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- ItemMulti-Material Topology Optimization for IPM Machine with Efficient Rare-Earth PM Utilization(New York, NY : IEEE, 2025-10-14) Mahmoud, Mohamed Reda; Ibrahim, Mohamed N.; Sergeant, PeterThis paper presents a multi-material topology optimization (TO) to efficiently utilize rare-earth permanent magnet (REPM) material and improve the machine performance. The proposed approach employs a density-based TO method to optimize the multi-material distribution inside the rotor domain. The TO algorithm optimally redistributes air, silicon-steel, and REPM. The objective function of the TO is to maximize the average torque of the IPM motor while constraining the material volume of both silicon-steel and REPM to below that utilized in the conventional design. The results demonstrate that multi-material TO is a highly effective strategy for developing a new generation of sustainable electric machines. The topology optimized configuration achieved an approximate 4% increase in torque density while reducing the amount of REPM used by 12.5%. Moreover, the amount of silicon steel required for the optimized rotor is 9% lower than the conventional design.
- ItemTopology Optimization for Enhancing Electric Machine Performance: A Review(New York, NY : IEEE, 2024-09-01) Mahmoud, Mohamed Reda; Ibrahim, Mohamed N.; Sergeant, PeterExploring the design space is essential in the pursuit of developing high-performance and power-dense electric machines. This article explores the transformative potential of topology optimization (TO) in enhancing the performance of electric machines. Conventional techniques for optimizing the design of electric machines use optimization algorithms to determine geometric variables within a predefined range. However, these methods are limited by manufacturing constraints and the designer's expertise in parameterization. On the other hand, topology optimization aims to enhance the performance of electric machines by manipulating the distribution of materials as a design factor. The enhancement is facilitated by additive manufacturing (AM), particularly via the manufacturing of intricate metal parts. In this paper, the main concepts of topology optimization in electric machines are reviewed. Firstly, the requirement for topology optimization is illustrated, and both the achievements and challenges of this technique over the traditional parametric optimization are described. Then, a description is given of different topology optimization methods that were reported in the literature. Finally, the development opportunities of this technology are shown in the electric machine design field.
- ItemTopology Optimization for a Magnetic Actuator Using Different Gradient-Based Solvers(New York, NY : IEEE, 2025-01-13) Mahmoud, Mohamed Reda; Ibrahim, Mohamed N.; Sergeant, PeterThis paper presents a comparative study on the performance of density-based topology optimization using different gradient-based solvers. Three common solvers are employed: the method of moving asymptotes (MMA), interior point optimizer (IPOPT), and sparse nonlinear optimizer (SNOPT). The gradient solvers are compared regarding the convergence behaviour, computational time, and solution quality, i.e. maximizing the attractive force, when topology optimization is used to design a magnetic actuator as a case study. The results provide valuable insights into the strengths and limitations of MMA, IPOPT, and SNOPT in solving topology optimization and offering guidance for selecting the appropriate solvers. The results proved that SNOPT is suitable for largescale problems as it has fast convergence and low computation time compared to MMA and IPOPT solvers. Further, IPOPT is not suitable for large-scale problems due to high computation time and large amounts of intermediate materials, i.e. regions where the density function differs from 0 and 1. Moreover, the quality of the optimal solution is only slightly affected by the used solver.
- ItemReducing AC Joule Losses in Hairpin Windings of Electric Machines: Strategies for Minimizing Losses Due to Radial and Tangential Flux(New York, NY : IEEE, 2025-10-22) Bekele, Yitbarek; Korolova, Olga; Biebighäuser, Andreas; Akbar, Siddique; Ebrahimi, Amir; Ponick, BerndThis paper presents a comprehensive analysis of conductor design strategies to reduce joule losses in hairpin windings of high-speed permanent magnet synchronous machines (PMSMs). With the increasing demand for high torque density, efficiency, and high-speed operation in electric vehicles and aircraft, minimizing these losses is crucial. Starting with a reference winding layout, various loss mechanisms due to radial and tangential flux components are investigated using finite element analysis (FEA) under both no-load and short-circuit conditions. Design variants including adjustments to conductor geometry, slot opening shapes, layer-specific conductor height tuning and segmented conductor designs with overhang twisting are explored. The findings are relevant for improving the performance and manufacturability of electric machines, with additive manufacturing offering new design opportunities for enhanced efficiency and lower losses.
- ItemThe Evolution and Future of Composite Construction in Light Aircraft(Hannover : Technische Informationsbibliothek, 2025) Wu, WilliamWithin this study the historical development, current applications and future topics of light aircraft construction shall be analyzed. It describes the evolution of used materials and construction methods starting from traditional materials such as wood and aluminum to advanced composite materials. Furthermore, the different types of composite materials and construction methods are categorized, their advantages and disadvantages are discussed. The implementation in current aircraft models by leading manufacturers such as Diamond Aircraft, Cirrus, and Elixir is presented. Further, the challenges that likely arise with the adoption of advanced composites in general aviation are discussed and finally emerging trends and technologies that may be adapted in future aircraft construction are described.