The Design Process of Additively Manufactured Mesoscale Lattice Structures: A Review

2018 ◽  
Vol 18 (4) ◽  
Author(s):  
Francesco Tamburrino ◽  
Serena Graziosi ◽  
Monica Bordegoni
Keyword(s):  
Design Process ◽  
Three Dimensional ◽  
Lattice Structures ◽  
Functional Requirements ◽  
Software Developers ◽  
Holistic View ◽  
Whole Process ◽  
Unit Cells ◽  
3D Printed ◽  
The Impact

This review focuses on the design process of additively manufactured mesoscale lattice structures (MSLSs). They are arrays of three-dimensional (3D) printed trussed unit cells, whose dimensions span from 0.1 to 10.0 mm. This study intends to detail the phases of the MSLSs design process (with a particular focus on MSLSs whose unit cells are made up of a network of struts and nodes), proposing an integrated and holistic view of it, which is currently lacking in the literature. It aims at guiding designers' decisions with respect to the settled functional requirements and the manufacturing constraints. It also aims to provide an overview for software developers and researchers concerning the design approaches and strategies currently available. A further objective of this review is to stimulate researchers in exploring new MSLSs functionalities, consciously considering the impact of each design phase on the whole process, and on the manufactured product.

Managing Design Process Complexity: A Value-of-Information Based Approach for Scale and Decision Decoupling

2007 ◽  
Author(s):  
Jitesh H. Panchal ◽  
Christiaan J. J. Paredis ◽  
Janet K. Allen ◽  
Farrokh Mistree
Keyword(s):  
Design Process ◽  
Value Of Information ◽  
Cooling System ◽  
Design Decision ◽  
Interaction Patterns ◽  
Functional Requirements ◽  
Design Processes ◽  
A Value ◽  
Complex Design ◽  
The Impact

Design processes for multiscale, multifunctional systems are inherently complex due to the interactions between scales, functional requirements, and the resulting design decisions. While complex design processes that consider all interactions lead to better designs; simpler design processes where some interactions are ignored are faster and resource efficient. In order to determine the right level of simplification of design processes, designers are faced with the following questions: a) how should complex design-processes be simplified without affecting the resulting product performance? and b) how can designers quantify and evaluate the appropriateness of different design process alternatives? In this paper, the first question is addressed by introducing a method for determining the appropriate level of simplification of design processes — specifically through decoupling of scales and decisions in a multiscale problem. The method is based on three constructs: interaction patterns to model design processes, intervals to model uncertainty resulting from decoupling of scales and decisions, and value of information based metrics to measure the impact of simplification on the final design outcome. The second question is addressed by introducing a value-of-information based metric called improvement potential for quantifying the appropriateness of design process alternatives from the standpoint of product design requirements. The metric embodies quantitatively the potential for improvement in the achievement of product requirements by adding more information for design decision making. The method is illustrated via a datacenter cooling system design example.

DESIGN STRATEGY OF THREE-DIMENSIONAL PRINTED CAGES TO REDUCE IMPACT-INDUCED DEBRIS ALONG THE LOAD-TRANSFERRING PATH

2021 ◽  
pp. 2050021
Author(s):  
Shang-Chih Lin ◽  
Yu-Pao Hsu ◽  
Ching-Hsiao Yu ◽  
Chun-Ming Chen ◽  
Po-Quang Chen
Keyword(s):  
Finite Element ◽  
Cellular Structure ◽  
Three Dimensional ◽  
Peak Stress ◽  
Transforaminal Lumbar Interbody Fusion ◽  
Design Strategy ◽  
Cellular Structures ◽  
The Finite Element Method ◽  
3D Printed ◽  
The Impact

Peri-implant debris certainly lead to osteolysis, necrosis, pseudotumor formation, tissue granulation, fibrous capsule contractions, and even implant failure. For the three-dimensional (3D) printed cage, impaction during cage insertion is one of the most potential sources of fracture debris. A finite-element study was carried out to reduce the impact-induced debris of the 3D-printed cage. This study focused on the design strategy of solid and cellular structures along the load-transferring path. Using the finite-element method, the cellular structure of the transforaminal lumbar interbody fusion (TLIF) cage was systematically modified in the following four variations: a noncellular cage (NC), a fully cellular (FC) cage, a solid cage with a cellular structure in the middle concave (MC) zone, and a strengthened cage (SC) in the MC zone. Three comparison indices were considered: the stresses at the cage-instrument interfaces, in the MC zone, and along the specific load-transferring path. The NC and FC were the least and most highly stressed variations at the cage-instrument interfaces and in the MC zone, respectively. Along the entirely load-transferring path, the FC was still the most highly stressed variation. It showed a higher risk of stress fracture for the FC cage. For the MC and SC, the MC zone was consistently more stressed than the directly impacted zone. The further strengthened design of the SC had a lower peak stress (approximately 29.2%) in the MC zone compared with the MC. Prior to 3D printing, the load-transferring path from the cage-instrument interfaces to the cage-tissue interfaces should be determined. The cage-instrument interfaces should be printed as a solid structure to avoid impact-induced fracture. The other stress-concentrated zones should be cautiously designed to optimize the coexistence strategy of the solid and cellular structures.

