SLM lattice structures: Properties, performance, applications and challenges

Lattice structures, which are also known as architected cellular structures, have been applied in various industrial sectors, owing to their fascinated performances, such as low elastic modulus, high stiffness-to-weight ratio, low thermal expansion coefficient, and large specific surface area. The lattice structures fabricated by conventional manufacturing technologies always involve complicated process control, additional assembly steps, or other uncontrollable factors. Furthermore, limited types of unit cells can be used to construct lattice structures when using conventional processes. Fortunately, additive manufacturing technology, based on a layer-by-layer process from computer-aided design models, demonstrates the unique capability and flexibility and provides an ideal platform in manufacturing complex components like lattice structures, resulting in an effective reduction in the processing time to actual application and minimum of material waste. Therefore, additive manufacturing relieves the constraint of structure design and provides accurate fabrication for lattice structures with good quality. This work systematically presents an overview of conventional manufacturing methods and novel additive manufacturing technologies for metallic lattice structures. Afterward, the design, optimization, a variety of properties, and applications of metallic lattice structures produced by additive manufacturing are elaborated. By summarizing state-of-the-art progress of the additively manufactured metallic lattice structures, limitations and future perspectives are also discussed.

Additive manufacturing of metallic lattice structures: Unconstrained design, accurate fabrication, fascinated performances, and challenges

Manufacturability, Mechanical Properties, Mass-Transport Properties and Biocompatibility of Triply Periodic Minimal Surface (TPMS) Porous Scaffolds Fabricated by Selective Laser Melting

The development of additive manufacturing (AM) technology exhibits potential for the design and manufacturing of complex lattice structures. Herein, a novel design strategy is proposed for the lattice unit cell configurations, including triangular prism (T), quadrangular prism (Q) and hexagonal prism (H), by considering the tight spatial arrangement and manufacturing constraints. Moreover, the influence of altering the degree of freedom of nodes, caused by additional struts, on mechanical performance and energy absorption capacity is systematically investigated by theoretical modeling, experimental characterization and finite element method. A series of lattice core sandwich panels is designed and manufactured by selective laser melting (SLM). X-ray micro-computed tomography (μ-CT) is carried out to obtain the realistic geometrical information. Quasi-static uniaxial compressive tests are performed to investigate the failure mechanism and mechanical performance. The results reveal that the joint connectivity of the unit cell increased with the increase of the number of the struts, resulting in superior compressive modulus and ultimate strength. The main deformation mode of cells is gradually changed from bending-dominated to stretch-dominated with the increase of the joint connectivity. The proposed design ensures the performance consistency of the manufactured struts and facilitates the theoretical predictions and analysis. Furthermore, the specific energy absorption of the structure also increased with the increase of joint connectivity. In the case of unit cells with different configurations, T series rendered superior specific strength and specific energy absorption, whereas Q series exhibited excellent specific stiffness.

Architecture design of periodic truss-lattice cells for additive manufacturing

Lightweight materials and structures have attracted tremendous interests for their compelling advantages in a range of engineering problems that have placed heightened requirements in safety, environment, competitiveness and cost over recent years. As an effective approach, hybrid systems aim to take advantages and characteristics of different materials to maximize their functional roles in lightweight structures, thereby enhancing their respective material efficiency. This article provides a critical review on the advances in hybrid materials and structures for crashworthiness and energy absorption performance, in which fiber reinforced plastic (FRP), metals, cellular fillers and their hybrid configuration are discussed respectively. Attention is paid to the hybridization of different forms of FRP-FRP, FRP-metal, cellular filling materials with FRP structures, thereby demonstrating their constructive characteristics for different design goals. Crashworthiness and energy absorption performances of various hybridized materials, such as carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP), aluminum/steel, metallic foams/honeycombs/lattices, are evaluated and compared in detail. After highlighting the knowledge gaps in existing literatures, this review provides an outlook on the possible future research. It is expected to gain new insights into the design of novel lightweight hybrid configurations for aerospace, automotive, nautical and railway applications. • Constituent materials and preparation technology of hybrid energy absorption structures. • Experimental characterization and modeling of hybrid energy absorption structures. • Failure mechanism and parameter analysis of hybrid energy absorption structures. • Current challenges and future developments of hybrid energy absorption structures. 

Lightweight hybrid materials and structures for energy absorption: A state-of-the-art review and outlook

Evaluation of compressive properties of SLM-fabricated multi-layer lattice structures by experimental test and μ-CT-based finite element analysis

An experimental and numerical investigation of compressive response of designed Schwarz Primitive triply periodic minimal surface with non-uniform shell thickness

Mechanical properties and internal microdefects evolution of carbon fiber reinforced polymer composites: Cryogenic temperature and thermocycling effects

Carbon fiber reinforced polymer (CFRP) composites, which have excellent mechanical properties, are extensively employed under extreme service conditions such as cryogenic storage tanks. In this paper, a multi-scale model was developed to investigate the cryogenic mechanical performances of CFRP composites. An elastic-plastic damage law for epoxy resin was established based on experimental results, taking into account temperature dependencies. Microscopic models and macroscopic failure criteria were formulated to describe the cryogenic mechanical behavior, and in-situ cryogenic tests were conducted on laminates. Using this multiscale framework, the effects of the cryogenic environment on the mechanical properties and failure behaviors of CFRP composites were analyzed. According to the results, the characteristics of composites at low temperatures are embrittlement transformation and delamination damage. The predicted cryogenic properties and damage behaviors matched well with the in-situ test results. This study presents an efficient method for analyzing the structural performance and designing materials for cryogenic applications. 

Jinxin Meng

Papers

Evaluation of compressive properties of SLM-fabricated multi-layer lattice structures by experimental test and μ-CT-based finite element analysis

An experimental and numerical investigation of compressive response of designed Schwarz Primitive triply periodic minimal surface with non-uniform shell thickness

Mechanical properties and internal microdefects evolution of carbon fiber reinforced polymer composites: Cryogenic temperature and thermocycling effects

Cryogenic mechanics and damage behaviors of carbon fiber reinforced polymer composites