3D-Printed Collision Energy Absorber via Graded Stacking of Hard and Soft Material Layers

An energy absorber exhibiting progressive failure and efficient energy absorption, named dual-material energy absorbers (DME), was developed via a graded stacking of hard and soft material layers. Polyamide 6 (PA6) and elastomer-modified PA6 were, respectively, used as hard and soft materials to prevent delamination between the hard and soft material layers. The filaments for an FDM-type 3D printer were fabricated by using a twin extruder. DMEs were fabricated by alternately extruding hard and soft materials by using a FDM-type 3D printer with two nozzles. The interface between the hard and soft materials in the DME exhibited good adhesion, owing to the miscibility of the PA6 molecular chain in both materials. Static compression testing revealed that the DME exhibited progressive deformation, and the absorption energy of the DME was twice as high energy as those of monomaterial structures. The deformation behavior under impact loading was confirmed via a drop-weight impact test.