Lattice Structure Design for Additive Manufacturing: Unit Cell Topology Optimization

2019 ◽  
Author(s):  
Bradley Hanks ◽  
Mary Frecker
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Lattice Structure ◽  
Optimization Method ◽  
Structure Design ◽  
Unit Cell ◽  
Lattice Structures ◽  
Design For Additive Manufacturing ◽  
Structure Topology

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.

3D Additive Lattice Topology Optimization: A Unit Cell Design Approach

2020 ◽  
Author(s):  
Bradley Hanks ◽  
Mary Frecker
Keyword(s):  
Topology Optimization ◽  
Lattice Structure ◽  
Unit Cell ◽  
Optimization Approach ◽  
Lattice Structures ◽  
Cell Design ◽  
Ground Structure ◽  
Structure Topology ◽  
Cell Topology

Abstract Non-stochastic lattice structures are patterned after the unit cell topology and are of interest to the research and design communities for improving stiffness to weight ratios and/or metamaterial design. While additive manufacturing (AM) increases design freedom, it remains difficult to design or select an appropriate unit cell topology. In this work, a ground structure topology optimization approach is developed for unit cell design. Using a multi-objective evolutionary algorithm, this framework incorporates a library of different objectives, constraints, and penalties. The Additive Lattice Topology Optimization (ALTO) approach generates novel lattice structures for AM from the selected design objectives. A key purpose of this framework is incorporating AM process considerations into the optimization through objectives, constraints, and penalty functions for improved manufacturability. Two case studies presented in this work demonstrate ALTO’s ability to generate novel lattice structures with specific functionality while accounting for AM process constraints for laser powder bed fusion. Case Study 1 is an example of generating a lattice structure for heat sink applications. Case Study 2 demonstrates creation of three novel lattices with different stiffness properties, each with the same volume fraction. Using ground structure topology optimization and incorporating AM process considerations, ALTO is a unique approach for improved lattice structure design.

scholarly journals Toward the integration of lattice structure-based topology optimization and additive manufacturing for the design of turbomachinery components

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401985978
Author(s):  
Enrico Boccini ◽  
Rocco Furferi ◽  
Lapo Governi ◽  
Enrico Meli ◽  
Alessandro Ridolfi ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Lattice Structure ◽  
Three Dimensional ◽  
Optimization Method ◽  
Lattice Structures ◽  
Stiffness Properties ◽  
Maximum Stiffness ◽  
Layer Manufacturing ◽  
Innovative Materials

Used in several industrial fields to create innovative designs, topology optimization is a method to design a structure characterized by maximum stiffness properties and reduced weights. By integrating topology optimization with additive layer manufacturing and, at the same time, by using innovative materials such as lattice structures, it is possible to realize complex three-dimensional geometries unthinkable using traditional subtractive techniques. Surprisingly, the extraordinary potential of topology optimization method (especially when coupled with additive manufacturing and lattice structures) has not yet been extensively developed to study rotating machines. Based on the above considerations, the applicability of topology optimization, additive manufacturing, and lattice structures to the fields of turbomachinery and rotordynamics is here explored. Such techniques are applied to a turbine disk to optimize its performance in terms of resonance and mass reduction. The obtained results are quite encouraging since this approach allows improving existing turbomachinery components’ performance when compared with traditional one.

Rapid Modeling and Design Optimization of Multi-Topology Lattice Structure Based on Unit-Cell Library

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Yuan Liu ◽  
Shurong Zhuo ◽  
Yining Xiao ◽  
Guolei Zheng ◽  
Guoying Dong ◽  
...  
Keyword(s):  
Topology Optimization ◽  
Lattice Structure ◽  
Structure Design ◽  
Parametric Modeling ◽  
Unit Cell ◽  
Element Analysis ◽  
Structure Generation ◽  
Cell Library ◽  
Unit Cells ◽  
Property Space

Abstract Lightweight lattice structure generation and topology optimization (TO) are common design methodologies. In order to further improve potential structural stiffness of lattice structures, a method combining the multi-topology lattice structure design based on unit-cell library with topology optimization is proposed to optimize the parts. First, a parametric modeling method to rapidly generate a large number of different types of lattice cells is presented. Then, the unit-cell library and its property space are constructed by calculating the effective mechanical properties via a computational homogenization methodology. Third, the template of compromise Decision Support Problem (cDSP) is applied to generate the optimization formulation. The selective filling function of unit cells and geometric parameter computation algorithm are subsequently given to obtain the optimum lightweight lattice structure with uniformly varying densities across the design space. Lastly, for validation purposes, the effectiveness and robustness of the optimized results are analyzed through finite element analysis (FEA) simulation.

