Computer-aided Design System Research Articles

Study of the possibilities of additive technologies based on thermoplastic materials in a laboratory experiment and in studying the limitation of sand production in production wells

This paper presents the possibility of designing sand filters using the Compass-3D computer-aided design system of the Russian company ASCON, as well as creating an in-situ filter based on radiation cross-linked polyethylene. The filtration properties of filters and the possibility of sand retention by these models are experimentally studied.

Обоснование перспективной схемы кривошипного гидромотора для гидропривода опорно-поворотного устройства манипулятора лесовозного автопоезда

The task of increasing the efficiency of hydraulic manipulators with traditional column turning mechanisms installed on logging road trains can be solved by installing column turning mechanisms with crank hydraulic motors from hydraulic cylinders. Variants of the arrangement of hydraulic cylinders in a crank hydraulic motor were studied graph analytically by determining tangential and radial forces acting on the rotary column of the hydraulic manipulator. At first, calculations were performed based on static methods to evaluate the effect of forces on the rods of hydraulic cylinders in the working positions of the column rotation mechanism. After that, using the COMPASS computer-aided design system, circular diagrams of tangential and radial forces of the considered options for the arrangement of hydraulic cylinders in a crank hydraulic motor were constructed. Further, in the Microsoft Excel program, graphs of changes in tangential forces acting on the rotary column of the hydraulic manipulator were plotted. Schemes with five and six hydraulic cylinders have the best option of influencing the bearings in which the column is rotated. The ranges of radial forces for them ranged, respectively, from 3.32 to 22.07 kN and from 11.175 to 11.297 kN, and tangential forces – from 257.893 to 285.274 kN, and from 300.471 to 354.059 kN, which can be used in the design of new drive designs for turning columns of hydraulic manipulators. For the practical implementation of the proposed design of the crank hydraulic motor, it is planned to make a rational choice of the location of the hydraulic cylinders of the crank hydraulic motor on the frame of the logging road train on the basis of simulation modeling.

Geoinformation technologies of computer-aided design of public places in urban areas: problems and experience (on the example of Saransk)

The paper considers the possibilities of using modern software products to solve the problems of computer (including geoinformation) design of public places in urban areas, first of all, the AutoCAD computer-aided design system. The identified features of program use, its advantages and disadvantages, strong features and problems are presented, proven ways to overcome the latter are indicated. Based on the analysis of the experience of several projects of designing public places in Saransk (the capital of the Republic of Mordovia), carried out by the authors on the basis of topographic surveys of different years accompished by employees of LLC "Geostroiziskaniya", LLC "Cadastral Center", LLC "RNITS", materials are presented that give an idea of the options for incorrect and correct topography and illustrate the most common disadvantages of topographic bases, main steps of their processing and creation of a two-dimensional and three-dimensional topographic basis are shown on the example of the object "Novotroitsky shopping and office center". A number of indirect problems is also identified, generally related to computer-aided design of public places in urban areas, including problems with the use of licensed software, and really proven ways to overcome them are shown. This allowed to develop and practically implement geoinformation technology for computer-aided design of public places in urban areas.

Влияние формы тороидальной задней поверхности на углы режущего клина и механические напряжения вдоль режущей кромки сверла

Introduction. Drilling holes with standard tolerance varying from IT8 to IT12 is widely used in industrial production. However, at present time, there are neither comprehensive studies, nor scientifically justified recommendations for the rational choice of the geometry of the cutting part of drills with a toroidal flank surface. Therefore, the computer-aided design (CAD) of new drill designs with a toroidal flank surface and finite element modeling (FEM) of the stressed state of its cutting part are important tasks. The purpose of the work is reducing both the range of change in the rake angle and the wedge angle of the cutting wedge along the cutting edge from the periphery to the center and the equivalent stresses in the cutting wedge. In this paper we investigate changes in the rake and wedge angles of the cutting wedge depending on the radius of the generatrix line of the toroidal flank surface as well as changes in equivalent stresses in the cutting wedge, which depend on changes in the radius of the generatrix line of the toroidal flank surface. The research methods include the fundamentals of the theory of cutting, CAD methods, and the FEM, which was applied in this work to new drill designs. Results and discussion. It is found that the range of changes in the rake angle and the wedge angle of the cutting wedge of the drill decreases compared to the standard design with decreasing radius of the generatrix line of the flank surface. A CAD system for drills with a toroidal flank surface is developed. As a result, the range of changes in the rake angle along the cutting edge decreased by 86 % for a drill with a minimum radius of the generatrix line of the toroidal surface compared to that with the conical flank surface, the range of the wedge angle of the cutting wedge decreased by 56 %, and the maximum equivalent stresses decreased by 2.13 times. It is also important to note that in this case, the wedge angle is close to constant for half of the drill tooth. These indicators exceed those for existing designs of the twist drills that indicate the key achievement of this paper.

