Multiscale optimization of additively manufactured graded non-stochastic and stochastic lattice structures

Lattice structures are increasingly used in practical engineering due to their excellent mechanical properties such as light weight, high load-bearing capacity, and high ductility. In this work, a multiscale optimization framework is developed for optimizing the graded non-stochastic (box-shaped and X-shaped) and stochastic (triangle-shaped and Voronoi-shaped) lattice structures. Three main parts are included in this approach: the modeling and analysis of the microstructure, the optimization of relative density on the macroscopic scale, and the reconstruction of the full-scale graded lattice structure. Each part is introduced and discussed in detail in this work. The size effects of the optimized lattice structures are studied based on the full-scale finite element analysis. In addition, the defect sensitivities of the traditional single-scale structures and the lattice structures are also investigated. Furthermore, the experimental tests and numerical simulations are carried out for examining the advantages and disadvantages of the lattice structures optimized by the proposed method, by comparing with the single-scale structures optimized by the traditional parameterized level set method. •An optimization framework is developed for designing graded lattice structures.•The graded lattice structures have good load-bearing capacity and ductility.•Both the experimental tests and the nonlinear simulations are conducted.•The elastic tensor of stochastic microstructure is mapped to an isotropic one.