Computer-aided Design Environment Research Articles

Development of a device for assessment of aortic root parameters and positioning of aortic valve cusps during aortic valve-sparing root replacement

Background. A promising method of surgical treatment of aneurysms of the root and ascending aorta (AA) with unchanged aortic valve (AV) cusps is aortic valve-sparing root replacement (VSRR) with AV reimplantation (David procedure). To date, there are no clear indications to make a choice in favor of valve-replacing or valve-sparing intervention. The result of visual evaluation and the choice of treatment method based on the surgeon’s experience remains the main criteria. Objective. In the experiment to develop a prototype and method of application of the device for positioning of AV cusps, which will simplify and standardize aortic valve-sparing root replacement, improve the results and increase the reproducibility of these operations. Design and methods. Three-dimensional (3D) modeling of the device components was performed in the parametric open-source computer-aided design environment FreeCAD 0.20.1. Two-dimensional sketches were converted into three-dimensional models and exported as stl files for 3D printing. Solid components of the model were made of polylactic acid (PLA-plastic), elastic components were made of rubber-like photopolymer (Dropstil F556 10 shore A) also by 3D printing using SLA technology. Results. The device consists of 2 similar ring-sizers of variable diameter connected by three struts of variable length. In the upper part of each of the struts fastenings to the distal ring represents T-shaped cutouts for temporary locking of the suture-holders passed through the commissures of the AV cusps. For proximal locking of the aortic graft and the proximal ring-sizer, 3 U-shaped sutures are used, passed from inside to outside through the AV ring, the proximal part of the graft and taken in the tourniquets. The diameters of the ring-sizers can be varied between 25–40 mm by rotating a worm drive. A graft is placed on the inner side of the device, the suture-holders attached to the tops of the commissures are locked in the T-shaped notches in the upper parts of the struts. The device will allow changing the position of the coaptation point, coaptation square and performing hydraulic tests in different positions of the cusps, as well as variable diameters at the level of the AV ring and sinotubular junction (25–40 mm). When the target position of the coaptation point, coaptation area and satisfactory hydraulic test result are achieved, the cusps with commissures are locked inside the graft and the device is removed. Conclusion. A new device has been developed to facilitate, reproduce, and standardize VSRR. The results obtained will facilitate and accelerate the performance of VSRR, increase the reproducibility of the technique, and reduce the risks of complications.

Large-Scale Solar Potential Analysis in a 3D CAD Framework as a Use Case of Urban Digital Twins

Solar radiation impacts diverse aspects of city life, such as harvesting energy with PV panels, passive heating of buildings in winter, cooling the loads of air-conditioning systems in summer, and the urban microclimate. Urban digital twins and 3D city models can support solar studies in the process of urban planning and provide valuable insights for data-driven decision support. This study examines the calculation of solar incident radiation at the city scale in Sofia using remote sensing data for the large shading context in a mountainous region and 3D building data. It aims to explore the methods of geometry optimisation, limitations, and performance issues of a 3D computer-aided design (CAD) tool dedicated to small-scale solar analysis and employed at the city scale. Two cases were considered at the city and district scales, respectively. The total face count of meshes for the simulations constituted approximately 2,000,000 faces. A total of 64,379 roofs for the whole city and 4796 buildings for one district were selected. All calculations were performed in one batch and visualised in a 3D web platform. The use of a 3D CAD environment establishes a seamless process of updating 3D models and simulations, while preprocessing in Geographic Information System (GIS) ensures working with large-scale datasets. The proposed method showed a moderate computation time for both cases and could be extended to include reflected radiation and dense photogrammetric meshes in the future.

