Properties Evaluations of Topology Optimized Functionally Graded Lattice Structures Fabricated by Selective Laser Melting

Abstract

Owning to their lightweight characteristic and high performance, functionally graded lattice structures (FGLSs) show great potential in orthopedics, automotive industries and aerospace applications. Here, two types of uniform lattice structures (ULSs) with RD = 0.50 and 0.20, and two types of FGLSs with RD = 0.30–0.50 and RD = 0.20–0.40, were designed by topology optimization and fabricated by SLM technology. Subsequently, their surface morphology, compressive deformation behavior and energy absorption abilities were evaluated by use of the finite element method (FEM) and compression tests. From these results, both elastic modulus and yield strength of specimens decreased with the lowering of the RD value. ULSs had a uniform deformation behavior with bending and bulking of struts, while FGLSs presented a mixed deformation behavior of different layers. Additionally, the energy absorption capability (Wv) of specimens was proportional to the RD value. When the value of RD increased from 0.20 to 0.50, the Wv of specimens increased from 0.3657 to 1.7469 MJ/m3. Furthermore, mathematical models were established successfully to predict the mechanical properties of FGLSs with percentage deviations < 10%. This work provides a comprehensive understanding regarding how to design and manufacture FGLSs with the properties desired for satisfying the demand of different application scenarios.

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

“…For example, functionally graded porous (FGP) constructs have been designed to match the heterogenous structural or mechanical properties of different locations within bone [ 3 , 13 ]. Porosity gradient FGP designs attempt to match variation in the natural structure of bone [ 143 , 144 , 145 ]. In topology-optimized FGP designs, the density of the lattice structure is set to match spatial variation in the mechanical properties of bone [ 143 , 146 ].…”

“…Porosity gradient FGP designs attempt to match variation in the natural structure of bone [ 143 , 144 , 145 ]. In topology-optimized FGP designs, the density of the lattice structure is set to match spatial variation in the mechanical properties of bone [ 143 , 146 ]. In both cases, the gradient within FGP designs is ideally continuous to simulate the complex features of bone structure and its mechanical properties [ 147 ].…”

The Influence of Heat Treatment Temperature on Tensile Properties of Metal-Bonded Diamond Composites Fabricated via Selective Laser Melting

“…The red color represents the high temperature region while the blue color is the low temperature region. An ideal SLM fabricating process should show a consistent temperature field [26]. However, some red and yellow regions appeared in the melt pool monitor data, indicating a large thermal stress existing in the specimens.…”

Structural Performance of Additively Manufactured Composite Lattice Structures: Strain Rate, Cell Geometry, and Weight Ratio Effects

“…[40,41] Lattice structures have been printed with a broad range of engineering materials using various additive manufacturing techniques, including fused filament fabrication, [42,43] material jetting, [40,44] vat photopolymerization, [22] and selective laser sintering. [45][46][47] These additively manufactured ordered lattice structures strategically (i.e., through intentional design and formal optimization) fill several gaps in property maps, [48][49][50] including stiffness, [51,52] strength, [53] specific energy absorption (SEA), [54] and toughness. [55] Furthermore, additive manufacturing technologies accelerated the development of discrete or continuous density and functionally graded materials, achieving architected metastructures with novel behaviors such as negative Poisson's ratio, [5,56] negative coefficient of thermal expansion, [57] or negative refractive index.…”