Multi-Material Conceptual Design of Aircraft Engine Pylon Based on Floating Projection

The development of multimaterial topology optimization offers significant advancements in the design of lightweight aerospace structures. A three-field multimaterial topology optimization method with a material selection function under a mass constraint is developed. By integrating a multimaterial linear interpolation model with floating projection techniques, design variables are refined to the expected 0/1 level, ensuring accurate smooth design. The approach demonstrates smooth convergence even when applied to more than three material phases, producing optimized structures with distinct material boundaries and interfaces. A case study of the aircraft engine pylon design is presented, utilizing real material properties, including Poisson's ratio, to meet lightweight design requirements. The requirement of lightweight design is realized by introducing effective lightweight materials and automatically adjusting the distribution and volume fraction of materials. Additionally, the three-field density representation technique is applied to improve the optimization efficiency and is extended to design considering manufacturing uncertainty. The robust manufacturing multimaterial structure is designed with the potential for manufacturing errors in mind. It can provide valuable guidance for multimaterial lightweight design of aerospace structures.