Created 3D Models Research Articles

Technological Aspects of using 3D Printing Software in Construction

The relevance of introducing additive technologies of 3D printing in construction is to decrease the technological cycle of construction, and minimize expenditure and material costs, while reducing the duration of the development planning process and execution, eliminating inaccuracies and defects, as well as optimizing and automate the process. The technological aspect of 3D printing lies in the optimal selection of parameters based on the created 3D model using effective software. The purpose of the study is to determine the quality indicators of bricks obtained by 3D printing from special concrete. The approach to investigating this matter is rooted in ascertaining the compressive strength of concrete through non-invasive testing techniques, gauging the density of concrete using measurement methods, and validating the efficacy of integrating 3D printing technologies in construction by the method of comparative analysis. The effectiveness of introducing additive technologies of 3D printing was proven drawing upon quality indicators of concrete obtained on a 3D printer which meets all the requirements necessary for its implementation in the construction field. The selected characteristics of concrete compressive strength are fundamental to the basics of selecting a brand of concrete to be utilized in construction. The selected software demonstrated the capacity to generate flawless 3D designs. The result of the study shows a significant reduction in the number of workers involved in the construction process by 38–45%, depending on the chosen method of using 3D printing; a decrease of construction time by 33–42% when printing individual elements, blocks used in production, and by 61–72% when using a printer directly on the construction site; reduction of raw materials costs by 14–28%; as well as reduction of construction downtime by 25%. The results obtained indicate the need to develop and enhance progressive additive technologies for 3D printing in construction.

STUDY OF HEAT AND MASS TRANSFER IN WOOD-COMPOSITE MATERIALS BY MEANS OF COMPUTATIONAL FLUID DYNAMICS

Wood-composite materials (WCM), undergoes complex heat and mass transfer processes during its conditioning. Understanding these interactions is crucial for optimizing the conditioning process and ensuring high quality of the final product. This study focuses on the problem of modeling the interactions that occur during WCM conditioning, taking into account their characteristics that depend on temperature, moisture content, and density of the material. In addition, various input parameters are taken into account in the modeling process to set the optimal conditioning conditions. Despite the availability of these parameters in the literature based on the results of real experiments, consolidating this data in computer modeling is still a major problem. To resolve this issue, this study focuses on modeling the heat and mass transfer processes during WCM cooling using computational fluid dynamics (CFD) software such as SolidWorks Flow Simulation. By using the capabilities of CFD, it is relatively possible to utilize technical parameters involved in the WCM conditioning process with relative simplicity. The paper provides a detailed description of the created 3D model of the WCM-conditioning chamber and its main components. In addition, the paper describes the various input parameters used in the modeling process, including temperature, moisture content, and density of WCM. In addition, the operation of the fans was set up and the initial values of temperature, moisture content, and air velocity were set. Based on the simulation, the results obtained include the distribution of the temperature field and moisture content on the surface of the WCM at different material densities and air conditioning parameters. Additionally, the trajectory of air masses and their velocity within the 3D model was obtained. In general, the obtained results provide a better understanding of the influence of various input parameters on the process of heat and mass transfer in WCM during their cooling. Given the comprehensive analysis, this research this work can be useful for improvement of WCM production processes and quality control of final products. In particular, it emphasizes the importance of further research in this area and the need for computer modeling of such processes to further develop effective engineering solutions.

Automatic generation of pipelines from 2D CAD drawings to 3D IFC models using a parametric method

Creating 3D models of pipelines is essential for effective digital building management. However, generating 3D pipeline models from 2D CAD drawings still heavily depends on human-computer interaction at the design stage. This paper addresses this challenge by proposing a method to generate parametric 3D pipeline models from CAD drawings automatically. The framework includes three parts. Firstly, automatic layer recognition algorithms are used to extract data from CAD drawings, and algorithms are designed to match pipeline coordinates and diameters. Then, data on straight pipes is processed, including judging types of pipe fittings and calculating relevant parameters to realize the automatic generation of 3D BIM models. Finally, IFC is utilized to express the geometry and topology of models for BIM model generation. The process is implemented by writing a C++ program in Visio Studio 2019. Experimental results on a building water supply and drainage system demonstrate that the proposed method can significantly improve the generation efficiency and automation level of pipeline models.

