Chapter 7 - Plate lattice metamaterials

Abstract

Plate lattices are an emerging class of lightweight mechanical metamaterials that exhibit superior mechanical properties. The unique architectures of plate lattice metamaterials are regarded as the origin of achieving such advanced performance, but they lead to the difficulty of powder removal after the powder-bed-based additive manufacturing process. In this chapter, plate lattice metamaterials with half-open-cell topology are proposed and fabricated via the laser powder bed fusion technique. To investigate their mechanical performance and deformation behaviors, numerical simulations and experimental tests are performed on finite element models and as-built specimens, respectively. Simulation results show that the mechanical properties and elastic anisotropy of half-open-cell plate lattice metamaterials are easily tunable when changing the geometric parameters, e.g., plate thickness or hole diameter. The elastic moduli and Poisson's ratio are found to scale nonlinearly with the hole diameter for different plate thicknesses, and the elastic anisotropy approaches 1.0 for specific hole size. The specific energy absorption of half-open-cell plate lattice metamaterials is up to two times higher than that of truss lattice metamaterials. The porous architecture, lightweight body, and superior and easily tunable mechanical performance of half-open-cell plate lattice metamaterials give them application potential in the fields of load-bearing, energy absorption, and biomedical engineering. In bone scaffolds, mechanical performance provides the load-bearing capability, and mass-transport performance presented as permeability dominates the nutrients/oxygen transportation efficiency. Body-centered-cubic and face-centered-cubic plate lattice scaffolds with mechanical and mass-transport performance similar to that of human bones are proposed in the present study. The regular periodic architecture and plane-stress state of the plate lattice scaffolds not only provide them with advanced mechanical properties but avoid stress concentration that ubiquitously exists in traditional truss lattice scaffolds. By investigating the anisotropic mechanical and mass-transport performance of plate lattice scaffolds, a valid regulation strategy is put forward to modulate their performance without changing the volume fraction and architecture, providing an alternative scheme for biomedical scaffold design. Both computational and experimental results demonstrate that body-centered-cubic and face-centered-cubic plate lattice scaffolds possess appropriate mechanical and mass-transport performance similar to that of human bones. In addition, tuning ranges of the mechanical and mass-transport performance of plate lattice scaffolds for different orientations are up to 40% and 45%, respectively. These findings could provide valuable references for the extensive applications of plate lattice scaffolds in bone tissue engineering.