“…However, the authors used the multi-scale design approach to hierarchical lattice structures and functionally graded lattice structures, respectively. Regarding composite materials, Wu et al (2020) [271] studied the robust concurrent topology optimization (CTO [42,61,138,273]) of two-phase composite materials, using an improved hybrid perturbation analysis (IHPA) method to assess the worst performance of the structure under a random model based imprecise probability. More focused on fibre reinforced materials, Yan et al (2019) [278] presented a CTO design method which optimizes the topology of the macrostructure, the material microstructure, and the material orientation.…”