Cost-effective 3D documentation device in forensic medicine

3D documentation in forensics and forensic medicine is being introduced more frequently in various institutes around the world. However, several institutes lack capacity in finances as well as staff to perform 3D documentations regularly. This technical paper aims to present a 3D documentation device that is low cost and easy to use and is a viable entry level solution for forensic medical departments. For this the small single-board computer Raspberry Pi 4 was used in conjunction with its high quality (HQ) camera module to create the 3DLamp - a flexible, low cost and easy to use documentation device. Besides a detailed description of the device this paper also presents four case examples where a 3D documentation was performed and analyses the acquired data and the created 3D models. It was found that the device returns feasible 3D models that appear usable for forensic 3D reconstructions.

Modeling of a Public Utility Facility from Total BIM Data

The purpose of this work is to present the possibilities of using tacheometric measurement technology in the development of a 3D geometric model of an existing building and the directions of using BIM technology in the process of building operation. General information on the development of BIM technology was presented, and issues related to the construction of 3D models were discussed. Attention was also drawn to the need to update the information assigned to the model on an ongoing basis in order to effectively manage the building. Supplementing the model with metadata regarding the building materials used will allow for a precise and quick analysis of all renovation assumptions. The created 3D model can be used to control the condition of structures or in safety and risk management.

Inferring implicit 3D representations from human figures on pictorial maps

ABSTRACT In this work, we present an automated workflow to bring human figures, one of the most frequently appearing entities on pictorial maps, to the third dimension. Our workflow is based on training data and neural networks for single-view 3D reconstruction of real humans from photos. We first let a network consisting of fully connected layers estimate the depth coordinate of 2D pose points. The gained 3D pose points are inputted together with 2D masks of body parts into a deep implicit surface network to infer 3D signed distance fields (SDFs). By assembling all body parts, we derive 2D depth images and body part masks of the whole figure for different views, which are fed into a fully convolutional network to predict UV images. These UV images and the texture for the given perspective are inserted into a generative network to inpaint the textures for the other views. The textures are enhanced by a cartoonization network and facial details are resynthesized by an autoencoder. Finally, the generated textures are assigned to the inferred body parts in a ray marcher. We test our workflow with 12 pictorial human figures after having validated several network configurations. The created 3D models look generally promising, especially when considering the challenges of silhouette-based 3D recovery and real-time rendering of the implicit SDFs. Further improvement is needed to reduce gaps between the body parts and to add pictorial details to the textures. Overall, the constructed figures may be used for animation and storytelling in digital 3D maps.

Analysis of Heavy Motor Vehicle Chassis Frame with Different Materials Equipped with CNG Cylinders of Composite Materials Using CAE Tools

Abstract: The transport sector now has a significant impact on both the economies of developed and developing nations The frame, also known as the chassis, is the main part of the vehicle because it has the highest design stress. This is vehicle support as all components are only supported on the chassis. Using the chassis as a platform, the front and rear suspensions are connected without dropping. At the same time, it can also be used for sudden stops, bumpy roads, and high-speed driving. It has sufficient rigidity to withstand impact, deflection, bending, vibration and shape deformation caused by causes. Scientific data obtained from various studies to date, weight, stress and strength, deformation, etc. have proven to be ideal for many factors. This can be done by changing the section and material of the chassis frame. The material chosen for this project is AISI4130 for LPO 1613 CNG BS-IV OBDII Front Engine Bus for Delhi Integrated Intermodal Transport System (DIMTS). Create 3D models in CAE Solid-works and analyze them with ANSYS 19.2. Automotive composite CNG cylinders are the best combination of the latest technology using carbon fiber reinforced seamless aluminum inner liner

Use of 3D Inferred Imagining for Detection of Changes in Geology in Longwall-Type Excavation Front

In this paper, I will show and describe a method of integrating infrared images with a 3D model of the front of an excavation in the longwall type of workings. I will also test the created 3D model for its potential usefulness in geological prospecting, used for looking for changes in geological layout at the front of the excavation. Geological information on the amount of coal in the front is important for the economic side of the excavation. The mine does not want to take out waste rock, but mostly for the safety of operations. The longwall shearers and plows are not designed for excavation in extremely changeable conditions, so if too much shale appears, this might change the speed and economic results of excavation. In addition, if a fold appears, this can destroy the excavating complex. Currently, the geological survey requires a geologist to get to the front, often to the unsupported roof part of the wall, clean the front and sample, and measure the geology. This is dangerous for the geologist. Thus, remote, infrared measurements would improve the safety of the staff and allow the survey to be taken in more places along the longwall. In this paper, I will also propose how such a system could be implemented and what the limitations are.

