Evaluating Lattice Mechanical Properties for Lightweight Heat-Resistant Load-Bearing Structure Design

Abstract

Heat-resistant, load-bearing components are common in aircraft, and they have high requirements for lightweight and mechanical performance. Lattice topology optimization can achieve high mechanical properties and obtain lightweight designs. Appropriate lattice selection is crucial when employing the lattice topology optimization method. The mechanical properties of a structure can be optimized by choosing lattice structures suitable for the specific stress environment being endured by the structural components. Metal lattice structures exhibit excellent unidirectional load-bearing performance and the triply periodic minimal surface (TPMS) porous structure can satisfy multi-scale free designs. Both lattice types can provide unique advantages; therefore, we designed three types of metal lattices (body-centered cubic (BCC), BCC with Z-struts (BCCZ), and honeycomb) and three types of TPMS lattices (gyroid, primitive, and I-Wrapped Package (I-WP)) combined with the solid shell. Each was designed with high level of relative density (40%, 50%, 60%, 70%, and 80%), which can be directly used in engineering practice. All test specimens were manufactured by selective laser melting (SLM) technology using Inconel 718 superalloy as the material and underwent static tensile testing. We found that the honeycomb test specimen exhibits the best strength, toughness, and stiffness properties among all structures evaluated, which is especially suitable for the lattice topology optimization design of heat-resistant, unidirectional load-bearing structures within aircraft. Furthermore, we also found an interesting phenomenon that the toughness of the primitive and honeycomb porous test specimens exhibited sudden increases from 70% to 80% and from 50% to 60% relative density, respectively, due to their structural characteristics. According to the range of the exponent value n and the deformation laws of porous structures, we also concluded that a porous structure would exhibit a stretching-dominated deformation behavior when exponent value n < 0.3, a bending-dominated deformation behavior when n > 0.55, and a stretching-bending-dominated deformation behavior when 0.3 < n < 0.55. This study can provide a design basis for selecting an appropriate lattice in lattice topology optimization design.

The Thermal Properties of a Prototype Insulation with a Gyroid Structure—Optimization of the Structure of a Cellular Composite Made Using SLS Printing Technology

“…3D printing technology is still relatively young and has many limitations, but the expectations and hopes for the future of 3D-printed buildings and building elements are high. Research concerning the versatile applications of 3D printers and the development of new filamentous materials that could provide various properties ensuring transparency, thermal insulation, or strength are being conducted [17][18][19]. Layered composites, considered as special materials, are widely used in the aviation, marine, automotive, and construction industries, and thanks to 3D printing technology they acquire a new meaning.…”

“…Layered composites, considered as special materials, are widely used in the aviation, marine, automotive, and construction industries, and thanks to 3D printing technology they acquire a new meaning. Composites with the so-called sandwich structure [18], which have a low-density core and rigid layers that are arranged on the outside of the composites, are very often used. The core can be made in the form of closed, or open foam or periodic, structures [18].…”

“…Composites with the so-called sandwich structure [18], which have a low-density core and rigid layers that are arranged on the outside of the composites, are very often used. The core can be made in the form of closed, or open foam or periodic, structures [18]. Layered materials can be divided into four types: cellular foam, honeycomb, corrugated cardboard, and balsa [18].…”

A Numerical Study of Geometry’s Impact on the Thermal and Mechanical Properties of Periodic Surface Structures

“…The finite element simulation results also showed that diamond and gyroid structures exhibit relatively uniform stress distributions in all grid cells subjected to compression, leading to stable collapse mechanisms and the desired energy absorption efficiency. In [ 19 ], the cubic periodic structure of various designs was simulated under quasi-static compression. For numerical tests and experimental verification, the authors used specimens fabricated by selective laser melting.…”

Investigation on Morphology and Mechanical Properties of Rod Units in Lattice Structures Fabricated by Selective Laser Melting

“…In a wide variety of engineering applications, such as in the aerospace, military, automotive, and medical industries, the weight of parts has significant impacts on both functional performance and usage cost [ 1 , 2 , 3 , 4 ]. As a typical light weight structure, lattice structures continue to receive considerable interest, as they not only provide good mechanical properties (such as exceptional load bearing efficiency and customizable stiffness), but also possess some intriguing functionalities such as energy absorption, acoustic and elastic wave manipulation, etc.…”