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Symmetry
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Symmetry and Engineering Design
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Symmetry and Engineering Design

A special issue of Symmetry (ISSN 2073-8994). This special issue belongs to the section "Computer".

Deadline for manuscript submissions: closed (31 December 2018) | Viewed by 35301

Special Issue Editor

Prof. Dr. Fernando José Aguilar

E-Mail Website1 Website2
Guest Editor
Engineering Department, University of Almería, Carretera de Sacramento s/n. La Cañada de San Urbano, 04120 Almería, Spain
Interests: remote sensing; satellite imagery; OBIA; DEM quality; greenhouse mapping; greenhouse crop monitoring; forests
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Over the past few decades, fast-growing technologies based on computer graphics and computational geometry have introduced a number of engineering opportunities and challenges through already-matured disciplines, such as computer-aided design/engineering, computer vision and geomatics engineering. All these approaches are based on well-established theory and methods related to computer science applied to engineering design. Since engineering design addresses issues of creating and delivering innovative, useful, reliable and economical technical solutions to meet human wants or needs, computer-based methods add tremendous value to data capture and engineering simulations by enabling the creation of high-fidelity digital models that yield detailed insight into the performance of a proposed design or 3D environment modeling.

Bearing in mind the major role of symmetry in the efficiency of the digital processing and modeling of engineering problems (e.g., by reducing engineering simulation computational burden, improving human visual perception and aesthetics or helping fulfill functional, geometrical and manufacturing needs), the purpose of this Special Issue is to increase interdisciplinary interaction and collaboration in Engineering Design among several key related topics such as: Product design and development, computer-aided design (CAD), computer-aided engineering (CAE) and virtual simulation, computer-aided geometric design (CAGD), computer-aided manufacturing (CAM), geomatics engineering and computer graphics in bioengineering. Note that the list of suggested topics is not limited to the aforementioned ones, but it is open to related topics involving overview articles and progress reports on recent high-quality research and emerging applications concerning computational approaches focused on minimizing physical models and tests by using digital engineering simulation and 3D environment modeling in order to provide shorter product life cycles, reduced time to market, sharply targeted product performance and affordable costs in high quality engineering solutions.

Papers must be original contributions, not previously published or submitted to other journals. Submissions based on previous published or submitted conference papers may be considered provided they are considerably improved and extended.

Prof. Fernando J. Aguilar
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Symmetry is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (8 papers)

