scholarly journals Design and Optimization of Lattice Structures: A Review

2020 ◽  
Vol 10 (18) ◽  
pp. 6374
Author(s):  
Chen Pan ◽  
Yafeng Han ◽  
Jiping Lu

Cellular structures consist of foams, honeycombs, and lattices. Lattices have many outstanding properties over foams and honeycombs, such as lightweight, high strength, absorbing energy, and reducing vibration, which has been extensively studied and concerned. Because of excellent properties, lattice structures have been widely used in aviation, bio-engineering, automation, and other industrial fields. In particular, the application of additive manufacturing (AM) technology used for fabricating lattice structures has pushed the development of designing lattice structures to a new stage and made a breakthrough progress. By searching a large number of research literature, the primary work of this paper reviews the lattice structures. First, based on the introductions about lattices of literature, the definition and classification of lattice structures are concluded. Lattice structures are divided into two general categories in this paper: uniform and non-uniform. Second, the performance and application of lattice structures are introduced in detail. In addition, the fabricating methods of lattice structures, i.e., traditional processing and additive manufacturing, are evaluated. Third, for uniform lattice structures, the main concern during design is to develop highly functional unit cells, which in this paper is summarized as three different methods, i.e., geometric unit cell based, mathematical algorithm generated, and topology optimization. Forth, non-uniform lattice structures are reviewed from two aspects of gradient and topology optimization. These methods include Voronoi-tessellation, size gradient method (SGM), size matching and scaling (SMS), and homogenization, optimization, and construction (HOC). Finally, the future development of lattice structures is prospected from different aspects.

Author(s):  
Boštjan Harl ◽  
Jožef Predan ◽  
Marko Kegl ◽  
Dejan Dinevski

This paper discusses modern simulation procedures used in design of structural load-carrying parts that are based on the Finite Element Method. The specific focus of the paper is the topology optimization usage within the context of two currently very interesting topics: configuration and optimization of lattice structures and modern additive manufacturing technologies. Both types of structures are presented together with their limits as well as their potentials for optimization. The discussion is illustrated by two numerical examples and experimentally obtained results. In the examples, a simple beam with three points load is optimized regarding to the different topology setups. The stress fields for different loaded optimized versions of structures are presented and the solutions are discussed and compared to the results of the experiment. A standalone topology optimization software CAESS ProTOp is used for the domain configuration and topology optimization in both examples.


Author(s):  
Bradley Hanks ◽  
Mary Frecker

Abstract Additive manufacturing is a developing technology that enhances design freedom at multiple length scales, from the macroscale, or bulk geometry, to the mesoscale, such as lattice structures, and even down to tailored microstructure. At the mesoscale, lattice structures are often used to replace solid sections of material and are typically patterned after generic topologies. The mechanical properties and performance of generic unit cell topologies are being explored by many researchers but there is a lack of development of custom lattice structures, optimized for their application, with considerations for design for additive manufacturing. This work proposes a ground structure topology optimization method for systematic unit cell optimization. Two case studies are presented to demonstrate the approach. Case Study 1 results in a range of unit cell designs that transition from maximum thermal conductivity to minimization of compliance. Case Study 2 shows the opportunity for constitutive matching of the bulk lattice properties to a target constitutive matrix. Future work will include validation of unit cell modeling, testing of optimized solutions, and further development of the approach through expansion to 3D and refinement of objective, penalty, and constraint functions.


2021 ◽  
Author(s):  
Niclas Strömberg

Abstract The use of lattice structures in design for additive manufacturing has quickly emerged as a popular and efficient design alternative for creating innovative multifunctional lightweight solutions. In particular, the family of triply periodic minimal surfaces (TPMS) studied in detail by Schoen for generating frame-or shell-based lattice structures seems extra promising. In this paper a multi-scale topology optimization approach for optimal macro-layout and local grading of TPMS-based lattice structures is presented. The approach is formulated using two different density fields, one for identifying the macro-layout and another one for setting the local grading of the TPMS-based lattice. The macro density variable is governed by the standard SIMP formulation, but the local one defines the orthotropic elasticity of the element following material interpolation laws derived by numerical homogenization. Such laws are derived for frame- and shell-based Gyroid, G-prime and Schwarz-D lattices using transversely isotropic elasticity for the bulk material. A nice feature of the approach is that the lower and upper additive manufacturing limits on the local density of the TMPS-based lattices are included properly. The performance of the approach is excellent, and this is demonstrated by solving several three-dimensional benchmark problems, e.g., the optimal macro-layout and local grading of Schwarz-D lattice for the established GE-bracket is identified using the presented approach.


2019 ◽  
Vol 822 ◽  
pp. 526-533
Author(s):  
Alexey Orlov ◽  
Dmitriy V. Masaylo ◽  
Igor A. Polozov ◽  
Pu Guang Ji

Due to the additive manufacturing process concept - layered synthesis of products, it becomes necessary to apply new approaches to the design of parts. One of the main tools that need to operate is numerical simulation, capable, with a skilful approach, to give an engineer an integrated procedure to the development of new products. Numerical modeling, in addition to carrying out strength calculations, includes topology optimization and the creation of lattice structures, through which it is possible to create lightweight products. New design meets requirements of strength characteristics. The use of this tool leads to a reduction in the amount of initial material and as a result - cost saving. In this paper, using the bracket as an example, was used the topology optimization method with subsequent redesign. The paper presents the results of calculations of the stress-strain state of the initial and final structures, allowing estimating the possible reduction in the mass of the product and the amount of consumable material in the manufacture of additive technologies.


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