Design and Characterization of Sheet-Based Gyroid Porous Structures with Bioinspired Functional Gradients

Abstract

A new type of sheet porous structures with functionally gradients based on triply periodic minimal surfaces (TPMS) is proposed for designing bone scaffolds. The graded structures were generated by constructing branched features with different number of sheets. The design of the structure was formulated mathematically and five types of porous structure with different structural features were used for investigation. The relative density (RD) and surface area to volume (SA/V) ratio of the samples were analyzed using a slice-based approach to confirm their relationships with design parameters. All samples were additively manufactured using selective laser melting (SLM), and their physical morphologies were observed and compared with the designed models. Compression tests were adopted to study the mechanical properties of the proposed structure from the obtained stress–strain curves. The results reveal that the proposed branched-sheet structures could enhance and diversify the physical and mechanical properties, indicating that it is a potential method to tune the biomechanical properties of porous scaffolds for bone tissue engineering (TE).

Terahertz Optics of Materials with Spatially Harmonically Distributed Refractive Index

“…Averaging the refractive index according to the air and material fractions it is possible to obtain its effective distribution of along the z-axis. The similar averaging procedure was performed in [ 13 ] for effective density calculations. In this case may be calculated as [ 4 ]: where is the air surface in cross-section plane perpendicular to z-axis within the unit cell , , is the refractive index of bulk material, the term is the total surface of the unit cell, .…”

“…Averaging the refractive index according to the air and material fractions it is possible to obtain its effective distribution of n e f f along the z-axis. The similar averaging procedure was performed in [13] for effective density calculations. In this case n e f f (z) may be calculated as [4]:…”

“…The gyroids are multifunctional structures–particularly in [ 13 ] they are proposed for designing bone scaffolds. The electromagnetic study of the gyroids structures of certain geometrical parameters will allow designing a new generation of components to manipulate light of different wavelength, including infrared and terahertz.…”

Mechanical and energy absorption properties of functionally graded lattice structures based on minimal curved surfaces

“…As is known to all, those conflicts which are key challenges for the enhancement of the mechanical performance of structures restricted by a series of contradictions among different properties can be easily solved in nature [1]. Inspired by the structures of wheat awn and softwood branches [2], turtle rib [3], shark denticle [4], bamboo [5] and other natural structures, many scientific research teams have been trying to find an optimal method from nature to achieve higher performance requirements [6][7][8][9]. Function graded structure (FGS) is one of the design methods derived from nature, and has been widely used in various fields, such as heat dissipating [10,11], energy absorption [12][13][14][15], optoelectronic and thermoelectric [16], biomedical prosthetic device [17][18][19][20][21] machinery and equipment application [22,23].…”

ADDITIVELY MANUFACTURED Ti6Al4V LATTICE STRUCTURES FOR BIOMEDICAL APPLICATIONS

“…TPMS topologies have porous and zero mean curvature of the surface. Their topologies are formed by some mathematical equations [6]. Some unit cell lattice structures are shown in Figure 1 (1x1x1 mm, xyz).…”