A local–global optimization approach for maximizing the multiphysics frequency response of laminated functionally graded CNTs reinforced magneto-electro-elastic plates

Smart materials have garnered significant attention due to their distinct properties and potential applications in various engineering fields. In line with this, this study presents a local–global optimization approach aimed at maximizing the multiphysics frequency of laminated functionally graded carbon nanotube reinforced magneto-electro-elastic (FG-CNTMEE) plates. The laminated FG-CNTMEE plate is composed of layers of functionally graded carbon nanotubes embedded in an electro-elastic matrix, rendering it capable of exhibiting exceptional properties in response to magnetic and electric fields. To optimize its performance, a Balance Enhanced Symbiotic Organisms Search (BESOS) algorithm with new modifications of phases is proposed for global optimization, and integrated with a multiphysical isogeometric analysis using refined zigzag theory (MIARZ) for precise local–global analysis of laminated FG-CNTMEE plates within a Computer-Aided Design (CAD) environment. The effectiveness, robustness, and reliability of the proposed approach are demonstrated through numerical examples that highlight its applicability in achieving optimal designs for smart laminated FG-CNTMEE plates.

Dual-Level Framework for OpenBIM-Enabled Design Collaboration

Design coordination and collaboration are crucial in the architecture, engineering, and construction (AEC) industries, necessitating the integration of diverse disciplines and expertise to achieve unified and functional designs. Traditionally, these disciplines operate in isolation, leading to a fragmented design process. Building Information Modeling (BIM), recognized for its collaborative capabilities, presents an opportunity to revolutionize traditional design practices. However, existing research on BIM primarily assumes an ideal environment where all major participants use BIM models, overlooking the dynamics of mixed 2D Computer-aided Design (CAD) and 3D BIM environments. Addressing this research gap, this study aims to establish a dual-level OpenBIM-enabled collaborative design framework, enhancing the design process across various disciplines. The study employs a case study approach, applying this framework to an airport project in Chengdu, China. The airport includes different corridors that are similar in scope and scale but distinct enough to allow for a comparative study. The results demonstrate a 27% faster completion rate, a 98% reduction in design errors, and improved user satisfaction with the proposed method. The paper concludes by discussing the limitations of the study and suggesting avenues for future research.

G-code converter using interface system for a STEP file (ISO 10303)

The STEP file is the “standard for the exchange of product model data,” which is usually used to exchange geometric data in boundary representation (B-rep) between different computer-aided design (CAD) platforms. These data can be fully utilized and integrated into a larger manufacturing organization, such as a computer-aided manufacturing (CAM) environment for computer numerical control (CNC) machining applications based on ISO 6983. The 3D models of 2D machining profiles were created in CAD software and saved as STEP files. The data structure was analyzed by comparing the geometric entities of the CAD model and the STEP file. The algorithm was created using the hypertext preprocessor (PHP) programming language and produced a computer interface system to convert STEP files into G-code format. The machining blocks with profile machining features were simulated using a CNC simulator and PC-based open architecture control (OAC) software. The G-code was validated on a three-axis CNC milling machine, and the result was compared to the CAD model to confirm the machining profile. The integrated interface system I2S demonstrates its ability to interpret all 2D profiles and generate machining tool paths and G-code, allowing data flow between CAD and CAM environments and shortening product development cycles.

An Intelligent Method for Fault Location Estimation in HVDC Cable Systems Connected to Offshore Wind Farms

Large and remote offshore wind farms (OWFs) usually use voltage source converter (VSC) systems to transmit electrical power to the main network. Submarine high-voltage direct current (HVDC) cables are commonly used as transmission links. As they are liable to insulation breakdown, fault location in the HVDC cables is a major issue in these systems. Exact fault location can significantly reduce the high cost of submarine HVDC cable repair in multi-terminal networks. In this paper, a novel method is presented to find the exact location of the DC faults. The fault location is calculated using extraction of new features from voltage signals of cables’ sheaths and a trained artificial neural network (ANN). The results obtained from a simulation of a three-terminal HVDC system in power systems computer-aided design (PSCAD) environment show that the maximum percentage error of the proposed method is less than 1%.

