Ultralight Metallic/Composite Materials
25
3 Ultralight Architected Cellular Metallic/Composite Materials
3.1 Metallic Octahedral Micro-architecture
Metallic cellular materials fabricated at HRL Laboratories [2, 3] are nickel-based materials with octahedral configuration without any basal members. Micro-architected metals
consist of hollow tube strut members with the length of L = 1 − 4 mm, the strut
diameter of D = 100 − 500 µm, the wall thickness of t = 100 − 500 nm, and the
inclination angle of θ = 60
◦ . Using the RVE approach in conjunction with plastic hinge
method, we model a nickel-based cellular material with L = 1200 µm, D = 175 µm,
and t = 26 µm and compare the calculated mechanical results with the corresponding
experimental measurements. For this study, an RVE consisting of 36 nodes and 64 strut
members is considered under compressive loading, Fig. 2(a). The structural geometry
of the strut member is also shown in Fig. 2(b).
(a)
a
a
4a
x
y
z
(b)
Fig. 2. (a) An RVE consisting of 36 nodes and 64 strut members and (b) the structural geometry
of the strut member.
Using the present methodology, the engineering stress-engineering strain curve is
calculated and plotted in Fig. 3. The Young’s modulus and the yield stress are calculated
as 0.7841 GPa and 7.3704 MPa, respectively. The experimental measurements reported
by Torrents et al. [3] for the tested micro-lattice with the strut diameter D = 175 ±
26 µm, strut length L = 1200 ± 36 µm, and wall thickness t = 26.00 ± 2.6 µm exhibit
25
3 Ultralight Architected Cellular Metallic/Composite Materials
3.1 Metallic Octahedral Micro-architecture
Metallic cellular materials fabricated at HRL Laboratories [2, 3] are nickel-based materials with octahedral configuration without any basal members. Micro-architected metals
consist of hollow tube strut members with the length of L = 1 − 4 mm, the strut
diameter of D = 100 − 500 µm, the wall thickness of t = 100 − 500 nm, and the
inclination angle of θ = 60
◦ . Using the RVE approach in conjunction with plastic hinge
method, we model a nickel-based cellular material with L = 1200 µm, D = 175 µm,
and t = 26 µm and compare the calculated mechanical results with the corresponding
experimental measurements. For this study, an RVE consisting of 36 nodes and 64 strut
members is considered under compressive loading, Fig. 2(a). The structural geometry
of the strut member is also shown in Fig. 2(b).
(a)
a
a
4a
x
y
z
(b)
Fig. 2. (a) An RVE consisting of 36 nodes and 64 strut members and (b) the structural geometry
of the strut member.
Using the present methodology, the engineering stress-engineering strain curve is
calculated and plotted in Fig. 3. The Young’s modulus and the yield stress are calculated
as 0.7841 GPa and 7.3704 MPa, respectively. The experimental measurements reported
by Torrents et al. [3] for the tested micro-lattice with the strut diameter D = 175 ±
26 µm, strut length L = 1200 ± 36 µm, and wall thickness t = 26.00 ± 2.6 µm exhibit