A numerical investigation of the deformation behaviour of modified re-entrant lattice structure unit cells

The design optimisation of lattice metamaterial unit cells for enhanced properties has been a central theme in current studies. This study contributes to this cause through the development of modified re-entrant structure geometries. Through geometric tailoring and hybridisation of the conventional re-entrant lattice structure, three novel geometries have been developed, and their respective mechanical properties and deformation behaviour under in-plane compressive loading have been investigated using numerical modelling through the finite element analysis technique. Model 3, which comprised a centrally placed auxetic star shape fused onto the re-entrant structure, demonstrated higher stiffness and greater energy absorption properties. Model 1, which comprised a cellular arranged star with double arrow-head auxetic structures around the walls of the re-entrant geometry, demonstrated a lower stiffness with unique elasticity. Model 2, which consisted of an integrated rib comprising different auxetic geometries, demonstrated functionally graded deformation behaviour suitable for tailored mechanical properties. Models 1 and 3 displayed unique properties as a result of the resulting load paths and deformation models associated with each geometric configuration. The findings offer valuable insights for guiding future research aimed at optimising re-entrant lattice structures for tailored mechanical properties. The demonstrated improvements provide a strong foundation for exploring additional design variations.