STRENGTHENING APPLIED ORIENTATION OF SCHOOL NATURAL EDUCATION BY MEANS OF INFORMATION AND COMMUNICATION TECHNOLOGIES

The article reveals essence of the applied orientation of school education. Organizational and pedagogical conditions for the introduction of information and communication technologies in the practice of school work is determined. The application of such technologies in the educational process of the new Ukrainian school attaches special importance to the problem of strengthening the applied orientation of school natural education, development of computer-based ways of solving applied problems of industrial nature, filling the content of educational material with mathematical methods of displaying and processing information and reference support, etc. In order to visualize and define the system-creative relations of the concept of “applied orientation”, its structural and functional model which contains the main pedagogical objectives of school science education and possible ways to implement them is constructed. The pedagogical tasks reflect the goals of basic secondary education, as they present the main functions of the studied concept, determine its purpose and meaning of existence. Ways to implement the applied orientation are structural elements of the concept and reflect the actions and relationships in it.
 The main types of computer modeling used in IR support systems for teaching natural subjects, didactic possibilities of their use in teaching students of general secondary education are characterized. The analysis of interactive environments for solving applied problems using appropriate models is carried out. An algorithm for their design in various computer-aided design environments has been developed. Features of the formation of basic knowledge, practical skills in the use of measuring instruments, key competencies, cross-cutting skills and attitudes in computer-oriented environments are highlighted. In order to solve the tasks, the following methods and types of activities were used: the study of philosophical, psychological and pedagogical, scientific and methodological literature, advanced pedagogical experience, the content of curricula, programs, textbooks, didactic manuals for school science subjects and computer science, modeling of educational activities with the use of information and communication technologies, conversations, questionnaires, interviews and expert evaluation; experimental teaching using the developed system of tasks and diagnostics of student achievements; analysis of the results of educational activities using ICT; pedagogical experiment and statistical data processing.

Identification of Traction Electric Rolling Stock that Exceeds the Level of Interference in the Train Radio Communication Channel

The main methods for searching and determination of the level of signals are considered in the article. Their advantages and disadvantages are revealed. An algorithm for automatic search and determination of the level of interference in train radio communication channels has been developed. It makes it possible to identify traction electric rolling stock with an exceeding level of interference and carry out further transfer of information to the operator. Based on the algorithm a signal conversion device has been developed. The simulation of work of this device has been carried out in the computer-aided design and simulation environment "EasyEDA".

FEM Simulation as a Tool for Planning and Optimizing the Rubber Pad Forming Process

Manufacturing press-formed metallic components by conventional methods needs a burdensome trial-and-error process to set up the technology, which success depends, largely, upon the operator’s skill and experience. The finite element (FE) simulations of sheet-metal-forming processes assist the manufacturing engineer to design a forming process by shifting the costly press-shop try-outs to the computer-aided design environment. The purpose of applying numerical simulations of a manufacturing process such as rubber-pad forming is to avoid the trial-and-error procedure and shorten the development phases when tight times-to-market are demanded. The main aim of the investigation presented in this paper was to develop a numerical model that would be able to, successfully, simulate a rubber-pad forming process. The finite-element method was used for blank- and rubber-behavior predictions during the process. The study focused on simulating and investigating significant parameters (such as forming force and stress and strain distribution in a blank) which are associated with the rubber-pad forming process, also the capabilities of this process regarding the manufacturing of aircraft wing ribs and ships. As a result, the stress and strain distribution in a blank as well as the forming force were identified. The experimental analysis of a rib with a lightning hole showed a close correlation between the FE simulations and the experimental results.

