Stress Field Guided Lattice Structure Design Based on Hexahedral Mesh

2019 ◽  
Author(s):  
Lingyun Liu ◽  
Yizhou Liao ◽  
Shuming Gao
Keyword(s):  
Stress Field ◽  
Lattice Structure ◽  
Design Method ◽  
Structure Design ◽  
Complex Structures ◽  
Hexahedral Mesh ◽  
Principal Stress Direction ◽  
Lattice Design ◽  
Solid Models ◽  
Wide Range

Abstract Lattice structures are promising for a wide range of applications. The development of additive manufacturing (AM) technology has made it possible to manufacture complex structures. However, designing the optimal lattices of complex solid models efficiently and automatically remains a challenge. Thus, we propose a novel stress-field-guided lattice design method to improve the mechanical properties of a lattice structure. Stress field is used to make the boundary struts of each cell of a lattice structure aligning to the principal stress direction while remaining conformal. Hierarchical cell templates are designed to reduce the computational burden of the cell optimization of a lattice structure. The proposed method is verified experimentally, and the experimental results prove the efficiency and validity of the proposed method.

Design of conformal lattice structures using the volumetric distance field based on parametric solid models

2020 ◽  
Vol 26 (6) ◽  
pp. 1005-1017
Author(s):  
Yan Liang ◽  
Feng Zhao ◽  
Dong-Jin Yoo ◽  
Bing Zheng
Keyword(s):  
Computational Models ◽  
Lattice Structure ◽  
Design Method ◽  
Design Framework ◽  
Content Type ◽  
Complex Lattice ◽  
Distance Field ◽  
Solid Models ◽  
Geometric Representations ◽  
Volumetric Distance Field

Purpose The purpose of this paper is to describe a novel design method to construct lattice structure computational models composed of a set of unit cells including simple cubic, body-centered cubic, face-centered cubic, diamond cubic and octet cubic unit cell. Design/methodology/approach In this paper, the authors introduce a new implicit design algorithm based on the computation of volumetric distance field (VDF). All the geometric components including lattice core structure and outer skin are represented with VDFs in a given design domain. This enables computationally efficient design of a computational model for an arbitrarily complex lattice structure. In addition, the authors propose a hybrid method based on the VDF and parametric solid models to construct a conformal lattice structure, which is oriented in accordance with the geometric form of the exterior surface. This method enables the authors to design highly complex lattice structure, computational models, in a consistent design framework irrespective of the complexity in geometric representations without sacrificing accuracy and efficiency. Findings Experimental results are shown for a variety of geometries to validate the proposed design method along with illustrative several lattice structure prototypes built by additive manufacturing techniques. Originality/value This method enables the authors to design highly complex lattice structure, computational models, in a consistent design framework irrespective of the complexity in geometric representations without sacrificing accuracy and efficiency.

scholarly journals Acoustic Structure Inverse Design and Optimization Using Deep Learning

2021 ◽  
Author(s):  
Xuecong Sun ◽  
Han Jia ◽  
Yuzhen Yang ◽  
Han Zhao ◽  
Yafeng Bi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Acoustic Waves ◽  
Design Method ◽  
Helmholtz Resonator ◽  
Structure Design ◽  
Acoustic Structure ◽  
Design And Optimization ◽  
Wide Range ◽  
Potential Applications ◽  
Coupling Parameters

Abstract From ancient to modern times, acoustic structures have been used to control the propagation of acoustic waves. However, the design of acoustic structures has remained a time-consuming and computational resource-consuming iterative process. In recent years, deep learning has attracted unprecedented attention for its ability to tackle hard problems with large datasets, achieving state-of-the-art results in various tasks. In this work, an acoustic structure design method is proposed based on deep learning. Taking the design of multiorder Helmholtz resonator as an example, we experimentally demonstrate the effectiveness of the proposed method. Our method is not only able to give a very accurate prediction of the geometry of acoustic structures with multiple strong-coupling parameters, but also capable of improving the performance of evolutionary approaches in optimization for a desired property. Compared with the conventional numerical methods, our method is more efficient, universal and automatic, and it has a wide range of potential applications, such as speech enhancement, sound absorption and insulation.

scholarly journals Leaf Vein-Inspired Bionic Design Method for Heat Exchanger Infilled with Graded Lattice Structure

Aerospace ◽  
2021 ◽  
Vol 8 (9) ◽  
pp. 237
Author(s):  
Haoyu Deng ◽  
Junpeng Zhao ◽  
Chunjie Wang
Keyword(s):  
Heat Exchanger ◽  
Heat Dissipation ◽  
Lattice Structure ◽  
Design Method ◽  
Mapping Method ◽  
Structure Design ◽  
Bionic Design ◽  
Leaf Vein ◽  
Transient Thermal ◽  
Graded Lattice

Due to its excellent performance and high design freedom, the lattice structure has shown excellent capabilities and considerable potential in aerospace and other fields. This paper proposes a method to map the biometric model to the lattice structure. Taking leaf veins as bionic objects, they are used to generate a bionic design with a gradient lattice structure to improve the performance of a heat exchanger. In order to achieve the above goals, this article also proposes a leaf vein model and a mapping method that combine the leaf vein model with the lattice structure. A series of transient thermal finite element simulations was conducted to evaluate and compare the heat dissipation performance of different designs. The analysis results show that the combination of the bionic design and the lattice structure effectively improves the heat dissipation performance of the lattice structure heat exchanger. The results indicate that the application of bionic design in lattice structure design has feasibility and predictable potential.

