Figure 3.

(a) Thermal properties of the Octet bi-materials and benchmark concepts (S-concept⁹ and H-concept³²) plotted with respect to the normalized skew angle, θ_Normalized. Shown in bracket below each pictorial, θ_Normalized is calculated as θ_Normalized = (θ_Model − θ_min)/(θ_max − θ_min), where θ_Model is the skew angle of a concept, and θ_min and θ_max are respectively the minimum and maximum skew angle that a concept can provide without its cell topology degenerates. (b) Histogram showing the CTE tunability (∆CTE) as well as the max and min CTE for the selected concepts compared to a low CTE solid material, i.e. Ti-6Al-4V. (c) Effective stiffness and (d) effective strength plotted with respect to relative density ρ*. Note ρ* = ρ_lattice/ρ_{solid composite} where ρ_lattice is the actual density of the bi-material unit cell and ρ_{solid composite} is the density of the solid bi-material with volume fraction of the constituent materials. Note that the maximum relative density of the Iso-CTE Octet does not reach 0.3; it is 0.2 for θ_I = 50°, and 0.25 for θ_I = 60°, because above these values the size of the joints become unfeasibly larger than the cell members, which means that the cell is unfeasible.