Development of recommendations for optimizing the geometry of tower cranes

Problem. Special attention is paid to maintaining tower cranes in good working order and serviceable condition through their proper operation. Unfortunately, violation of the operating rules can lead to an emergency situation. In this case, both the crane operator and other workers on the construction site may be injured. And in some cases even to death. Therefore, the development of measures for safe operation is very important. It is also important to ensure sufficient strength of the load-bearing steel structures, which make up the bulk of the tower cranes, the breakdown of which leads to significant costs to restore the working condition of the tower. Goal. The goal of the work is to develop a method of interactive graphical modeling of three-dimensional models of metal structures with the use of a forced variation of their dimensions in the environment of computer-aided design – Autodesk Inventor package. Methodology. The solution of the set tasks implied the use of computer modeling methods with the use of modern 3-D modeling programs. Experimental studies were also carried out to determine loading modes. Results. A comprehensive methodology has been developed that uses the method of interactive graphical modeling of three-dimensional models of metal structures with a forced variation of their dimensions in the computer-aided design environment - Autodesk Inventor. It allows you to obtain rational parameters of the main elements of the tower crane – tower, boom, and others. This technique significantly increases the productivity and quality of the designer's work and reduces the time for research (tower cranes) and design documentation. Originality. The method of interactive graphic modeling of three-dimensional models of metal structures on the example of the tower crane with the use of a forced variation of their dimensions in the computer-aided design environment – Autodesk Inventor package is offered. Practical value. The use of the proposed methodology will significantly improve the efficiency of the design and operation of tower cranes.

CUSTOMISED INFILL PATERNS FOR STREGHTENED 3D PARTS

The development of rapid prototyping technologies generates a strong concern for saving all types of materials while maintaining, or even increasing, the strength of 3d printed parts. One way to partially meet this requirement is to make models with a low degree of filling. However, the types of predefined filling structures, defined in the slicing programs, are relatively small in number, being based on repetitive patterns. In this paper it is proposed to make a specimen with a filling structure adapted to the expected stress that appear during operation. Model design can be done in any computer-aided design environment. The deformations of the modified specimen were compared with the deformations of some models with predefined filling structures, under the conditions of maintaining the same loads. This comparison allows to verify the strength of the specimen, under the conditions of using the same volume of material, compared to the models with predefined structure. In addition, conclusions can be drawn regarding the strength of various filling patterns and the time required to print the specimen. The favorable results create the premises of developing an algorithm that can allow the generation of some filling models optimized for different types of loads and eventually the possibility of applying the same concept of custom filling structure for other rapid prototyping technologies.

Полосно-пропускающий фильтр на метаволноводе

This article proposes an alternative method for designing miniature waveguide filters based on locally resonant metamaterials. Implementation of ultra-small metamaterial filters (metafilters) using the subwavelength direction mechanism in hollow waveguides loaded with small resonators. In particular, composite pin waveguides are used, constructed from a hollow metal tube loaded with a set of resonant pins that are spaced over deep subwavelength distances. In such structures, multiple resonance scattering leads to the emergence of a sub-λ mode with a tunable bandwidth below the induced hybridization gap. In order to guarantee compatibility with existing technologies, a subwavelength method of matching small filters with standard waveguide interfaces, which can be called a metaport, is proposed. Calculations were performed using the CST Studio computeraided design environment.

Полосно-пропускающий фильтр на прямоугольном волноводе с плоскопродольными тонкими диафрагмами

In modern microwave systems, a wide variety of frequency-selective devices are used, which are performed according to certain technologies. Waveguide microwave filters are currently a rapidly developing class of functional devices. The variety of manufacturing technologies, calculation methods and designs of such filters is great. In this paper, we consider a band-pass filter on a rectangular waveguide with a cross section of 35×15 mm, in which, instead of the classic thin plane-transverse diaphragms, plane-longitudinal diaphragms are used. Four classical rectangular windows are used as a resonant window, which makes it possible to conduct electrodynamic analysis and show good convergence of the calculation and simulation results. Calculations were performed using the computer-aided design environment CST Studio.

