Fig. 4. FE simulations and DIC analysis.

(A and B) Von Mises stress distributions just before the onset of fracture in octet truss and Schwarz P shell lattices with a similar relative density of ~21% from FE simulations (with beam and shell elements). The von Mises stress is normalized by the yield stress of the constituent material. (C and D) Equivalent plastic strain distributions in octet truss and Schwarz P shell lattices with a similar relative density of ~21% from FE simulations (with beam and shell elements). The equivalent plastic strain is normalized by the plastic strain of the constituent material at damage initiation. (E and F) DIC maps at the moment of fracture initiation and at a later stage of crack propagation in octet truss and Schwarz P shell lattices with relative density of 17.2 and 17.3%, respectively. Scale bars, 5 mm. FE simulations and DIC analysis demonstrate larger plastic zone and fracture process zone sizes in the Schwarz P shell lattice. (G) Schematic of fracture mechanisms in lattice materials. (H and I) Fracture energy decoupling from FE simulations using brittle and ductile material behaviors, respectively (with solid elements).