Plasticity in polymeric honeycombs made by photo-polymerization and nozzle based 3D-printing

Study of the plastic deformation in polymeric honeycombs can pave the way for understanding the deformation localization in more complex cellular structures, which have received progressive attention in the past few years. This study compares the strain localization in deforming honeycombs made by two cost-effective 3D-printing technologies. Hexagonal honeycombs and their unit cell models were 3D-printed by both PolyJet™, using a photo-crosslinkable polymer, and fused deposition modeling (FDM) using a thermoplastic material. The state of the art digital image correlation (DIC) technique was employed as the experimental route in order to calculate the strain field during the deformation of manufactured parts. It was found that DIC is an effective tool to study the localization in 3D-printed honeycomb struts. Moreover, in comparison with FDM, PolyJet technology provides more homogeneous strain distributions in struts. In addition, FDM decreases the maximal strains generated on the side layers of the honeycomb struts. Accordingly, the ligament damage under plastic deformation can be postponed and the energy absorption capability of the product can be improved when PolyJet technology is utilized.