Parametric Study on the Performance of Cast Lattice Structures Loaded at Low Strain-Rates

Designing lightweight structures for maximum energy absorption is a challenging endeavor. These structures have applications in everyday life, including low-velocity impacts, shielding helmets for bicycle riders, and small tools accidentally falling on aircraft and automobiles. Periodic strut-based lattice structures can be easily fabricated using additive manufacturing (AM) owing to the high degree of freedom of design that it affords. A hybrid approach that combines the inherent benefits of AM with metalcasting is used to manufacture lattice structures in aluminum A356 and F356 alloys. In this paper, the performances of these structures are experimentally evaluated by applying uniaxial compressive loads at a low strain rate. LS-DYNA software is used to generate a finite element model to study highly non-linear deformations. This model is then used to computationally evaluate other truss arrangements, and a pathway for optimizing the octet-truss is proposed. In terms of the specific internal energy, the optimized structure in A356 outperforms the standard design by approximately 30%.