Programmed Plastic Deformation in Mathematically-Designed Architected Cellular Materials

Abstract

The ability to control the exhibited plastic deformation behavior of cellular materials under certain loading conditions can be harnessed to design more reliable and structurally efficient damage-tolerant materials for crashworthiness and protective equipment applications. In this work, a mathematically-based design approach is proposed to program the deformation behavior of cellular materials with minimal surface-based topologies and ductile constituent material by employing the concept of functional grading to control the local relative density of unit cells. To demonstrate the applicability of this design tactic, two examples are presented. Rhombic, and double arrow deformation profiles were programmed as the desired deformation patterns. Grayscale images were used to map the relative density distribution of the cellular material. 316L stainless steel metallic samples were fabricated using the powder bed fusion additive manufacturing technique. Results of compressive tests showed that the designed materials followed the desired programmed deformation behavior. Results of mechanical testing also showed that samples with programmed deformation exhibited higher plateau stress and toughness values as compared to their uniform counterparts while no effect on Young’s modulus was observed. Plateau stress values increased by 8.6% and 13.4% and toughness values increased by 5.6% and 11.2% for the graded-rhombic and graded-arrow patterns, respectively. Results of numerical simulations predicted the exact deformation behavior that was programmed in the samples and that were obtained experimentally.

From Brittle to Ductile: Symmetry Breaking in Strut-Based Architected Materials

“…This feature, however, poses a drawback in the case of brittle constituents: when one unit cell fails, the other unit cells will successively fail under critical compression loading, causing a sudden and catastrophic failure in the structure . This detrimental failure mode prevents early detection of failure, prompting the development of asymmetric cellular materials, which are materials consisting of heterogeneous microstructures. − …”

Recent Advancements in Design Optimization of Lattice‐Structured Materials

“…To conclude, although the dataset is very restricted and confined, functional gradation strategy seems very promising in terms of enhancing the compressive stiffness and strength of TPMS structures. Unifrom D [114] Uniform G [114] Longitudinal hybrid [114] Radial hybrid [120] Unifrom G [117] Stochastic G [117] Stochastic sheet-based [118] RDG1T [98] RDG1T [98] RDG2 [98] RDG3 [98] CSG1 [98] CSG2 [98] CSG2T [98] CSG3 [98] Uniform Sheet G [100] Graded G [100] Graded Rhombic [101] Unifrom P [101] Graded Arrows [101] Unifrom P [101] ρ Unifrom G [117] Stochastic G [117] RDG2 [98] RDG3 [98] CSG1 [98] CSG2 [98] CSG2T [98] CSG3 [98] Uniform Sheet G [100] Graded G [100] Graded Rhombic [101] Unifrom P [101] Graded Arrows [101] Unifrom P […”

“…Almesmari et al [128] reported that for mesoscale structures, the geometrical deviation between the as-built and as-designed lattices increased as their aspect ratio (i.e., ratio of cell wall thickness to unit cell size) approached the minimum resolution of an FDM printer. Jiang and Ning [129] utilized the printing-debinding-sintering Unifrom D [114] Uniform G [114] Longitudinal hybrid [114] Radial hybrid [120] Unifrom G [117] Stochastic G [117] Stochastic sheet-based [118] RDG1T [98] RDG2 [98] RDG3 [98] CSG1 [98] CSG2 [98] CSG2T [98] CSG3 [98] Uniform Sheet G [100] Graded G [100] Graded Rhombic [101] Unifrom P [101] Graded Arrows (PDS) process to fabricate BCC, FCC, and BCC-FCC plate lattices made of 17-4 stainless steel in a multistep procedure consisting of FDM printing of metal-polymer composites, debinding the printed pats (i.e., green parts) to remove polymeric wax and then sintering the components in a furnace to improve the layers binding strength. Utilization of the PDS process seems very promising to enhance the printing accuracy of the conventional FDM technology.…”

“…Additionally, Oladapo et al [183] designed and tested polymer composite-based gyroid and BCCO scaffolds as dental implants (Figure 15d). The results revealed that these structures possess similar elastic and shear moduli as compared Stochastic G [117] RDG2 [98] RDG3 [98] CSG1 [98] CSG2 [98] CSG2T [98] CSG3 [98] Graded G [100] Graded Rhombic [101] Graded Arrows [101] G (size gradation) [99] D (size gradation) [99] Hybrid [99] Gyroid [99] Lattice A [169] Lattice B…”

A Classification of Aperiodic Architected Cellular Materials

“…In Figure 3, the feature being graded is the width of the rectangular unit cell, which increases from left to right. In addition to modulating cell size, it is also possible to spatially prescribe variations in wall thickness, even with discrete step changes in value, as shown in one example from the published literature in Figure 4a [19]. With advances in simulation capabilities, particularly with topology optimization, it is possible to prescribe these gradients in response to a field derived from simulation [20,21].…”