Lattice Structure Design Advisor for Additive Manufacturing Using Gaussian Process

2017 ◽  
Author(s):  
Tsz Ling Elaine Tang ◽  
Yan Liu ◽  
Da Lu ◽  
Erhan Batuhan Arisoy ◽  
Suraj Musuvathy
Keyword(s):  
Additive Manufacturing ◽  
Structural Properties ◽  
Structural Design ◽  
Lattice Structure ◽  
Structure Design ◽  
Structural Performance ◽  
Design Parameters ◽  
Use Case ◽  
Lattice Structures ◽  
Lattice Design

Additive manufacturing (AM) exemplifies the potential of lattice structures to revolutionize structural design. It enables light weight lattice structures to be produced while maintaining the desirable structural performance. Lattice design can vary in different shapes and dimensions. Obtaining the structural performance of a particular lattice structure design is not a straight-forward process. Significant effort is required to perform mechanical testing experiments or to perform finite element analysis (FEA) to characterize the lattice design. In view of that, a guidance system to determine lattice design parameters based on desired functional performance for a specific lattice type is developed, which can be used in interactive design processes and workflows. Homogenization using FEA experiments is applied to characterize the macroscopic lattice structural properties. Mechanical properties of orthotropic cubic lattice f2ccz are estimated. It follows with a design of experiment study to characterize the effective structural properties of 39 lattices with respect to lattice design parameters (unit cell length and strut diameter). A Gaussian process is applied to develop models relating the lattice design parameter to macroscopic structural properties (forward model), and vice versa (inverse model). Both the forward and inverse models are examined and shown to be capable of modeling the FEA experimental dataset of 39 lattices. To illustrate the potential application of the lattice design advisor framework, a structural design use case including lattice part is presented. In the use case, the lattice structure design advisor is proven to be able to estimate an accurate homogenized material property of arbitrary lattice design parameter. This lattice structure design advisor can simplify and streamline the design, modeling and simulation process of lattice-filled structural designs.

scholarly journals Nano-imprinted subwavelength gratings as polarizing beamsplitters

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Julian Wüster ◽  
Yannick Bourgin ◽  
Patrick Feßer ◽  
Arne Behrens ◽  
Stefan Sinzinger
Keyword(s):  
Nanoimprint Lithography ◽  
Optical Measurement ◽  
Design Method ◽  
Optical Systems ◽  
Surface Metrology ◽  
Measurement Systems ◽  
Common Path ◽  
Dielectric Coatings ◽  
Subwavelength Gratings ◽  
Wide Range

AbstractPolarizing beamsplitters have numerous applications in optical systems, such as systems for freeform surface metrology. They are classically manufactured from birefringent materials or with stacks of dielectric coatings. We present a binary subwavelength-structured form-birefringent diffraction grating, which acts as a polarizing beamsplitter for a wide range of incidence angles −30∘…+30∘. We refine the general design method for such hybrid gratings. We furthermore demonstrate the manufacturing steps with Soft-UV-Nanoimprint-Lithography, as well as the experimental verification, that the structure reliably acts as a polarizing beamsplitter. The experimental results show a contrast in efficiency for TE- and TM-polarization of up to 1:18 in the first order, and 34:1 in the zeroth order. The grating potentially enables us to realize integrated compact optical measurement systems, such as common-path interferometers.

scholarly journals Fabrication and Compressive Behavior of a Micro-Lattice Composite by High Resolution DLP Stereolithography

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 785
Author(s):  
Chow Shing Shin ◽  
Yu Chia Chang
Keyword(s):  
High Resolution ◽  
Lattice Structure ◽  
Low Cost ◽  
Hierarchical Structures ◽  
Dip Coating ◽  
Unit Cell ◽  
Digital Light Processing ◽  
Unit Cell Size ◽  
Wide Range ◽  
And Performance

Lattice structures are superior to stochastic foams in mechanical properties and are finding increasing applications. Their properties can be tailored in a wide range through adjusting the design and dimensions of the unit cell, changing the constituent materials as well as forming into hierarchical structures. In order to achieve more levels of hierarchy, the dimensions of the fundamental lattice have to be small enough. Although lattice size of several microns can be fabricated using the two-photon polymerization technique, sophisticated and costly equipment is required. To balance cost and performance, a low-cost high resolution micro-stereolithographic system has been developed in this work based on a commercial digital light processing (DLP) projector. Unit cell lengths as small as 100 μm have been successfully fabricated. Decreasing the unit cell size from 150 to 100 μm increased the compressive stiffness by 26%. Different pretreatments to facilitate the electroless plating of nickel on the lattice structure have been attempted. A pretreatment of dip coating in a graphene suspension is the most successful and increased the strength and stiffness by 5.3 and 3.6 times, respectively. Even a very light and incomplete nickel plating in the interior has increase the structural stiffness and strength by more than twofold.

