Optimization of Large-scale Aeroengine Parts Produced by Additive Manufacturing

Abstract

Additive Manufacturing (AM) presents a ground-breaking opportunity to produce lightweight parts with enhanced functionality and design flexibility. It revolutionizes assembly by enabling integrated designs that significantly reduce component counts, minimizing assembly efforts and potential faults. Consequently, AM stands out as an appealing choice for manufacturing aerospace engine parts. Among AM techniques for metal parts, Laser Powder Bed Fusion (LPBF), also known as Direct Metal Laser Melting (DMLM), currently dominates the industry due to its capability to achieve high part quality and density using advanced machinery. However, limitations in part size stem from the build envelopes of these machines. Hence, this study explores the feasibility of printing large-scale engine parts, covering the design process, additive manufacturing, and aerothermal testing. A turbine center frame, nearly one meter in diameter, serves as a demonstrator case. Employing a multi-objective Design for Additive Manufacturing (DfAM) approach, the frame’s structure underwent optimization through generative design, aiming to minimize mass, maximize stiffness, and meet strength requirements. Furthermore, the manifold section of the frame was optimized to reduce system pressure loss within the designated design space. Inconel 718 using LPBF was selected, with initial segments confirming manufacturability. The manufacturing process was fine-tuned for productivity and part properties, establishing design guidelines accordingly. Subsequently, the optimized manifold design underwent successful aerothermal testing on a specific test rig under various flow conditions. The redesigned frame showcased a 34% weight reduction and a 91% decrease in pressure loss while consolidating over 100 parts into one assembly. For the production, two alternatives are discussed. On the one hand, the final design was printed using the GE Additive ATLAS, the largest available LPBF system, validating the AM feasibility for large-scale parts under controlled laboratory conditions. On the other hand, a modified design is proposed that allows for the printing of segments on a regular-sized AM machine and a subsequent welding.