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The title of the thesis: Magneto-Mechanical Analysis and Manufacturing Integration of Multi-Material Rotor for High-Speed Synchronous Reluctance Machines

Thesis defender: Maksim Sitnikov
Opponents: 
Prof. Peter Sergeant, Ghent University, Belgium
Prof. Nora Leuning, RWTH Aachen University, Germany
Custos: Prof. Anouar Belahcen, Aalto University School of Electrical Engineering

This doctoral thesis investigates the magneto-mechanical design and manufacturing integration of multi-material rotors for high-speed synchronous reluctance machines. High-speed electric machines are increasingly used in energy, transportation, and industrial applications where compactness, efficiency, and reliability are critical. However, their rotors are subjected to extreme centrifugal forces while simultaneously required to maintain optimal magnetic performance. These competing demands make conventional design and manufacturing approaches insufficient.
The purpose of the study was to develop an integrated design methodology that simultaneously considers electromagnetic performance, mechanical strength, and industrial manufacturability. Particular focus was placed on rare-earth-free synchronous reluctance machines and on enabling solid, mechanically robust rotors through advanced multi-material solutions.
The research combines analytical modelling, finite element simulations, and experimental validation. A key contribution is the development of magneto-mechanical analysis methods that explicitly account for the interaction between electromagnetic loading and mechanical stresses at high rotational speeds. In addition, the thesis demonstrates a scalable manufacturing approach based on hot isostatic pressing of dissimilar materials, enabling the production of structurally integrated multi-material rotors.
The results indicate the feasibility of designing rotors that maintain high efficiency and torque performance while significantly improving mechanical robustness. The study also provides insight into the formation of residual stress in multi-material composites and its impact on electromagnetic behaviour. Importantly, the work bridges the gap between theoretical machine design and industrial-scale manufacturing.
The findings are directly applicable to the development of next-generation high-speed electric drives for energy-efficient industrial systems, electric mobility, and sustainable power technologies. By advancing rare-earth-free machine concepts, the research contributes to reducing dependence on critical raw materials and supports long-term technological resilience.
In conclusion, the thesis demonstrates that high-speed electric machines can be designed not only for peak performance, but also for manufacturability and material sustainability, establishing a coherent technological pathway from modelling to industrial implementation.

Key words: Additive manufacturing; High-speed; Magneto-mechanical coupling; Multi-material rotor; Synchronous reluctance machine

Thesis available for public display 7 days prior to the defence at .

Contact:

maksim.sitnikov@aalto.fi