scholarly journals Parameters Affecting the Mechanical Properties of Three-Dimensional (3D) Printed Carbon Fiber-Reinforced Polylactide Composites

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2456
Author(s):  
Demei Lee ◽  
Guan-Yu Wu
Keyword(s):  
Mechanical Properties ◽  
Carbon Fiber ◽  
3D Printing ◽  
Three Dimensional ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Bed Temperature ◽  
3D Printed ◽  
The Impact

Three-dimensional (3D) printing is a manufacturing technology which creates three-dimensional objects layer-by-layer or drop-by-drop with minimal material waste. Despite the fact that 3D printing is a versatile and adaptable process and has advantages in establishing complex and net-shaped structures over conventional manufacturing methods, the challenge remains in identifying the optimal parameters for the 3D printing process. This study investigated the influence of processing parameters on the mechanical properties of Fused Deposition Modelling (FDM)-printed carbon fiber-filled polylactide (CFR-PLA) composites by employing an orthogonal array model. After printing, the tensile and impact strengths of the printed composites were measured, and the effects of different parameters on these strengths were examined. The experimental results indicate that 3D-printed CFR-PLA showed a rougher surface morphology than virgin PLA. For the variables selected in this analysis, bed temperature was identified as the most influential parameter on the tensile strength of CFR-PLA-printed parts, while bed temperature and print orientation were the key parameters affecting the impact strengths of printed composites. The 45° orientation printed parts also showed superior mechanical strengths than the 90° printed parts.

How Software Refactoring Impacts Execution Time

2022 ◽  
Vol 31 (2) ◽  
pp. 1-23
Author(s):  
Luca Traini ◽  
Daniele Di Pompeo ◽  
Michele Tucci ◽  
Bin Lin ◽  
Simone Scalabrino ◽  
...  
Keyword(s):  
Execution Time ◽  
Careful Consideration ◽  
Software Performance ◽  
Functional Requirements ◽  
Software Developers ◽  
Software Refactoring ◽  
Performance Benchmarks ◽  
History Of ◽  
External Behavior ◽  
The Impact

Refactoring aims at improving the maintainability of source code without modifying its external behavior. Previous works proposed approaches to recommend refactoring solutions to software developers. The generation of the recommended solutions is guided by metrics acting as proxy for maintainability (e.g., number of code smells removed by the recommended solution). These approaches ignore the impact of the recommended refactorings on other non-functional requirements, such as performance, energy consumption, and so forth. Little is known about the impact of refactoring operations on non-functional requirements other than maintainability. We aim to fill this gap by presenting the largest study to date to investigate the impact of refactoring on software performance, in terms of execution time. We mined the change history of 20 systems that defined performance benchmarks in their repositories, with the goal of identifying commits in which developers implemented refactoring operations impacting code components that are exercised by the performance benchmarks. Through a quantitative and qualitative analysis, we show that refactoring operations can significantly impact the execution time. Indeed, none of the investigated refactoring types can be considered “safe” in ensuring no performance regression. Refactoring types aimed at decomposing complex code entities (e.g., Extract Class/Interface, Extract Method) have higher chances of triggering performance degradation, suggesting their careful consideration when refactoring performance-critical code.

scholarly journals Finite Element Modeling in the Design Process of 3D Printed Pneumatic Soft Actuators and Sensors

Robotics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 52 ◽  
Author(s):  
Charbel Tawk ◽  
Gursel Alici
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Design Process ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Robotic Systems ◽  
Element Modeling ◽  
And Topology ◽  
3D Printed ◽  
Soft Actuators

The modeling of soft structures, actuators, and sensors is challenging, primarily due to the high nonlinearities involved in such soft robotic systems. Finite element modeling (FEM) is an effective technique to represent soft and deformable robotic systems containing geometric nonlinearities due to large mechanical deformations, material nonlinearities due to the inherent nonlinear behavior of the materials (i.e., stress-strain behavior) involved in such systems, and contact nonlinearities due to the surfaces that come into contact upon deformation. Prior to the fabrication of such soft robotic systems, FEM can be used to predict their behavior efficiently and accurately under various inputs and optimize their performance and topology to meet certain design and performance requirements. In this article, we present the implementation of FEM in the design process of directly three-dimensional (3D) printed pneumatic soft actuators and sensors to accurately predict their behavior and optimize their performance and topology. We present numerical and experimental results to show that this approach is very effective to rapidly and efficiently design the soft actuators and sensors to meet certain design requirements and to save time, modeling, design, and fabrication resources.