Optimization of Human-computer Interaction in Computer Aided Design System Based on User Behavior and Design Psychology

Optimization of Human-computer Interaction in Computer Aided Design System Based on User Behavior and Design Psychology

Адаптация библиотеки элементов ПО Revit для использования в отечественной САПР-системе Renga

The article touches upon the issue related to the transition of design and construction organizations to domestic software products within the framework of import substitution, related to the lack of libraries of elements used in digital information models. To solve this issue, it is proposed to use two approaches of different complexity to translate existing libraries of elements of digital information models in organizations that used the foreign AutoDesk Revit software package within the framework of information modeling technology into a data format supported by the domestic Renga computer-aided design system. Each of the described approaches has a number of its own advantages and disadvantages, which are defined in the context of the use of these software packages and are described in this article. Within the framework of the article, for each approach, detailed instructions are also provided with a description of each step that allows you to adapt the library of elements between the software complexes of the foreign developer AutoDesk, and the domestic - Renga Software. Thus, using the described approaches for the adaptation of the library of elements between foreign and domestic software complexes, it is possible to neutralize one of the issues related to the transition to the domestic complex of the Renga computer-aided design system.

Topology Guaranteed B-Spline Surface/Surface Intersection

The surface/surface intersection technique serves as one of the most fundamental functions in modern Computer Aided Design (CAD) systems. Despite the long research history and successful applications of surface intersection algorithms in various CAD industrial software, challenges still exist in balancing computational efficiency, accuracy, as well as topology correctness. Specifically, most practical intersection algorithms fail to guarantee the correct topology of the intersection curve(s) when two surfaces are in near-critical positions, which brings instability to CAD systems. Even in one of the most successfully used commercial geometry engines ACIS, such complicated intersection topology can still be a tough nut to crack. In this paper, we present a practical topology guaranteed algorithm for computing the intersection loci of two B-spline surfaces. Our algorithm well treats all types of common and complicated intersection topology with practical efficiency, including those intersections with multiple branches or cross singularities, contacts in several isolated singular points or highorder contacts along a curve, as well as intersections along boundary curves. We present representative examples of these hard topology situations that challenge not only the open-source geometry engine OCCT but also the commercial engine ACIS. We compare our algorithm in both efficiency and topology correctness on plenty of common and complicated models with the open-source intersection package in SISL, OCCT, and the commercial engine ACIS.

Mathematical Modelling in Light and Engineering Education

The development of computer technology and mathematical methods for solving the global illumination equation gave rise to computer-aided lighting design systems, which in turn led to a genuine revolution in the practice of lighting design. Deep use of information technologies is possible only with a developed mathematical description of the light field in a lighting installation. It is the theory of the light field, based on the theory of radiation transfer, that allows us to present all lighting technology from a single conceptual point of view. The mathematical apparatus of the theory of the light field is the basis of the algorithms of all modern programs for the calculation of lighting installations, lighting devices, radiation, reflection, and transmission of light by real objects. As a result, there was a need for a significant change in light and engineering education. At the subdepartment of Light and Engineering of the NRU “MEI”, following modern trends, new and new courses have appeared and are appearing, allowing students to obtain relevant knowledge. One of the new courses planned at the subdepartment is a course of mathematical modelling in light and engineering. It involves an in-depth study of the internal structure of computer-aided design systems, which will allow obtaining specialists capable of solving non-standard tasks, creating funds for solving these tasks and conducting research.

DEVELOPMENT OF A DATABASE FOR STORING AND EXCHANGING GEOMETRIC INFORMATION

As a part of the work on the research and development of information technology for converting archival drawing, design and technological documentation into an electronic model of a product, there is often a need to create a data storage and management system, that will allow storing and processing simultaneously all types of geometric and graphic data present on the various stages of the product life cycle. The capabilities of traditional GGI storage methods have limitations, which makes it difficult to work with large volumes of data and complicates the process of accessing the necessary elements. The goal of this article is to develop a database with high performance, reliability and flexibility to meet modern industry requirements. The current problem of developing a database for efficient storage and management of geological data, presented in the form of two-dimensional drawings and three-dimensional models is discussed. Proposed database architecture includes a central storage of graphical data and auxiliary modules for loading, processing, searching and visualizing information. Structures for efficiently storing information about drawing objects and components of 3D models, as well as various methods of indexing and searching for spatial data, such as quadtrees, spatial indexes and others, are considered. Proposed approaches are a promising direction for creating modern systems for storing and analyzing geometric data, which are in demand in many areas using modern computeraided design systems. The implementation of the described solutions will increase the speed of processing spatial information and improve the characteristics of systems for working with drawings and three-dimensional models.