A computational design approach for multi-material 4D printing based on interlocking blocks assembly

4D printing is considered as a disruptive manufacturing technology for creating innovative devices able to evolve in their usage environment. By coupling additive manufacturing (AM) processes and active/passive materials under the effect of an energy stimulation, objects can change properties, shapes, or even functionalities. To achieve a desired shape-change, recent advances in computational design around digital materials require tackling multi-material 4D printing. However, the deposition of active and passive materials in a single run remains difficult due to the different AM techniques required. To overcome this limitation in the context of complex materials distributions, an original approach is to address multi-material 4D printing from the perspective of interlocking blocks assembly. Therefore, the objective of the paper is to propose a computational design approach that converts a multi-material 4D object with a computed digital materials distribution into suitable interlocking blocks. The latter can be printed separately using single material AM and then assembled to achieve the targeted shape change. An implementation of the approach via a dedicated plugin within a computer-aided design environment is presented. A case study is introduced to illustrate the relevance and the applicability of the proposed approach.

Topometry Optimization of Energy Absorbing Structure through Targeting Force-Displacement Method considering Tailor Rolled Blank Process

Inspired by topometry optimization, this work proposed a new design approach that mixed of targeting force-displacement (TFD) method and tailor rolled blank (TRB) process for thin-walled energy absorption structures, which has vast applied prospects in the aerospace and automotive industries. This method not only overcomes manufacturing difficulty caused by the TFD method based on topometry optimization but also provides a new idea for TRB energy absorption structure. The optimized results can be transferred to the computer aided design environment without additional postprocessing. Firstly, a uniform thickness constraint is introduced to make the designed structure have constant thickness distribution along desired direction; topometry optimization is carried out to use TFD method. Secondly, a method that can automatically divide the design domain is developed. The adjacent elements with smaller thickness differences are merged to form TRB subdomains based on the optimization results of forestep, and the TFD method is used again. Finally, TRB finite element modeling codes is developed. According to the second step, modeling of the transition zone is added to finally form the TRB structure that meets the requirements of manufacturing. This method is used to optimize the crashworthiness of the thin-walled tube under axial and oblique loading. Numerical results demonstrate the effectiveness of this method. Therefore, this method can be used to design high-efficiency energy absorber on aircraft or automobile, such as the strut of aircraft and energy absorption box of automobile.

EVALUATION OF STRUCTURAL FND FUNCTIONAL FEATURES OF REIMPLANTED AORTIC VALVE AFTER DAVID I PROCEDURE WITH THE USE OF HIGH-PRECISSION 3-DIMENSIONAL SEGMENTATION OF THE AORTIC ROOT

Aneurysm of the aortic root accompanied by aortic insufficiency is a common cardiovascular pathology. The optimal method of surgical treatment of this pathology is the reimplantation of the aortic valve into the aortic root synthetic prosthesis (David procedure). Currently, there is no comprehensive data on the influence of initial geometric parameters of the aortic root structures on the functioning of the reimplanted aortic valve after valve-preserving aortic root replacement. We have introduced a novel technique for creation and segmentation of a three-dimensional reconstruction of the aortic valve and root, which involves the sequential application of two computer-aided design environments: In Vesalius v 3.1.1 (Centro de Tecnologia da Informação Renato Archer (CTI)) and 3- Matic v. 13.0 (Materialise, Leuven, Belgium). The proposed method allows accurate measurement and evaluation of spatial parameters of the AV leaflets, fibrous ring, sinuses of Valsalva and sinotubular junction. The developed technique was used to evaluate the anatomical and functional features of the aortic valve in a 68-year-old patient who underwent David I procedure. Segmentation and measurement of the geometric parameters of the aortic root were performed before operation, as well as 18 months after surgical treatment. To assess the function of the reimplanted aortic valve during the long-term follow-up, a detailed echocardiographic assessment was used. Echocardiographic assessment included measuring volume and area of the regurgitation flow, the width of vena contracta, and the regurgitation fraction. The application of high-precision 3D reconstruction opens up additional opportunities in the field of surgical treatment of the aortic root and AV pathology: advantages in choosing an individual patient-oriented surgical tactics, parameters of the implanted surgical material and/or device, and in predicting long-term results of surgical treatment.