scholarly journals Multi-Branch Cable Harness Layout Design Based on Genetic Algorithm with Probabilistic Roadmap Method

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Yingfeng Zhao ◽  
Jianhua Liu ◽  
Jiangtao Ma ◽  
Linlin Wu
Keyword(s):  
Genetic Algorithm ◽  
Topological Structure ◽  
Design Method ◽  
Route Planning ◽  
Layout Design ◽  
Structure Design ◽  
Prototype System ◽  
Cable Harness ◽  
Probabilistic Roadmap ◽  
Probabilistic Roadmap Method

AbstractCurrent studies on cable harness layouts have mainly focused on cable harness route planning. However, the topological structure of a cable harness is also extremely complex, and the branch structure of the cable harness can affect the route of the cable harness layout. The topological structure design of the cable harness is a key to such a layout. In this paper, a novel multi-branch cable harness layout design method is presented, which unites the probabilistic roadmap method (PRM) and the genetic algorithm. First, the engineering constraints of the cable harness layout are presented. An obstacle-based PRM used to construct non-interference and near to the surface roadmap is then described. In addition, a new genetic algorithm is proposed, and the algorithm structure of which is redesigned. In addition, the operation probability formula related to fitness is proposed to promote the efficiency of the branch structure design of the cable harness. A prototype system of a cable harness layout design was developed based on the method described in this study, and the method is applied to two scenarios to verify that a quality cable harness layout can be efficiently obtained using the proposed method. In summary, the cable harness layout design method described in this study can be used to quickly design a reasonable topological structure of a cable harness and to search for the corresponding routes of such a harness.

ECA Methodology for Fatigue Design of Risers and Flowlines

2007 ◽  
Author(s):  
C. H. Luk ◽  
T. J. Wang
Keyword(s):  
Fracture Mechanics ◽  
Design Method ◽  
Steel Catenary Riser ◽  
Fatigue Design ◽  
Wide Range ◽  
Fatigue And Fracture ◽  
Level 3 ◽  
Fatigue Loads ◽  
Vessel Motion ◽  
Level 2

Engineering Criticality Assessment (ECA) is a procedure based on fracture mechanics that may be used to supplement the traditional S-N approach and determine the flaw acceptance and inspection criteria in fatigue and fracture design of risers and flowlines. A number of design codes provide guidance for this procedure, e.g. BS-7910:2005 [1]. However, more investigations and example studies are still needed to address the design implications for riser and flowline applications. This paper provides a review of the existing ECA methodology, presents a fracture mechanics design method for a wide range of riser and flowline fatigue problems, and shows flaw size results from steel catenary riser (SCR) and flowline (FL) examples. The first example is a deepwater SCR subjected to fatigue loads due to vessel motion and riser VIV. The second example is a subsea flowline subjected to thermal fatigue loads. The effects of crack re-characterization and material plasticity on the Level-2 and Level-3 ECA results of the SCR and flowline examples are illustrated.

A Design Method for Thermosyphon Solar Domestic Hot Water Systems

1987 ◽  
Vol 109 (2) ◽  
pp. 150-155 ◽  
Author(s):  
M. P. Malkin ◽  
S. A. Klein ◽  
J. A. Duffie ◽  
A. B. Copsey
Keyword(s):  
Flow Rate ◽  
Design Method ◽  
Water Systems ◽  
Hot Water ◽  
Average Flow Rate ◽  
Domestic Hot Water ◽  
Average Flow ◽  
Solar Fraction ◽  
Wide Range ◽  
Flow Circuit

A modification to the f-Chart method has been developed to predict monthly and annual performance of thermosyphon solar domestic hot water systems. Stratification in the storage tank is accounted for through use of a modified collector loss coefficient. The varying flow rate throughout the day and year in a thermosyphon system is accounted for through use of a fixed monthly “equivalent average” flow rate. The “equivalent average” flow rate is that which balances the thermosyphon buoyancy driving force with the frictional losses in the flow circuit on a monthly average basis. Comparison between the annual solar fraction predited by the modified design method and TRNSYS simulations for a wide range of thermosyphon systems shows an RMS error of 2.6 percent.

Based on the Grey Relation Analysis of Ecological Composite Wall Seismic Performance Research

2013 ◽  
Vol 368-370 ◽  
pp. 1043-1047
Author(s):  
Yin Zhang ◽  
You Han ◽  
Shuai Liang
Keyword(s):  
Seismic Performance ◽  
Evaluation System ◽  
Design Method ◽  
Structure Design ◽  
Grey System Theory ◽  
Frame Structure ◽  
Wall Structure ◽  
Width Ratio ◽  
Grey System ◽  
Composite Wall

Ecological composite wall as ecological composite wall structure of the main stress components, the seismic performance is ecological composite wall structure seismic performance evaluation system of the main content. Based on the grey system theory, the grey correlation analysis to the key parameters (the mouth of the cave, frame structure, height to width ratio) change ecological composite wall test results are analyzed, the key parameters on the ecological composite wall the influence law of seismic performance, for choosing wall structure design method to provide basis.

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