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Research

24 pages, 7071 KiB  
Article
Modeling and Control for a Multi-Rope Parallel Suspension Lifting System under Spatial Distributed Tensions and Multiple Constraints
by Naige Wang, Guohua Cao, Lu Yan and Lei Wang
Symmetry 2018, 10(9), 412; https://doi.org/10.3390/sym10090412 - 18 Sep 2018
Cited by 10 | Viewed by 3532
Abstract
The modeling and control of the multi-rope parallel suspension lifting system (MPSLS) are investigated in the presence of different and spatial distributed tensions; unknown boundary disturbances; and multiple constraints, including time varying geometric constraint, input saturation, and output constraint. To describe the system [...] Read more.
The modeling and control of the multi-rope parallel suspension lifting system (MPSLS) are investigated in the presence of different and spatial distributed tensions; unknown boundary disturbances; and multiple constraints, including time varying geometric constraint, input saturation, and output constraint. To describe the system dynamics more accurately, the MPSLS is modelled by a set of partial differential equations and ordinary differential equations (PDEs-ODEs) with multiple constraints, which is a nonhomogeneous and coupled PDEs-ODEs, and makes its control more difficult. Adaptive boundary control is a recommended method for position regulation and vibration degradation of the MPSLS, where adaptation laws and a boundary disturbance observer are formulated to handle system uncertainties. The system stability is rigorously proved by using Lyapunov’s direct method, and the position and vibration eventually diminish to a bounded neighborhood of origin. The original PDEs-ODEs are solved by finite difference method, and the multiple constraints problem is processed simultaneously. Finally, the performance of the proposed control is demonstrated by both the results of ADAMS simulation and numerical calculation. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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13 pages, 4536 KiB  
Article
Porous Scaffold Design Based on Minimal Surfaces: Development and Assessment of Variable Architectures
by Rita Ambu and Anna Eva Morabito
Symmetry 2018, 10(9), 361; https://doi.org/10.3390/sym10090361 - 25 Aug 2018
Cited by 30 | Viewed by 5214
Abstract
In tissue engineering, biocompatible porous scaffolds that try to mimic the features and function of the bone are of great relevance. In this paper, an effective method for the design of 3D porous scaffolds is applied to the modelling of structures with variable [...] Read more.
In tissue engineering, biocompatible porous scaffolds that try to mimic the features and function of the bone are of great relevance. In this paper, an effective method for the design of 3D porous scaffolds is applied to the modelling of structures with variable architectures. These structures are of interest since they are more similar to the stochastic configuration of real bone with respect to architectures made of a unit cell replicated in three orthogonal directions, which are usually considered for this kind of applications. This property configures them as, potentially, more suitable to satisfy simultaneously the biological requirements and those relative to the mechanical strength. The procedure implemented is based on the implicit surface modelling method and the use of a triply periodic minimal surface (TPMS), specifically, the Schwarz’s Primitive (P) minimal surface, whose geometry was considered for the development of scaffolds with different configurations. The representative structures modelled were numerically analysed by means of finite element analysis (FEA), considering them made of a biocompatible titanium alloy. The architectures considered were thus assessed in terms of the relationship between the geometrical configuration and the mechanical response to compression loading. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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10 pages, 3930 KiB  
Article
Symmetry in Regular Polyhedra Seen as 2D Möbius Transformations: Geodesic and Panel Domes Arising from 2D Diagrams
by Jose A. Diaz-Severiano, Valentin Gomez-Jauregui, Cristina Manchado and Cesar Otero
Symmetry 2018, 10(9), 356; https://doi.org/10.3390/sym10090356 - 21 Aug 2018
Cited by 2 | Viewed by 4247
Abstract
This paper shows a methodology for reducing the complex design process of space structures to an adequate selection of points lying on a plane. This procedure can be directly implemented in a bi-dimensional plane when we substitute (i) Euclidean geometry by bi-dimensional projection [...] Read more.
This paper shows a methodology for reducing the complex design process of space structures to an adequate selection of points lying on a plane. This procedure can be directly implemented in a bi-dimensional plane when we substitute (i) Euclidean geometry by bi-dimensional projection of the elliptic geometry and (ii) rotations/symmetries on the sphere by Möbius transformations on the plane. These graphs can be obtained by sites, specific points obtained by homological transformations in the inversive plane, following the analogous procedure defined previously in the three-dimensional space. From the sites, it is possible to obtain different partitions of the plane, namely, power diagrams, Voronoi diagrams, or Delaunay triangulations. The first would generate geo-tangent structures on the sphere; the second, panel structures; and the third, lattice structures. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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19 pages, 7069 KiB  
Article
Agustín de Betancourt’s Double-Acting Steam Engine: Geometric Modeling and Virtual Reconstruction
by José Ignacio Rojas-Sola, Belén Galán-Moral and Eduardo De la Morena-De la Fuente
Symmetry 2018, 10(8), 351; https://doi.org/10.3390/sym10080351 - 20 Aug 2018
Cited by 20 | Viewed by 4223
Abstract
In this paper, the geometric modeling and virtual reconstruction of the double-acting steam engine designed by Agustín de Betancourt in 1789 are shown. For this, the software Autodesk Inventor Professional is used, which has allowed us to obtain its geometric documentation. The material [...] Read more.
In this paper, the geometric modeling and virtual reconstruction of the double-acting steam engine designed by Agustín de Betancourt in 1789 are shown. For this, the software Autodesk Inventor Professional is used, which has allowed us to obtain its geometric documentation. The material for the research is available on the website of the Betancourt Project of the Canary Orotava Foundation for the History of Science. Almost all parts of the steam engine are drawn on the sheets, but due to the absence of scale and space, it is insufficient to obtain an accurate and reliable 3D CAD (Computer-Aided Design) model. For this reason a graphic scale has been adopted so that the dimensions of the elements are coherent. Also, it has been necessary to make some dimensional and geometric hypotheses, as well as restrictions of movement (degrees of freedom). Geometric modeling has made it possible to know that the system is balanced with the geometric center of the rocker arm shaft, and presents an energetic symmetry whose axis is the support of the parallelogram where the shaft rests: calorific energy to the left and mechanical energy to the right, with the rocker arm acting as a transforming element from one to the other. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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13 pages, 2954 KiB  
Article
Finite Element Study of a Threaded Fastening: The Case of Surgical Screws in Bone
by J. A. López-Campos, A. Segade, E. Casarejos, J. R. Fernández, J. A. Vilán and P. Izquierdo
Symmetry 2018, 10(8), 335; https://doi.org/10.3390/sym10080335 - 11 Aug 2018