Computer-Aided System for Layout of Fire Hydrants on Boards Designed Vessel Using the Particle Swarm Optimization Algorithm

Abstract The functional layout of fire safety equipment in technical spaces of ships is a time-consuming process. When designing a ship fire protection system, the designer must manually position each system component in such a way as to meet the requirements of regulations arising from the technical specification, various legal regulations of maritime conventions and classification societies of the vessel to be designed. Layout of fire hydrants assisted by a computer that is based on pre-defined criteria and various constraints could significantly support the designer in working easier and faster. This paper presents a prototype computer-aided design system that enables optimal placement of fire hydrants using the metaheuristic Particle Swarm Optimization (PSO) algorithm. This algorithm was used in Rhinoceros 3D software with its Grasshopper plugin for visualizing the arrangement of fire safety equipment. Various solution arrangements compared with the fire hydrant placement in real ships are illustrated by a case study. Demonstrating how design work can be facilitated and what potential benefits can be achieved are presented as well.

OPTIMIZATION OF TECHNOLOGICAL SCHEME OF WATER VAPOR PRODUCTION PROCESS

The development of modern technological processes for processing natural hydrocarbon raw materials and the optimal operation of existing production facilities is impossible without the use of modeling programs that have a high accuracy in describing the parameters of technological processes and allow studying these processes without significant material and time costs. Such model studies are of great importance not only for the design, but for the functioning of existing industries, as they allow us to take into account the influence of external factors on the performance of existing industries. Currently, a large number of software tools for modeling chemical technological processes are available to process engineers. When designing process flow diagrams for oil refineries and petrochemical plants, different departments of design institutes perform different types of work, using different software. The same applies to the so-called BIM - technologies implemented by installation and technological departments and the subsequent use of constructed installation diagrams in the existing production. Thus, this article discusses the problem of transferring data from the UniSim Design technological process modeling program to the AVEVA Everything3D computer-aided design systems for further use in the design process of the obtained design data of selected technological equipment. The technological process of steam generation was simulated in the UniSim Design program. An original module for transferring data to AVEVA Everything3D has been developed. The article presents the results of the module.

Comparing the Effect of Multi-Media-Based and Traditional Teaching Methods on Single Crown Preparation Factors Using CAD System

Background: This study aimed to determine the effect of multimedia-based and traditional teaching methods on the quality of dental student preparation by evaluating its smoothness, occlusal reduction, and the presence of undercut in the pre-clinic period. Methods: This study was conducted on 60 pre-clinical dental students, who were divided into two groups of A and B. Group A was trained through Multimedia-based teaching methods, including PowerPoint, instructor demonstration, and procedural videos, and group B was trained by traditional education methods, which only included instructor demonstration. The computer-aided design (CAD) system was used to evaluate the preparation factors of smoothness, presence of undercuts, and occlusal reduction on the second premolar and first molar teeth. Results: A significant difference was found between the frequency of smoothness in two education groups for teeth 5 and 6 (P = 0.026, P = 0.022). However, there was no significant difference between the frequency distribution of occlusal reduction in the two education groups (P = 0.383 and 0.168, for teeth 5 and 6, respectively) and was no significant difference between the undercut frequency in the two education groups (P = 0.365 and 0.078 for teeth 5 and 6, respectively). Conclusions: Based on the results, multimedia-based education can effectively promote two challenging preparation factors, including occlusal reduction and smoothness among pre-clinical students.

