Design Optimization of Lattice Structures under Compression: Study of Unit Cell Types and Cell Arrangements

Abstract

Additive manufacturing enables innovative structural design for industrial applications, which allows the fabrication of lattice structures with enhanced mechanical properties, including a high strength-to-relative-density ratio. However, to commercialize lattice structures, it is necessary to define the designability of lattice geometries and characterize the associated mechanical responses, including the compressive strength. The objective of this study was to provide an optimized design process for lattice structures and develop a lattice structure characterization database that can be used to differentiate unit cell topologies and guide the unit cell selection for compression-dominated structures. Linear static finite element analysis (FEA), nonlinear FEA, and experimental tests were performed on 11 types of unit cell-based lattice structures with dimensions of 20 mm × 20 mm × 20 mm. Consequently, under the same relative density conditions, simple cubic, octahedron, truncated cube, and truncated octahedron-based lattice structures with a 3 × 3 × 3 array pattern showed the best axial compressive strength properties. Correlations among the unit cell types, lattice structure topologies, relative densities, unit cell array patterns, and mechanical properties were identified, indicating their influence in describing and predicting the behaviors of lattice structures.

The Energy Absorption Behavior of 3D-Printed Polymeric Octet-Truss Lattice Structures of Varying Strut Length and Radius

“…In contrast with conventional foam/honeycomb cellular metamaterials, energy absorbing lattice structures present a compelling alternative in applications demanding low weight and relatively high stiffness [ 1 , 2 , 3 , 4 ]. The applications of such materials vary greatly, from packaging, structural, automotive (panels, energy absorbers, armor), acoustic, and personal protective equipment (PPE) such as sporting helmets [ 3 , 4 , 5 , 6 , 7 , 8 ], but not medical PPE such as face masks/shields [ 9 ]. Another important application of 3D-printed cellular structures includes tissue engineering scaffolds within the medical field [ 10 , 11 , 12 ].…”

“…These structures are alternatives to existing cellular materials, which include aluminum honeycombs/foams [ 20 , 25 , 26 ] and conventional expanded polystyrene foams [ 26 , 27 , 28 , 29 , 30 ]. Unlike the stochastic unit cell structure of cellular materials, the regularity of the lattice unit cell allows one to control the overall structure performance and tune/optimize the lattice geometry to create a functionally graded material for individual design applications [ 8 , 14 , 17 , 23 , 26 ]. Several different unit cell geometries exist and have been examined in the literature [ 8 , 18 , 31 , 32 ].…”

“…Unlike the stochastic unit cell structure of cellular materials, the regularity of the lattice unit cell allows one to control the overall structure performance and tune/optimize the lattice geometry to create a functionally graded material for individual design applications [ 8 , 14 , 17 , 23 , 26 ]. Several different unit cell geometries exist and have been examined in the literature [ 8 , 18 , 31 , 32 ]. This work focuses on the octet-truss unit cell, which is configured in a face-centered cubic (FCC) arrangement [ 33 ].…”

Design and analysis of strut-based lattice structure cranial implant

“…These structures can be classified in a variety of ways. They are divided into two categories based on their topologies: stochastic (unsystematic distribution) and periodic (systematic distribution) [15]. They can also be divided into groups based on the structures that are dominated by stretching and bending.…”

“…In these structures, porosity and relative density are inversely correlated, and stiffness has a direct relationship with both. Lattice structures have superior mechanical properties than honeycomb and foam type of structures [15,17].…”