Homogenization of Vibrating Periodic Lattice Structures

2005 ◽  
Author(s):  
Stefano Gonella ◽  
Massimo Ruzzene
Keyword(s):  
Smart Materials ◽  
Periodic Structures ◽  
Three Dimensional ◽  
Periodic Pattern ◽  
Periodic Lattice ◽  
Lattice Structures ◽  
Equivalent Representation ◽  
Detailed Model ◽  
Wide Range ◽  
Unit Cells

The paper describes a homogenization technique for periodic lattice structures. The analysis is performed by considering the irreducible unit cell as a building block that defines the periodic pattern. In particular, the continuum equivalent representation for the discrete structure is sought with the objective of retaining information regarding the local properties of the lattice, while condensing its global behavior into a set of differential equations. These equations can then be solved either analytically or numerically, thus providing a model which involves a significantly lower number of variables than those required for the detailed model of the assembly. The methodology is first tested by comparing the dispersion relations obtained through homogenization with those corresponding to the detailed model of the unit cells and then extended to the comparison of exact and approximate harmonic responses. This comparison is carried out for both one-dimensional and two-dimensional assemblies. The application to three-dimensional structures is not attempted in this work and will be approached in the future without the need for substantial conceptual changes in the theoretical procedure. Hence the presented technique is expected to be applicable to a wide range of periodic structures, with applications ranging from the design of structural elements of mechanical and aerospace interest to the optimization of smart materials with attractive mechanical, thermal or electrical properties.

Numerical Simulation and Study on Three-Dimensional Flow Field of Wind Turbine Impeller

2012 ◽  
Vol 236-237 ◽  
pp. 1286-1291
Author(s):  
Feng Wang ◽  
De You Liu ◽  
Ling Zhou ◽  
Xiang Dong Qian
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Design Process ◽  
Wind Farm ◽  
Dynamic Performance ◽  
Three Dimensional ◽  
Aerodynamic Performance ◽  
Calculation Error ◽  
The Impact ◽  
Turbine Impeller

hree-dimensional aerodynamic performance of wind turbine impeller is one of the most important elements in the wind turbine design process; its accuracy directly impacts the efficiency and stability of wind turbine operation. As the current numerical simulation for three-dimensional aerodynamic performance of wind turbine impeller does not fully consider the impact of the rotation effect of the wind turbine and other factors, a relatively large calculation error can be resulted. In this paper, a 1.65MW Vestas wind turbine was taken as an model, and design process of wind turbine blade was made. Also, three-dimensional numerical simulation was made to get a comprehensive dynamic performance of the wind turbine, and the influence of wind turbine power and wind farm efficiency by the pitch angle and wind speed were made.

scholarly journals A Proposed In Vitro Methodology for Assessing the Accuracy of Three-Dimensionally Printed Dental Models and the Impact of Storage on Dimensional Stability

2021 ◽  
Vol 11 (13) ◽  
pp. 5994
Author(s):  
Li Hsin Lin ◽  
Joshua Granatelli ◽  
Frank Alifui-Segbaya ◽  
Laura Drake ◽  
Derek Smith ◽  
...  
Keyword(s):  
Dimensional Stability ◽  
Reference Model ◽  
Three Dimensional ◽  
Posterior Region ◽  
Digital Light Processing ◽  
Dental Models ◽  
3D Printed ◽  
T1 And T2 ◽  
The Impact

The objective of this study was to propose a standardised methodology for assessing the accuracy of three-dimensional printed (3DP) full-arch dental models and the impact of storage using two printing technologies. A reference model (RM) comprising seven spheres was 3D-printed using digital light processing (MAX UV, MAX) and stereolithography (Form 2, F2) five times per printer. The diameter of the spheres (n = 35) represented the dimensional trueness (DT), while twenty-one vectors (n = 105) extending between the sphere centres represented the full-arch trueness (FT). Samples were measured at two (T1) and six (T2) weeks using a commercial profilometer to assess their dimensional stability. Significant (p < 0.05) contraction in DT occurred at T1 and T2 with a medium deviation of 108 µm and 99 µm for MAX, and 117 µm and 118 µm for F2, respectively. No significant (p > 0.05) deviations were detected for FT. The detected median deviations were evenly distributed across the arch for MAX at <50 µm versus F2, where the greatest error of 278 µm was in the posterior region. Storage did not significantly impact the model’s DT in contrast to FT (p < 0.05). The proposed methodology was able to assess the accuracy of 3DP. Storage significantly impacted the full-arch accuracy of the models up to 6 weeks post-printing.

