Mechanical performance of a new isotropic closed-cell Ti-6Al-4V plate-lattice material: Finite element and analytical assessment

The pursuit of lightweight mechanical metamaterials with elastic isotropy, high specific stiffness and strength has long been a core challenge in advanced engineering. Among emerging architectures, plate-lattice structures exhibit unique potential to approach the theoretical performance limits of isotropic porous solids. This work presents an original isotropic closed-cell Ti-6Al-4V plate-lattice with SC-irFCC (simple-cubic & internally-reinforced face-centered-cubic) symmetry. Its mechanical performance is systematically investigated using continuum homogenization, implicit finite-element simulations based on representative volume elements (RVEs) under periodic displacement boundary conditions, and large-deformation explicit simulations of multi-cell lattices. Key properties including directional elastic moduli, uniaxial yield strength, failure mechanisms, and crushing response are quantified over a wide range of relative densities. The SC-irFCC plate-lattice demonstrates exceptional elastic isotropy and favorable plastic isotropy, with effective stiffness and strength approaching the Hashin–Shtrikman and Suquet upper bounds for isotropic porous media, respectively. The threshold for buckling–yielding failure mode transition is identified at a relative density of approximately 0.18. Under large-deformation compression, multi-cell lattices exhibit nearly orientation-independent specific energy absorption performance. The Gibson–Ashby scaling relations are established for stiffness, yield strength, and specific energy absorption. Ashby chart benchmarking confirms that Ti-6Al-4V SC-irFCC plate-lattice outperforms numerous conventional cellular solids, rendering it highly competitive for lightweight, load-bearing applications requiring orientation-insensitive mechanical response.