Lattice-skin structures composed of a thin-shell skin and a lattice infill are widespread in nature and large-scale engineering due to their efficiency and exceptional mechanical properties. Recent advances in additive manufacturing, or 3D printing, make it possible to create lattice-skin structures of almost any size with arbitrary shape and geometric complexity. We propose a novel gradient-based approach to optimising both the shape and infill of lattice-skin structures to improve their efficiency further. The respective gradients are computed by fully considering the lattice-skin coupling while the lattice topology and shape optimisation problems are solved in a sequential manner. The shell is modelled as a Kirchhoff-Love shell and analysed using isogeometric subdivision surfaces, whereas the lattice is modelled as a pin-jointed truss. The lattice consists of many cells, possibly of different sizes, with each containing a small number of struts. We propose a penalisation approach akin to the SIMP (solid isotropic material with penalisation) method for topology optimisation of the lattice. Furthermore, a corresponding sensitivity filter and a lattice extraction technique are introduced to ensure the stability of the optimisation process and to eliminate scattered struts of small cross-sectional areas. The developed topology optimisation technique is suitable for non-periodic, non-uniform lattices. For shape optimisation of both the shell and the lattice, the geometry of the lattice-skin structure is parameterised using the free-form deformation technique. The topology and shape optimisation problems are solved in an iterative, sequential manner. The effectiveness of the proposed approach and the influence of different algorithmic parameters are demonstrated with several numerical examples.
翻译:由薄壳皮肤和拉特板装饰构成的拉特板结构在性质和大规模工程上十分广泛, 由于其效率和特殊的机械特性, 大型工程也十分广泛。 添加剂制造或 3D 印刷的最新进展使得有可能创建几乎任何大小的拉特板结构, 任意的形状和几何复杂度。 我们提出一种新的梯度方法, 优化拉特板结构的形状和填充, 以进一步提高其效率。 各自的梯度是通过充分考虑拉特板结构的变异性组合来计算的, 而拉特板表层和形状的变色问题则以顺序方式解决。 贝壳是仿制成的基尔赫霍夫- 爱普特版外观外观的外观外观, 并使用等相的亚化亚化亚表层外观外观外观的外观结构。 我们提议一种与SIMP( 以不固定的不固定的表面结构) 的变异的变形方法, 以及平面的变形技术的变形法化方法, 保证了稳定性平面的变形技术的变现过程。