacturing processing conditions, or are eager to educate themselves on these topics. They have obtained their degree with distinction or the equivalent thereof, and are able to work independently on this PhD project, as well as collaborate with fellow researchers in the AM group, the CUSTOM doctoral network, and beyond.
2. Candidates should have experience with experimental work, and materials characterization techniques (metallography, …). Specific experience with metal additive manufacturing is a plus.
3. Applicants should have excellent oral and written English communication skills (TOEFL score of at least 94 or IELTS-score of 7 or higher).
4. The successful candidate is expected to contribute to education at the Bachelor or Master level (master thesis supervision, teaching of exercise or practical sessions, …)
5. Specifically for the MSCA doctoral network, there is a requirement that applicants for this position cannot have resided or carried out their main activity (work, studies, etc.) in Belgium for more than 12 months in the 36 months immediately before their recruitment date. Moreover, applicants cannot have previously obtained a PhD.
The CUSTOM project is a Marie Skłodowska-Curie Actions (MSCA) Doctoral Network unites three core disciplines (design, manufacturing, and testing) towards the development of a next generation of patient-specific shoulder implants. The number of shoulder replacements is projected to increase by 300-400% between 2020 and 2040. With the current technology, 10% of those artificial shoulder implants will fail within the first 10 years of service, mainly due to soft tissue failure, infection, and implant loosening. CUSTOM focuses on combining (1) computational tools that allow patient-specific design, (2) additive manufacturing to realize the custom, complex designs and structures and their further postprocessing to incorporate multi-functionality, and (3) blended in-silico and experimental testing to reduce the burden on experimental testing for certification. In doing so, CUSTOM can address the major failure mechanisms of current shoulder implants and improve their overall functionality and longevity.
Additive manufacturing or AM is a key enabling technology to create patient-specific implants. For the purpose of the implants, controlled porous structures, also known as lattice structures, provide benefits such as minimizing stress shielding, and improved osseointegration. While the mechanical behavior of such lattice structures is partially understood, the sheer number of different lattice structure designs, in combination with the complex multi-axial load patterns that mimic the typical loading of a shoulder joint, mean that we do not yet know how such implants would mechanically behave in the long run.
This doctoral project therefore aims to determine the anisotropic mechanical behaviour of engineered porous structures under multiaxial torsion + tension/compression loading conditions, including: (1) Laser Powder Bed Fusion (LPBF) process investigation towards generic parameter optimization for various types of lattice structures, specifically high relative density structures (>50% relative density). (2) Fabrication of test specimens with suitable geometry for multi-axial load testing. (3) Investigate the effect of lattice orientation with respect to the loading directions in multi-axial loading. (4) Determine optimal lattice density and type for best quasi-static and dynamic behaviour, matching the intended use case, which is the replacement of human bone and/or cartilage in this project. Worthy to note is that the methodology and mapping of the process-structure-properties relations for these structures extends beyond the application in orthopaedic implants, and could also be applied, for example, in lightweighting applications in aviation and aerospace.
The project includes two research stays of three months. A first secondment at Amnovis in Belgium to produce samples with alternative geometries and assess their behavior in multi-axial loading, as well as a secondment at Semmelweiss University in Budapest, Hungary to perform accelerated corrosion testing on samples produced at KU Leuven, to investigate the effect of corrosion on the mechanical behavior.
This PhD position is hosted by the Additive Manufacturing (AM) research group, under the direct supervision of both Prof. Bey Vrancken and Prof. Brecht Van Hooreweder – as part of the Manufacturing and Process Systems division (MaPS) at the Department of Mechanical Engineering, KU Leuven. The KU Leuven AM group has over three decades of expertise in AM research. At present, the AM group is continuing and extending their research activities in different areas related to laser-based AM (see also the research group website): broadening the materials palette for AM (ceramics, aluminum, bio materials, …); relating process conditions to static and dynamic mechanical properties via analysis of micro structure, texture, porosity, thermal stresses,…; machine design and process optimization (software and hardware, integrating new enabling technologies); and in-situ and post-process quality control (X-ray CT, process monitoring, closed loop control, post-build treatments). This Ph.D. position is offered through the Marie Skłodowska-Curie Actions (MSCA) Doctoral Network 'CUSTOM'. Vacancies for other Ph.D. topics within this network can be found on the project's website.
We offer:
6. A doctoral scholarship (fully funded) and a Ph.D. degree in Engineering Science if successful.
7. A highly specialized doctoral training in an international environment at a top European university, as well as through the MSCA doctoral network CUSTOM.
8. Extensive training and networking activities via the MSCA Doctoral Network 'CUSTOM' project, which involves a total of 17 doctoral candidates.
9. A living allowance, mobility allowance and, if applicable, family, long-term leave and special needs allowances.
10. The opportunity to participate in research collaborations and international conferences.
11. A stepping stone towards future career opportunities in the European R&D sectors.
12. A stay in a vibrant environment in the heart of Europe. The university is located in Leuven, a town of approximately 100000 inhabitants, located close to Brussels (25 km), and 20 minutes by train from Brussels International Airport. This strategic positioning and the strong presence of the university, international research centers, and industry, lead to a safe town with high quality of life, welcome to non-Dutch speaking people and with ample opportunities for social and sport activities. The mixture of cultures and research fields are some of the ingredients making the university of Leuven the most innovative university in Europe.