Cited by 8 | Viewed by 5096
Abstract
This paper studies the stress state of a threaded fastening by using Finite Element (FE) models, applied to surgical screws in cortical bone. There is a general interest in studying the stress states induced in the different elements of a joint caused by [...] Read more.
This paper studies the stress state of a threaded fastening by using Finite Element (FE) models, applied to surgical screws in cortical bone. There is a general interest in studying the stress states induced in the different elements of a joint caused by the thread contact. Analytical models were an initial approach, and later FE models allowed detailed studies of the complex phenomena related to these joints. Different studies have evaluated standard threaded joints in machinery and structures, being the thread symmetric. However, surgical screws employ asymmetric thread geometry, selected to improve the stress level generated in the bone. Despite the interest and widespread use, there is scarce documentation on the actual effect of this thread type. In this work, we discuss the results provided by FE models with detailed descriptions of the contacts comparing differences caused by the materials of the joint, the thread geometry and the thread’s three-dimensional helical effects. The complex contacts at the threaded surfaces cause intense demand on computational resources that often limits the studies including these joints. We analyze the results provided by one commercial software package to simplify the threaded joints. The comparison with detailed FE models allows a definition of the level of uncertainty and possible limitations of this type of simplifications, and helps in making suitable choices for complex applications. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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12 pages, 3376 KiB  
Article
Novel Procedure for Designing and 3D Printing a Customized Surgical Template for Arthrodesis Surgery on the Sacrum
by Francesco Naddeo, Alessandro Naddeo, Nicola Cappetti, Emilio Cataldo and Riccardo Militio
Symmetry 2018, 10(8), 334; https://doi.org/10.3390/sym10080334 - 10 Aug 2018
Cited by 6 | Viewed by 3197
Abstract
In this article, the authors propose a novel procedure for designing a customized 3D-printed surgical template to guide surgeons in inserting screws into the sacral zone during arthrodesis surgeries. The template is characterized by two cylindrical guides defined by means of trajectories identified, [...] Read more.
In this article, the authors propose a novel procedure for designing a customized 3D-printed surgical template to guide surgeons in inserting screws into the sacral zone during arthrodesis surgeries. The template is characterized by two cylindrical guides defined by means of trajectories identified, based on standard procedure, via an appropriate Computer-Aided-Design (CAD)-based procedure. The procedure is based on the definition of the insertion direction by means of anatomical landmarks that enable the screws to take advantage of the maximum available bone path. After 3D printing, the template adheres perfectly to the bone surface, showing univocal positioning by exploiting the foramina of the sacrum, great maneuverability due to the presence of an ergonomic handle, as well as a break system for the two independent guides. These features make the product innovative. Thanks to its small size and the easy anchoring, the surgeon can simply position the template on the insertion area and directly insert the screws, without alterations to standard surgical procedures. This has the effect of reducing the overall duration of the surgery and the patient’s exposure to X-rays, and increasing both the safety of the intervention and the quality of the results. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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13 pages, 4506 KiB  
Article
Study of Morpho-Geometric Variables to Improve the Diagnosis in Keratoconus with Mild Visual Limitation
by Francisco Cavas-Martínez, Daniel G. Fernández-Pacheco, Francisco J. F. Cañavate, Jose S. Velázquez-Blázquez, Jose M. Bolarín and Jorge L. Alió
Symmetry 2018, 10(8), 306; https://doi.org/10.3390/sym10080306 - 01 Aug 2018
Cited by 17 | Viewed by 5053
Abstract
The validation of new methods for the diagnosis of incipient cases of Keratoconus (KC) with mild visual limitation is of great interest in the field of ophthalmology. During the asymmetric progression of the disease, the current diagnostic indexes do not record the geometric [...] Read more.
The validation of new methods for the diagnosis of incipient cases of Keratoconus (KC) with mild visual limitation is of great interest in the field of ophthalmology. During the asymmetric progression of the disease, the current diagnostic indexes do not record the geometric decompensation of the corneal curvature nor the variation of the spatial profile that occurs in singular points of the cornea. The purpose of this work is to determine the structural characterization of the asymmetry of the disease by using morpho-geometric parameters in KC eyes with mild visual limitation including using an analysis of a patient-specific virtual model with the aid of computer-aided design (CAD) tools. This comparative study included 80 eyes of patients classified as mild KC according to the degree of visual limitation and a control group of 122 eyes of normal patients. The metric with the highest area under the receiver operating characteristic (ROC) curve was the posterior apex deviation. The most prominent correlation was found between the anterior and posterior deviations of the thinnest point for the mild keratoconic cases. This new custom computational approach provides the clinician with a three-dimensional view of the corneal architecture when the visual loss starts to impair. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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17 pages, 856 KiB  
Article
A Bi-Level Programming Model for the Railway Express Cargo Service Network Design Problem
by Boliang Lin, Jianping Wu, Jiaxi Wang, Jingsong Duan and Yinan Zhao
Symmetry 2018, 10(6), 227; https://doi.org/10.3390/sym10060227 - 15 Jun 2018
Cited by 5 | Viewed by 3630
Abstract
Service network design is fundamentally crucial for railway express cargo transportation. The main challenge is to strike a balance between two conflicting objectives: low network setup costs and high expected operational incomes. Different configurations of these objectives will have different impacts on the [...] Read more.
Service network design is fundamentally crucial for railway express cargo transportation. The main challenge is to strike a balance between two conflicting objectives: low network setup costs and high expected operational incomes. Different configurations of these objectives will have different impacts on the quality of freight transportation services. In this paper, a bi-level programming model for the railway express cargo service network design problem is proposed. The upper-level model forms the optimal decisions in terms of the service characteristics, and the low-level model selects the service arcs for each commodity. The rail express cargo is strictly subject to the service commitment, the capacity restriction, flow balance constraints, and logical relationship constraints among the decisions variables. Moreover, linearization techniques are used to convert the lower-level model to a linear one so that it can be directly solved by a standard optimization solver. Finally, a real-world case study based on the Beijing–Guangzhou Railway Line is carried out to demonstrate the effectiveness and efficiency of the proposed solution approach. Full article
(This article belongs to the Special Issue Symmetry and Engineering Design)
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