Light-weight/defect-tolerant topologically self-interlocking polymeric structure by fused deposition modeling

Open-cell structures such as self-interlocking (SIL) assemblies show advantages in weight reduction, insulation, energy dissipation, and impact energy absorption. However, there are few studies investigating the tensile property and energy absorption performance of SIL structures. Here, topological SIL polymeric structures were 3D printed by fused deposition modeling with constant and proportional strut thickness, to study the scaling laws relating strength and toughness of the structure to its dimensions. Relative density (rho) over bar changes from 0.03 to 0.31 with the number of tetrahedron elements in X/Y directions for structures which have constant strut thickness; but the (rho) over bar is fixed at 0.13 regarding the number of tetrahedron elements changes for those with proportional strut thickness. According to tensile and in-plane/out-of-plane compression tests, as well as FEA analysis, there is a clear relative density dependence in the defect-tolerant structure performance. The maximum tensile stresses for samples C-77 ((rho) over bar = 0.31) and P-77 ((rho) over bar = 0.13) are 4.68 MPa and 1.15 MPa, respectively. And the absorbed kinetic energy is about 2.7 J/cm(3) for sample C-77 but 0.6 J/cm(3) for sample P-77. It is envisioned that such structure can be reinforced within a host for impact mitigation and damage-induced crack on-demand healing for future endeavors.