Lattice-skin structures design with orientation optimization

Parts with complex geometry can be produced by an additive manufacturing process without a significant increase of fabrication time and cost. One application of AM technologies is to fabricate customized lattice structures to enhance products' performance with less material and less weight. Thus, design methods of customized lattice structures have recently attracted great research interests. Most existing design methods only consider the distribution of lattice struts' thickness as a primary design variable for customized lattice structures. Few of them notice the importance of lattice orientation with regard to its structural performance. In this paper, a design method for customized lattice-skin structures is proposed to optimize the distribution of lattice orientations inside the design domain. In this design method, an initial Functional Volume (FV) is divided into several sub-FVs and connected with additional Functional Surfaces (FSs). The orientation of uniform lattice in each sub-FV is regarded as the design variable. To optimize the design variables, an equivalent analysis model based on the effective orthotropic properties of lattice structures is built. On the basis of this model, genetic algorithm is applied to obtain the optimized distribution of lattice orientations. Two case studies are provided at the end of this paper to validate the proposed design method.