Design and Analysis of Lattice Structures for Additive Manufacturing

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Christiane Beyer ◽  
Dustin Figueroa
Keyword(s):  
Additive Manufacturing ◽  
Lattice Structure ◽  
Cost Savings ◽  
Unit Cell ◽  
Cnc Machining ◽  
Numerical Control ◽  
Full Potential ◽  
Lattice Structures ◽  
Cell Structures ◽  
Bending Load

Additive manufacturing (AM) enables time and cost savings in the product development process. It has great potential in the manufacturing of lighter parts or tools by the embedding of cellular/lattice structures that consume less material while still distributing the necessary strength. Less weight and less material consumption can lead to enormous energy and cost savings. Although AM has come a long way over the past 25–30 years since the first technology was invented, the design of parts and tools that capitalize on the technology do not yet encompass its full potential. Designing for AM requires departing from traditional design guidelines and adopting new design considerations and thought structures. Where previous manufacturing techniques (computer numerical control (CNC) machining, casting, etc.) often necessitated solid parts, AM allows for complex parts with cellular and lattice structure implementation. The lattice structure geometry can be manipulated to deliver the level of performance required of the part. The development and research of different cell and lattice structures for lightweight design is of significant interest for realizing the full potential of AM technologies. The research not only includes analysis of existing software tools to design and optimize cell structures, but it also involves design consideration of different unit cell structures. This paper gives a solid foundation of an experimental analysis of additive manufactured parts with diverse unit cell structures in compression and flexural tests. Although the research also includes theoretical finite element analysis (FEA) of the models, the results are not considered here. As an introduction, the paper briefly explains the basics of stress and strain relationship and summarizes the test procedure and methods. The tests concentrate primarily on the analysis of 3D printed polymer parts manufactured using PolyJet technology. The results show the behavior of test specimens with different cell structures under compression and bending load. However, the research has been extended and is still ongoing with an analysis of selective laser melted test specimens in aluminum alloy AlSi10Mg.

Designing of Topology Optimized Parts for Additive Manufacturing

2019 ◽  
Vol 822 ◽  
pp. 526-533
Author(s):  
Alexey Orlov ◽  
Dmitriy V. Masaylo ◽  
Igor A. Polozov ◽  
Pu Guang Ji
Keyword(s):  
Numerical Simulation ◽  
Topology Optimization ◽  
Additive Manufacturing ◽  
Strain State ◽  
New Products ◽  
Optimization Method ◽  
Additive Technologies ◽  
Lattice Structures ◽  
Initial Material ◽  
Topology Optimization Method

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.

scholarly journals A Topology Optimization Method for Stochastic Lattice Structures

2021 ◽  
pp. 235-240
Author(s):  
Filippo Cucinotta ◽  
Marcello Raffaele ◽  
Fabio Salmeri
Keyword(s):  
Topology Optimization ◽  
3D Printing ◽  
Structural Optimization ◽  
High Performance ◽  
Three Dimensional ◽  
Optimization Method ◽  
Lattice Structures ◽  
Low Weight ◽  
Topology Optimization Method

AbstractStochastic lattice structures are very powerful solutions for filling three-dimensional spaces using a generative algorithm. They are suitable for 3D printing and are well appropriate to structural optimization and mass distribution, allowing for high-performance and low-weight structures. The paper shows a method, developed in the Rhino-Grasshopper environment, to distribute lattice structures until a goal is achieved, e.g. the reduction of the weight, the harmonization of the stresses or the limitation of the strain. As case study, a cantilever beam made of Titan alloy, by means of SLS technology has been optimized. The results of the work show the potentiality of the methodology, with a very performing structure and low computational efforts.

scholarly journals Design of Variable-Density Structures for Additive Manufacturing Using Gyroid Lattices

2017 ◽  
Author(s):  
Botao Zhang ◽  
Kunal Mhapsekar ◽  
Sam Anand
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Volume Fraction ◽  
Complex Geometry ◽  
Lattice Structure ◽  
Variable Density ◽  
Light Weight ◽  
Lattice Structures ◽  
Density Mapping ◽  
Usage Cost

