Lightweight Design of Aircraft Engine Pylon Using Multi-Load Topology and Size Optimization

The lightweight design of an aircraft engine pylon requires an efficient structural layout capable of accommodating multiple load cases. An integrated lightweight design framework combining multi-load topology optimization and size optimization is developed. The three-field SIMP method with a weighted-compliance objective is employed to identify the dominant load-transfer paths under multiple representative load cases. Based on the resulting topology, a parametric model is constructed and optimized to reduce structural mass subject to strength and manufacturability constraints. The optimized member dimensions are subsequently used to reconstruct an engineering-manufacturable pylon configuration, whose structural performance is evaluated through finite element analysis. The results demonstrate that the multi-load topology optimization produces a stable primary load-bearing framework, while the subsequent size optimization reduces the structural mass from 238 kg to 156 kg, a reduction of 82 kg. The proposed framework provides a practical route for the lightweight design of aircraft engine pylons and can serve as a reference for other complex aerospace load-bearing structures.