Организация практико-ориентированного обучения на кафедре «Инженерная графика» РТУ МИРЭА

The article discusses the organization of practice-oriented learning at the Department of Engineering Graphics of the RTU MIREA, the essence of which is the development of not only design documentation, but also the production of a prototype device for which design documentation has been made. Geoinformatics students create 3D models of terrain objects: buildings, terrain and vegetation based on photo and video data from drones. The course project serves as the basis for a deeper study of geometric and graphic disciplines in the form of competitive works, scientific reports and publications, or can serve as the basis for the final qualification work.
 As part of the course work, students of the Institute of Radio Electronics and Informatics perform a multi-level study of an electronic device - a sensor using "smart home" technology. Not only a significant amount of design documentation is developed with the help of circuitry and design CAD: diagrams, printed circuit boards with tracing, assembly drawings, specifications and other text documents, but also a working prototype of the sensor is made.
 As part of the course work, chemists-technologists design a workshop for large- and medium-tonnage chemical production and develop a complete set of design documentation for one of the main apparatuses of this workshop. Based on the created 3D models, students print a model of the apparatus on a 3D printer.
 As part of the "Fundamentals of Design" course, some students develop design documentation and make one of the two printed circuit boards of a dog robot based on it. Another part of the students creates 3D models of robot parts and prints them on a 3D printer. Both groups jointly assemble and program a robot dog.

3D Visualisation of the Historic Pre-Dam Vltava River Valley—Procedural and CAD Modelling, Online Publishing and Virtual Reality

As a part of “The Vltava River” project, it was necessary to create a visualisation of the historic Vltava River valley before the construction of the so-called Vltava Cascade (nine dams built in the Vltava River basin between 1930 and 1992). Vectorisations of the Imperial Obligatory Imprints of the Stable Cadastre, and a terrain model created from contour lines from the State Map 1:5000-Derived (SMO-5), prepared in an earlier phase of the project, were used as a basis for this visualisation. Due to the extent of the modelled area, which is approximately 1670 km2, and the available underlying data realistically usable for the visualisation, mainly procedural modelling with the use of the CGA shape grammar was chosen for the creation of 3D objects. These procedurally created 3D models were completed with more detailed models of landmark buildings created in CAD. The outcomes were used to establish a virtual reality (VR) application in the Unreal Engine software. The results are a 3D scene created in a form corresponding approximately to the state of the Vltava River valley in the 19th century, which is available for viewing via a web application, and a VR scene used for demonstration at exhibitions.

ДЕЯКІ ОСОБЛИВОСТІ РОБОТИ З ПАКЕТОМ 3DMAX

The paper proposes an approach to creating 3d models without errors arising in connection with the use of special mathematical software of this package.