Additive manufacturing (AM) processes enable the creation of lattice structures having complex geometry which offer great potential for designing light weight parts. The combination of AM and cellular lattice structures provide promising design solutions in terms of material usage, cost and part weight. However, the geometric complexity of the structures calls for a robust methodology to incorporate the lattices in parts designs and create optimum light weight designs. This paper proposes a novel method for designing light weight variable-density lattice structures using gyroids. The parametric 3D implicit function of gyroids has been used to control the shape and volume fraction of the lattice. The proposed method is then combined with the density distribution information from topology optimization algorithm. A density mapping and interpolation approach is proposed to map the output of topology optimization into the parametric gyroids structures which results in an optimum lightweight lattice structure with uniformly varying densities across the design space. The proposed methodology has been validated with two test cases.

scholarly journals Optimization Approaches in Design for Additive Manufacturing

2019 ◽  
Vol 1 (1) ◽  
pp. 809-818
Author(s):  
Stefano Rosso ◽  
Gianpaolo Savio ◽  
Federico Uriati ◽  
Roberto Meneghello ◽  
Gianmaria Concheri
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Geometric Modeling ◽  
Lattice Structure ◽  
Software Tool ◽  
Lattice Structures ◽  
Commercial Software ◽  
Lightweight Structure ◽  
Sharp Edges ◽  
Manufacturing Technologies

AbstractNowadays, topology optimization and lattice structures are being re-discovered thanks to Additive Manufacturing technologies, that allow to easily produce parts with complex geometries.The primary aim of this work is to provide an original contribution for geometric modeling of conformal lattice structures for both wireframe and mesh models, improving previously presented methods. The secondary aim is to compare the proposed approaches with commercial software solutions on a piston rod as a case study.The central part of the rod undergoes size optimization of conformal lattice structure beams diameters using the proposed methods, and topology optimization using commercial software tool. The optimized lattice is modeled with a NURBS approach and with the novel mesh approach, while the topologically optimized part is manually remodeled to obtain a proper geometry. Results show that the lattice mesh modelling approach has the best performance, resulting in a lightweight structure with smooth surfaces and without sharp edges at nodes, enhancing mechanical properties and fatigue life.

scholarly journals A Comparison of Miniature Lattice Structures Produced by Material Extrusion and Vat Photopolymerization Additive Manufacturing

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2163
Author(s):  
Rafael Guerra Silva ◽  
María Josefina Torres ◽  
Jorge Zahr Viñuela
Keyword(s):  
Additive Manufacturing ◽  
Energy Absorption ◽  
Lattice Structure ◽  
Solid Material ◽  
Unit Cell ◽  
Lattice Structures ◽  
Compression Tests ◽  
Material Extrusion ◽  
Lower Accuracy ◽  
Manufacturing Methods

In this paper, we study the capabilities of two additive manufacturing technologies for the production of lattice structures, namely material extrusion and vat photopolymerization additive manufacturing. A set of polymer lattice structures with diverse unit cell types were built using these additive manufacturing methods and tested under compression. Lattice structures built using material extrusion had lower accuracy and a lower relative density caused by the air gaps between layers, but had higher elastic moduli and larger energy absorption capacities, as a consequence of both the thicker struts and the relatively larger strength of the feedstock material. Additionally, the deformation process in lattices was analyzed using sequential photographs taken during the compression tests, evidencing larger differences according to the manufacturing process and unit-cell type. Both additive manufacturing methods produced miniature lattice structures with similar mechanical properties, but vat polymerization should be the preferred option when high geometrical accuracy is required. Nevertheless, as the solid material determines the compressive response of the lattice structure, the broader availability of feedstock materials gives an advantage to material extrusion in applications requiring stiffer structures or with higher energy absorption capabilities.

Topology Optimization for Multi-Material Lattice Structures With Tailorable Material Properties for Additive Manufacturing

2019 ◽  
Author(s):  
Vysakh Venugopal ◽  
Matthew McConaha ◽  
Sam Anand
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
Material Properties ◽  
Coefficient Of Thermal Expansion ◽  
Lattice Structure ◽  
Manufacturing Processes ◽  
Lattice Structures ◽  
High Mechanical Strength ◽  
Unit Cells ◽  
Significant Attention

Abstract Structurally optimized lattices have gained significant attention since the commercialization of additive manufacturing (AM). These lattices, which can be categorized as metamaterials, are used in aviation and aerospace industries due to their capacity to perform well under extreme structural, thermal, or acoustic loading conditions. This research focuses on the design of a unit cell of a multi-material lattice structure using topology optimization to be manufactured using multi-material additive manufacturing processes. The algorithm combined with octant symmetry and support elimination filters yields optimized unit cells with overall reduction in effective coefficient of thermal expansion and thermal conductivity with high mechanical strength. Such unit cells can be used in multi-material additive manufacturing to generate lattice structures with optimized structural and thermal properties.

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