Two-scale topology of optimization of functionally graded lattice structures with varying volume fraction - 变体分比功能梯度点阵结构两尺度拓扑优化设计

Functionally graded lattice structures enjoy widespread attention due to their lightweight, high specific stiffness/strength, high fracture resistance and other good performances, yet design optimization of these structures is still a challenging task due its cross-scale and spatially graded geometrical characteristics. In this
work, a two-step optimization strategy is proposed to design functionally graded lattice structures. In the first step, the Discrete Material Optimization (DMO) is conducted to obtain optimal macro structural configuration and micro structural distribution. In the second step, parametric optimization is conducted to obtain graded lattice structures with varying volume fraction. The advantage of this work includes the adoption of the varying volume
fraction operation, which enables the management of complex microstructures, and the pattern of spatially graded microstructure, which further broadens design space and improves structural stiffness, facilitating efficient use of materials. Finally, several numerical examples are presented to verify the effectiveness of the proposed method which significantly expands design space and effectively improve the structural stiffness.