Fabrication, Mechanics, and Reliability Analysis for 3D Printed Lattice Designs

2021 ◽  
Author(s):  
Nitin Nagesh Kulkarni ◽  
Stephen Ekwaro-Osire ◽  
Paul Egan
Keyword(s):  
Sensitivity Analysis ◽  
3D Printing ◽  
Reliability Analysis ◽  
Yield Stress ◽  
Beam Diameter ◽  
Lattice Structures ◽  
Exponential Increase ◽  
Unit Cells ◽  
3D Printed ◽  
Probabilistic Failure Analysis

Abstract The use of 3D printing for lattice structures has led to advances in diverse applications benefitting from mechanically efficient designs. 3D printed lattices are often used to carry loads, however, printing defects and inconsistencies potentially hinder performance. Here, we investigate the design, fabrication, mechanics, and reliability of lattices with repeating cubic unit cells using probabilistic analysis. Lattices were designed with 500µm diameter beams and unit cell lengths from 0.8mm to 1.6mm. Lattices were printed with stereolithography and had average beam diameters from 509µm to 622µm, thereby demonstrating a deviation from design intentions. Mechanical experiments were conducted to quantify the exponential increase in yield stress for the relative density of lattices that facilitated probabilistic failure analysis. Sensitivity analysis demonstrated performance was most sensitive to fluctuations in beam diameter (74%) and less to lattice yield stress (8%) for lattices with 1.6mm unit cells while lattices with smaller 1.0mm unit cells were most sensitive to yield stress (48%) and to beam diameter (43%) fluctuations. These findings provide new insights linking design, fabrication, mechanics, and reliability analysis for improved system design that is crucial for engineers to consider as 3D printing becomes more widely adopted.

scholarly journals Comparative analysis of current 3D printed acetabular titanium implants

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Lorenzo Dall’Ava ◽  
Harry Hothi ◽  
Johann Henckel ◽  
Anna Di Laura ◽  
Paul Shearing ◽  
...  
Keyword(s):  
Outer Surface ◽  
Three Dimensional ◽  
Coordinate Measuring Machine ◽  
Titanium Implants ◽  
The Body ◽  
Lattice Structures ◽  
Micro Computed Tomography ◽  
Solid Region ◽  
3D Printed ◽  
Measuring Machine

Abstract Background The design freedom allowed by three-dimensional (3D) printing enables the production of acetabular off-the-shelf cups with complex porous structures. The only studies on these designs are limited to clinical outcomes. Our aim was to analyse and compare the designs of different 3D printed cups from multiple manufacturers (Delta TT, Trident II Tritanium and Mpact 3D Metal). Methods We analysed the outer surface of the cups using scanning electron microscopy (SEM) and assessed clinically relevant morphometric features of the lattice structures using micro-computed tomography (micro-CT). Dimensions related to the cup wall (solid, lattice and overall thickness) were also measured. Roundness and roughness of the internal cup surface were analysed with coordinate measuring machine (CMM) and optical profilometry. Results SEM showed partially molten titanium beads on all cups, significantly smaller on Trident II (27 μm vs ~ 70 μm, p < 0.0001). We found a spread of pore sizes, with median values of 0.521, 0.841 and 1.004 mm for Trident II, Delta TT and Mpact, respectively. Trident II was also significantly less porous (63%, p < 0.0001) than the others (Delta TT 72.3%, Mpact 76.4%), and showed the thinnest lattice region of the cup wall (1.038 mm, p < 0.0001), while Mpact exhibited the thicker solid region (4.880 mm, p < 0.0044). Similar roundness and roughness of the internal cup surfaces were found. Conclusion This was the first study to compare the designs of different 3D printed cups. A variability in the morphology of the outer surface of the cups and lattice structures was found. The existence of titanium beads on 3D printed parts is a known by-product of the manufacturing process; however, their prevalence on acetabular cups used in patients is an interesting finding, since these beads may potentially be released in the body.

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