Using Virtual Reality Technology in the Design of Complex Systems

This article provides a concrete example for using and creating a virtual environment for computer-aided design of complex systems. The subject area is design, and the object of research is an aircraft. CAD creates a parameterized 3D model, which is demonstrated and processed on a virtual stage using special equipment. Special equipment such as the HTC Vive Pro virtual reality helmet and the included controllers. The virtual assistant of the designer allows you to create detailed parameterized models of an aircraft, in particular, a transport aircraft based on the An-124 Ruslan, and virtual reality helps the user to learn more about the created project and make the necessary optimization edits directly in VR space. By changing the model in VR space, it will change in the main project. The work is a continuation of the development of a decision-making system, a virtual assistant to the designer: "Robot designer", whose application interface has been defined. The main control menu for the user in virtual space is shown, and the aircraft with the fuselage skin and cockpit removed is also shown. Plans for further use of virtual reality technology in the design of complex systems and training of specialists with the profile of aircraft engineers are presented.

High-precision computer segmentation of the aortic valve and aortic root

Background. Valve-sparing aortic root replacement with aortic valve reimplantation is a rapidly developing method of treatment of ascending aortic aneurysm. The improvement of the results of this method is inextricably linked with the understanding of the relationships between the initial functional and planimetric characteristics of the valvular-aortic complex, the technical aspects of the reimplantation procedure and the results obtained.Objective. To search and analyze previously little-studied factors — the planimetric characteristics of the aortic valve and the aortic root.Design and methods. High-precision assessment of the planimetry of the aortic flaps requires precision visualization methods and subsequent creation of virtual three-dimensional models. The creation of high-precision reconstructions became possible due to the introduction of specialized computer-aided design environments into clinical practice. Due to the technical complexity, none of the known methods has previously been used to accurately measure all the structures of the aortic root in a large group of patients. Simplification, acceleration of reconstruction construction, as well as scaling of this technique remain unresolved tasks.Results. The main result of this work is the development of an algorithm of segmentation of the aortic root and the construction of a high-precision three-dimensional model of the aortic valve, as well as the practical implementation of an algorithm for determining main planimetric parameters of the aortic root with the possibility of scaling to a large group of patients.Conclusion. The method makes it possible to construct a high-precision three-dimensional reconstruction of the internal structures of the aortic root within a few hours and is valuable both for determining the tactics and technical features of surgical treatment of the patient, and for studying the effect of the anatomy of the aortic root on the development of recurrence of aortic insufficiency after valve-sparing surgery.

Declining neighborhood simulated annealing algorithm to robust fixture synthesis in a point-set domain

Fixture synthesis addresses the problem of fixture-elements placement on the workpiece surfaces. This article presents a novel variant of the simulated annealing (SA) algorithm called declining neighborhood simulated annealing (DNSA) specifically developed for the problem of fixture synthesis. The objective is to minimize measurement errors in the machined features induced by the misalignment at locators-workpiece contact points. The algorithm systematically evaluates different fixture layouts to reach a sufficient approximation of the most robust layout. For each iteration, a set of previously accepted candidates are exploited to direct the search toward the optimal region. Throughout the progress of the algorithm, the search space is reduced and the new candidates are designated according to a declining probability density function (PDF). To assure best performance, the DNSA parameters are configured using the Technique for Order Preference by Similarity to Ideal Solution (TOPOSIS). Moreover, the parameters are set to auto-adapt the complexity of a given input based on a Shanon entropy index. The optimization process is carried out automatically in the computer-aided design (CAD) environment NX; a computer code was developed for this purpose using the application programming interface (API) NXOpen. Benchmark examples from industrial partner and literature demonstrate satisfactory results.

Point of Care Virtual Surgical Planning and Three-Dimensional Printing for Feminizing Foreheadplasty.

Point of Care Virtual Surgical Planning and Three-Dimensional Printing for Feminizing Foreheadplasty.