Mechanical behavior of polymeric selective laser sintered ligament and sheet based lattices of triply periodic minimal surface architectures

Advances in additive manufacturing triggered a paradigm shift in the design of functional components allowing for complex topology-driven cellular lattices to be incorporated for the aim of reducing weight, enhancing multi-functionality, and facilitating manufacturability. In this paper, the compressive mechanical behavior of different polymeric lattices based on triply periodic minimal surfaces (TPMS) are investigated both experimentally and computationally. The behavior of two classes of TPMS lattices are investigated; sheet- and ligament-based lattices. Samples are fabricated using the laser powder bed fusion technique, selective laser sintering, and characterized using micro-Computed Tomography (micro-CT) and Scanning Electron Microscopy (SEM). A finite-deformation hyperelastic-viscoplastic-damage constitutive model is calibrated and employed to capture the full compressive behavior of lattices. The computational results are compared to and validated against corresponding experimental results. Results show that sheet-based polymeric TPMS lattices exhibit a stretching-dominated mode of deformation and prove to have superior stiffness and strength as compared to TPMS ligament-based lattices. The numerical simulations are in good agreement with experimental results for ligament-based lattices while significant deviation from experimental results is observed for the sheet-based lattices which is attributed to uncertainty in measuring the actual relative density and relatively higher manufacturing defects.