Quasi-Static Compression and Deformation Behavior of Additively Manufactured Flexible Polymeric Lattice Structure

The influence of unit cell configuration and relative density on compression behavior, deformation mechanism and energy absorption capacity of body centered cubic (BCC) flexible polymeric lattice structures was experimentally investigated in this work. Three different types of BCC cell configurations i.e. uniform cell (UBCC), uniform with z-axis reinforced cell (UBCCz) and graded cell (GBCC) were additively manufactured through digital light processing 3D printing process. Quasi static compressive testing was carried out to determine the mechanical response of lattice structures and significant effect of cell architecture and relative density on compression and strength properties were observed. The experimental results show that irrespective of lattice type the elastic modulus and collapse strength of each lattice increases with increasing relative density. However, the modulus and strength for UBCCz is higher than other two configurations due to additional vertical strut which add extra stiffening in loading direction. UBCCz lattice also showed high energy absorption capacity followed by UBCC and GBCC lattice. It was also determined that for any fixed relative density, different lattice configurations show different stress-strain behavior and deformation modes due to unique unit cell construction. The non-graded lattice shows a uniform overall deformation while gradient lattice shows layer by layer collapse. The work proposed that lattice relative density and cell configuration can be steered to improve the overall stiffness and strength of flexible lattice structures in energy absorption applications.