Design of 3D Shell-Graded Infill Structures Based on Moving Morphable Void and Triply Periodic Minimal Surfaces
摘要
Three-dimensional shell-porous structures are extensively utilized in aerospace, advanced manufacturing, and biomedical engineering due to their outstanding mechanical properties and lightweight characteristics. This paper presents a topology optimization framework for three-dimensional shell-graded porous structures, which integrates Triply Periodic Minimal Surfaces (TPMS) and the Moving Morphable Void (MMV) method, complemented by Problem-Independent Machine Learning (PIML) to enhance optimization efficiency. The MMV method is used to explicitly define the macroscopic topology, facilitating the direct generation of shell structures with well-defined boundaries and eliminating the need for post-processing. A Partitioned Coordinate Mapping (PCM) mechanism is introduced, employing TPMS functions to construct the spatially graded infill structure, while smooth geometric transitions between adjacent microstructures are ensured through the high-order continuity of Non-Uniform Rational B-Splines (NURBS) basis functions. To overcome computational challenges associated with full-scale analysis of complex lattice structures, a PIML framework is employed to accelerate the structural optimization process. A numerical example is given to validate the effectiveness of the proposed method.