SHAPE AND SIZE OPTIMIZATION OF ADDITIVE MANUFACTURED LATTICE CORES WITH AN EVOLUTIONARY-BASED APPROACH FOR HIGH-PERFORMANCE SANDWICH PANELS

The evolution of additive manufacturing techniques has vastly increased the design space of lattice structures, making it possible to create stiffer and lighter ones. This work deals with the evolutionary shape and size optimization of lattice structures, using a genetic algorithm (GA). A modelling framework involving finite element (FE) homogenization of representative volume elements (RVE) under strain-controlled Periodic Boundary Conditions (PBCs) is employed. Several designs of lattice structures were optimized with this approach. These designs were obtained superimposing basic lattice unit cells, such as body-centred cubic (BCC), face-centred cubic (FCC), simple cubic (SC) and octahedral, considering additive manufacturing constraints. The optimization objective was the maximisation of the specific compressive stiffness of the lattices, limiting the maximum relative density to 0.30. The optimized led to a five-fold increase of the specific compressive stiffness.