EXPERIENCE OF SYNTHESIS OF MULTITOOL SETTINGS IN APPLICATION TO MODERN CONDITIONS

The trends in the production of special equipment for mass production are analyzed and the prospects for the use of multi-tool blocks for such equipment are established. The questions of synthesis of variants of multi-tool machining for parts with a large number of machined sides and machining surfaces are considered. Three groups of factors of a technological, geometrical and technical nature are established, which have a dominant influence on the compatibility of machining with tools in one tool block. Their allowable values and the proposed matrix of compatibility of technological operations performed are established. Based on the research carried out, a refined method for the synthesis of multi-tool blocks of special machine tools is proposed, the layout of which is based on the maximum use of unified modules and assemblies. This approach does not depend on the technological operations performed and on which modules can be used for the design implementation of the proposed tool block layout. The proposed method is focused on the use of computer-aided design systems in the process of creating machine tools with an aggregate-modular layout for mass production. It is based on the wide use of the knowledge base of the technical characteristics and technological capabilities of the modules used and makes it possible to initially configure the synthesis system for specific tasks solved at the enterprise by establishing admissible boundary parameters.

Повышение производительности и отказоустойчивости схемотехнических САПР на основе методов диакоптики и автоматизации управления мультитенатными компонентами

An approach to building automated control of multi-tenant components of information systems is described. The main advantages of using discretizing multi-tenant shells for building distributed information systems are reflected and justified. Methods for managing the infrastructure of a distributed system as a code are given. Technologies and their settings for automating management at different stages of the life cycle of a software system built on the basis of discretizing multi-tenant shells are presented. The solution to the problem of dual use of the process manager in a container based on the Linux operating system in a manual and automated version in the context of managing life cycle stages using the CI / CD approach is described. A technique for modeling weakly coupled electronic circuits based on the technology of calculating large electronic circuits in parts is proposed, by selecting weakly coupled subcircuits between which there are no inductive connections and the condition for the concentration of control and controlled variable dependent sources within a separate subcircuit is met. It is shown that the implementation of the diacoptic approach to modeling large loosely coupled circuits significantly increases the productivity of the computational process, which is especially important in the development of distributed computer-aided design systems. It is proposed to build and transform the description of the simulated circuit to use generalized signal graphs that display the equations of the circuit in a generalized cause-and-effect form.

BASIC DUTIES OF DIGITAL PRODUCTION

The term “digital manufacturing” can be interpreted quite broadly. Initially, computer-aided design systems fell under this definition. Then they began to include product life cycle management systems. It is clear that cloud technologies, additive manufacturing and augmented reality will also influence the development of digital manufacturing.

Optimal settings for different tooth types in the virtual bracket removal technique.

To determine the optimal settings for reconstructing the buccal surfaces of different tooth types using the virtual bracket removal (VBR) technique. Ten postbonded digital dentitions (with their original prebonded dentitions) were enrolled. The VBR protocol was carried out under five settings from three commonly used computer-aided design (CAD) systems: OrthoAnalyzer (O); Meshmixer (M); and curvature (G2), tangent (G1), and flat (G0) from Geomagic Studio. The root mean squares (RMSs) between the reconstructed and prebonded dentitions were calculated for each tooth and compared with the clinically acceptable limit (CAL) of 0.10 mm. The overall prevalences of RMSs below the CAL were 66.80%, 70.08%, 62.30%, 94.83%, and 56.15% under O, M, G2, G1, and G0, respectively. For the upper dentition, the mean RMSs were significantly lower than the CAL for all tooth types under G1 and upper incisors and canines under M and G2. For the lower dentition, the mean RMSs were significantly lower than the CAL for all tooth types under G1 and lower incisors and canines under M, G2, and G0 (all P < .05). Additionally, the mean RMSs of all teeth under G1 were significantly lower than those under the other settings (all P < .001). The optimal settings varied among different tooth types. G1 performed best for most tooth types compared to the other four settings.

Компьютерное моделирование при проектировании комбинированного инструмента для формообразования фасонных поверхностей

The article discusses issues related to the design of tools for shaping surfaces of complex shapes, characteristic of modern engineering production. Often, designers take the path of increasing the degree of curvature of the surfaces of parts in order to improve their strength, ergonomic and aesthetic properties. The analysis carried out by the authors shows the presence of significant problems when processing such surfaces using traditional shaping methods. The authors state that in some cases it is advisable to use electrical non-contact methods for processing such surfaces. In this regard, the article provides an analysis of the features of digital design of technological equipment using modern computer-aided design systems. The author's approach to the design and manufacture of an electrode-tool is proposed, taking into account its wear during operation for the formation of curved surfaces using electrical processing methods. The authors have disclosed a technique for digital modeling and setting tool parameters based on programmable dependencies associated both with the nature of the removal of a layer of material due to the influence of an electric field in the processing zone, and with the features of manufacturing the tool using additive technologies with subsequent metallization of the working surfaces of the tool.