Continuing the Legacy of Grant’s Museum: Anatomy Education in the Digital Era

IntroductionIn the 1930s, an innovative adjunct available to anatomy learners was Grant’s Atlas of Anatomy and Grant’s Museum specimens of regional anatomy. With advancements in technology, learning tools used in anatomy education now also include digital reproductions of cadaveric specimens into 3D or interactive formats. Recent pivoting to online teaching and increased reliance on digital resources makes it a natural progression to advance the legacy of Grant's work with an online library of 3D models matching the museum. Realistic digital models are typically produced by either 3D reconstruction from image data, or photogrammetry, both requiring technical skill and time. Recent advances in light technology scanning equipment like the Artec Space Spider claim to produce a high‐fidelity 3D model within a time frame of 2‐3 hours from scan to finished digital model using their bundled software. In an ongoing project creating 3D models from prosections reproducing Grant’s Museum, we aimed to determine the efficiency of digital capture and the final model fidelity using the Artec Space Spider scanner.MethodsTwenty‐seven prosections were created to replicate 38 figures in Grant’s Atlas, ranging from simple geometries such as a lung, to more complex, including the posterior abdominal wall.Scanning & post‐processing: Prosections were scanned using the Artec Space Spider, which captured images at around 7.5 frames per second (0.1 mm resolution). Post‐processing was completed in Artec Studio (Artec Studio 15 Professional x64 15.1.2.60) including alignment, hole‐filling and texture overlay. Early on, it was determined that many models needed digital sculpting, so we engaged expert digital artists using software (Zbrush 2021.6.6) for refinement of the models. The amount of time it took to scan and process each model was calculated to determine efficiency of model development.Fidelity confirmation: Ongoing feedback is being collected from an expert panel of anatomists representing five post‐secondary institutions. These experts are provided finished digital models and feedback is collected on the aspects of texture, lighting, anatomical detail (resolution) and model manipulation (user tools for examining online). This feedback will be finalized in February 2022.ResultsTable 1 depicts the breakdown of scanning and post‐processing time. Forty percent of the models were completed in under 3 hours, and these included prosections with simple geometries. Sixty percent of the models took more than 3 hours to complete, and these included more intricate prosections.ConclusionsWhile the Artec Space Spider may be a great tool to quickly generate anatomical models with simple geometry or features, it may not be ideal for replicating intricate anatomical prosections. Only 40% of scans took less than 3 hours to complete with most moderately complex models and all complex models taking over 3 hours. Much of the time spent on these models was in post‐processing, which was dedicated to filling gaps or refining the details of the models. Our findings suggest that the time:cost ratio may not justify the purchase of such high‐level technology when photogrammetry may result in similar models for relatively less investment.

Forensic examination of living persons in 3D models

Physical injuries caused by interpersonal violence or accidents are usually documented with photographs. In addition to standard injury photography using 2D photographs, the Institute *INSTITUT NAME BLINDED FOR REVIEW* uses a Botspot Botscan ® multi-camera device (Photobox; Aniwaa Ltd, Berlin, Germany) that allows for 3D documentation of a subject. The Photobox contains 70 cameras positioned at different heights looking at a central platform. Within a fraction of a second, all cameras are activated and acquire the necessary images for 3D documentation. In previous studies by Michienzi et al. (2018), the geometric correctness of 3D documented injuries was analyzed. While their work concentrated solely on artificial injuries and their dimensions, the work presented in this study analyzes whether the Photobox allows for accurate medical interpretation of injuries, by forensic pathologists. To perform this analysis, 40 datasets of a variety of real cases were processed to 3D models. The created 3D models were then examined by forensic pathologists on 2D computer screens, and the findings were compared with the original reports. While the aim of this work was to assess whether examinations based on a 3D model allows comparable results to immediate examinations of the subject, the results showed that examinations based on a 3D model are 85% accurate when comparing with physical examinations. This indicates that 3D models allow for reasonably accurate interpretation, and it is possible that accuracy might increase with improved equipment and better trained personnel.

3D multimodal teaching of human anatomy and autopsy with real human data

With advances in digitalization, the industrial, education, and research sectors have made use of novel methods to train their staff and students. Simulations and visualizations of real-life situations allow effective and tailored learning strategies. In medicine, the advancement of three-dimensional (3D) surface documentation technologies, particularly close-range photogrammetry, are used to document pathologies or procedural steps in 3D. Subsequently created 3D models enhanced by adding annotations, incision lines, explanations, and animations can be used for educational purposes. In this paper, we describe possible ways to improve or extend actual learning methods in medical teaching and show a concept for possible application. As various teaching tools already exist, we aim to add a teaching approach using 3D visualization. Therefore, a forensic dissection of the neck was documented in 3D, annotated and prepared for teaching using animated videos, 3D PDFs and virtual reality. In the future, the dissection of each body part and organ will be documented using the procedure presented in this paper. The aim of this method is to provide a technique to teach human anatomy and autopsy steps to both medical students and forensic pathologists.

