Topology Optimization of an Aircraft Part & L-PBF Processing of High-Strength Aluminum Alloys

Details

Supervisors

Simar, Aude

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

Weight reduction is a major objective in aerospace engineering, and Laser Powder Bed Fusion offers new possibilities for producing lightweight metallic structures with complex geometries. However, the combination of topology optimization and Laser Powder Bed Fusion remains challenging because optimized geometries must satisfy mechanical requirements while remaining compatible with the manufacturing process and suitable processing conditions. The objective of this thesis was to investigate the use of topology optimization and Laser Powder Bed Fusion for lightweight aluminum aerospace structures, with a focus on an industrial aircraft slat track rib and on the processing of AlSi10Mg and Al7075+Zr+Zn+Mg. A density-based topology optimization framework was adapted to an industrial geometry provided by SONACA. The framework was extended to include several load cases, stress constraints, non-design regions, and manufacturability constraints related to Laser Powder Bed Fusion, namely a minimum feature size constraint. In parallel, dimensionless melting mode processing diagrams were reconstructed for AlSi10Mg and Al7075-based alloys using literature data and experimental samples characterized at UCLouvain. Finally, the optimized geometries were reconstructed in three dimensions, and manufactured by Laser Powder Bed Fusion using AlSi10Mg powder. Two optimized designs were obtained using the mechanical properties of Al7075+Zr+Zn+Mg. The aggressive design achieved a mass reduction of approxi mately 33%, while the conservative design achieved a reduction of approximately 12% compared with the reference part. This mass reduction was obtained at the cost of increased compliance, especially for the aggressive design. The comparison between Al7075+Zr+Zn+Mg and AlSi10Mg showed that the higher yield strength of Al7075+Zr+Zn+Mg is more suitable for aggressive lightweight designs. The reconstructed processing diagrams identified high-density regions, especially near the onset of transition melting for AlSi10Mg, but their predictive use remains limited by the difficulty of predicting absorptivity. Overall, this work showed that topology optimization and Laser Powder Bed Fu sion can be combined to generate and manufacture promising lightweight aerospace structures. However, the optimized designs were not mechanically validated, and further work should include three-dimensional optimization, refined stress analysis, mechanical testing, improved support strategies, and manufacturing trials using Al7075+Zr+Zn+Mg.