Comparative Analysis of the Fracture Resistance of a Polymeric Material for 3D Printing and a Milled Polymethylmethacrylate Material as Interim Material for Fixed Partial Dentures: New Material Updated

The aim of this study was to evaluate and compare the fracture resistance of a temporary three-unit fixed dental prosthesis (FDP) made of a new polymeric material obtained by an additive technique (3DPP) using a computer-aided design and manufacturing (CAD/CAM) system, comparing the prosthesis to the respective outcomes of temporary polymethylmethacrylate (PMMA) FDPs obtained by a subtractive technique (milling). Methods: Three-unit FDPs were 3D printed using a polymeric material (n = 20) or milled using polymethylmethacrylate (n = 20). After thermocycling at 5000 cycles at extreme temperatures of 5 °C and 55 °C in distilled water, each specimen was subjected to a compression test on a universal testing machine at a rate of 0.5 mm/min until failure occurred, recording the value in newtons (N). Results: There were statistically significant differences (p-value &lt; 0.005) between the PMMA material (2104.7 N; SD = 178.97 N) and 3DPP (1000.8 N; SD = 196.4 N). Conclusions: The fracture resistance of the PDFs manufactured from milled PMMA showed higher values for fracture resistance. However, the resistance of the 3DPP showed acceptable values under mechanical load; this notable advance in the resistance of printed materials consolidates them as an important alternative to use in interim indirect restorations.

FGR-Net: Interpretable fundus image gradeability classification based on deep reconstruction learning

The performance of diagnostic Computer-Aided Design (CAD) systems for retinal diseases depends on the quality of the retinal images being screened. Thus, many studies have been developed to evaluate and assess the quality of such retinal images. However, most of them did not investigate the relationship between the accuracy of the developed models and the quality of the visualization of interpretability methods for distinguishing between gradable and non-gradable retinal images. Consequently, this paper presents a novel framework called “FGR-Net” to automatically assess and interpret underlying fundus image quality by merging an autoencoder network with a classifier network. The FGR-Net model also provides an interpretable quality assessment through visualizations. In particular, FGR-Net uses a deep autoencoder to reconstruct the input image in order to extract the visual characteristics of the input fundus images based on self-supervised learning. The extracted features by the autoencoder are then fed into a deep classifier network to distinguish between gradable and ungradable fundus images. FGR-Net is evaluated with different interpretability methods, which indicates that the autoencoder is a key factor in forcing the classifier to focus on the relevant structures of the fundus images, such as the fovea, optic disk, and prominent blood vessels. Additionally, the interpretability methods can provide visual feedback for ophthalmologists to understand how our model evaluates the quality of fundus images. The experimental results showed the superiority of FGR-Net over the state-of-the-art quality assessment methods, with an accuracy of >89% and an F1-score of >87%. The code is publicly available at https://github.com/saifalkh/FGR-Net.

Multi-scale SE-residual network with transformer encoder for myocardial infarction classification

In recent years, there has been an increase in the number of deaths caused by heart disease. The design of computer-aided systems for the diagnosis of heart diseases, especially myocardial infarction (MI), has become a hot topic. The diagnosis of MI is a classification task. Electrocardiogram (ECG) is one of the most important tools for diagnosing heart disease. ECG signals are classified into corresponding MI categories based on their extracted features. Thus, the diagnosis of MI depends on the feature extraction of the ECG signal. Because signal processing methods, such as wavelet transform, may not effectively extract hidden features, researchers nowadays turn to using convolutional neural networks to solve the problem of hidden feature extraction. However, this approach ignores the role of temporal information. we proposed a new network called Multi-scale SE-Residual Network with Transformer encoder (MRTNet) to extract hidden features and temporal information features better. The data processed are localized to heartbeat units based on the way cardiologists diagnose myocardial infarction. Inspired by multi-scale learning, the sampling module was designed to acquire heartbeat units at different scales. We provided a processing model for multi-scale data, called the feature extraction module. The residual network with SE block and Customized Pooling Component (CPC) was used to extract global and local features of the heartbeat units. A Transformer encoder was used to extract the common features of the previous module’s output. The common features at different scales were fused to provide the basis for the classification task. The experiment was conducted on the public PTB-XL dataset. MRTNet achieved a higher accuracy and F1 score than other models by approximately 2%. Furthermore, MRTNet demonstrated a superior AUC of approximately 0.77. It is a superior classifier when compared to other models. The results demonstrate the effectiveness of the designed multi-scale architecture. And it provides a way into exploring further potential information from ECG signals.