Strain Rate and Structure Dependent Behavior of Lattice Structures of a Titanium Alloy Fabricated by Selective Laser Melting

Because of their prominent mechanical properties, lattice materials have shown great potential in a wide variety of engineering applications related to energy absorption, including blast and impact protection system, thermal insulation, and vehicle components. However, the design of lattice materials under dynamic loading has been rarely studied. This work focused on the strain rate and structure dependent behavior of the lattice materials based on two simple representative architectures: a bending-dominated body-centered cubic structure (BCC) and a stretching-dominated face-centered cubic structure (FCC). Both simulations and experiments were conducted to study their compressive behaviors under quasi-static and dynamic loading. The results show that the mechanical behavior of FCC is less sensitive to the number of layers than that of BCC. As the loading rate increases, the deformation behavior of the lattice structures changes from uniform compression to local deformation concentrated at the impact end. In addition, the critical impact transition velocities of the uniform deformation mode, transition mode and impact deformation mode of BCC and FCC with different number of layers were determined.