Експериментальне дослідження універсальної будівельної вібромашини широкого застосування

Experimental studies of the efficiency of the method of excitation of resonant vibrations by passive autobalancers for a single-mass vibrating machine with translational rectilinear motion of the vibrating platform have been carried out. A vibrating machine with a platform size of 1000x600 mm has been designed, in which a ball balancer is used as a vibrating exciter. The vibrating machine can work in 2 two modes: the first - a vibrating sieve; the second is a vibrating table. The difference between the modes is the different amplitudes and frequencies of the working surface. According to the technical recommendations, Solidworks CAD created a 3D model of a single-mass vibrating machine with a vibrating exciter in the form of a ball autobalancer using the Cosmos Motion module. After checking the performance of the created 3D model, the optimal parameters were selected and an industrial design of the vibrating machine (an exact copy of the 3D model) was created. Before the experiments, a dynamic balancing of the shaft with the autobalancer assembly without balls in their own supports was performed. After checking the quality of balancing, the straightness of the platform was checked. Balls in the autobalancer were removed. 4 checkpoints were applied to the working surface of the platform. An electric motor with a speed of 25 Hz was started. Then with the help of the device "Beam 4" at each point simultaneously measured the value of vibration velocities. As a result of checking the straightness of the platform, it was found that the difference between the values of measurements at different points does not exceed 25%. This indicates the straightness of the movement of all points of the working surface of the platform and, accordingly, the sieve. An electric motor with a speed of 50 Hz was started. Using a vibrometer "Walcom" WM6360 were measured values of movement of the working surface of the table. Then the selection of the unbalanced mass was performed at which the oscillation range of the platform corresponded to the standard values of industrial vibrating machines. Then the platform was loaded with a load of 25 kg, 55 kg and the experiment was repeated. A series of experiments to determine the main characteristics of the developed design of the vibrating machine in the mode of vibrating table and vibrating screen. The energy efficiency of the proposed design of the vibrator was also tested. Measurements of electric energy consumption at different speeds and with different vibrators are performed. As a result of experimental studies, it was found that compared to a conventional inertial vibrating machine, the new machine has 15-25% higher productivity with 10-40% lower energy consumption. The unbalanced masses in the new vibrator are 4-6 times less than the unbalanced masses in the conventional inertial vibrator.

РАЗРАБОТКА ВИРТУАЛЬНОГО ПРОИЗВОДСТВА НА ПРИМЕРЕ УЗЛА РАЗДЕЛЕНИЯ ПЕНТАН-ГЕКСАНОВОЙ ФРАКЦИИ

Relevance The development of the educational process in educational institutions and enterprises requires appropriate improvement of computer training systems. For the training of highly professional personnel, the development of high-tech computer simulators using modern virtual reality technologies is required. AR and VR are a direction which popularity is growing from year to year. Today, almost every company is interested in applications using these technologies. From Oculus to MSQRD, from simple apps that project various toys in the room to IKEA view apps and more and so on. There are a huge variety of application options. But there is also not the most popular in comparison with them, but in fact a useful area – teaching a person new skills and simplifying his daily work. Here, as an example, we can cite simulators for doctors, pilots and even law enforcement agencies. Chemical and petrochemical enterprises are implementing these technologies as part of the digitalization of production. The main consumer is a direct employee of the production in gloves and a helmet, who is at the enterprise, at high-risk objects. The concept of «Industry 4.0» is becoming increasingly popular, the fourth industrial revolution is the unification of industry and digital technologies, leading to the creation of digital production facilities or smart factories and factories. In Europe, this concept is considered to be everything related to digital technologies in the enterprise in a general sense. In Russia, 4.0 is digital products that are somehow connected with hardware. First of all, of course, this is the industrial Internet of Things (IIoT), plus a direction related to video analytics, and also a direction called XR (AR + VR). The main task of IIoT is to increase the level of automation in production, reduce the influence of the human factor on the process of managing non-critical technological processes, and reduce the cost of equipment operation. Virtual reality is a model of the surrounding world, artificially created with the help of technical means and presented in digital form. The created effects are projected onto the human consciousness and allow you to experience sensations that are as close to real as possible. The analogues that exist today, developed by large design institutes and companies, have limited access and high cost. The virtual petrochemical production developed within the framework of this project should be a software product containing a production site as close as possible to the real one: technological equipment – columns, heat exchangers, tanks, facilities – pumps, compressors, pipelines, control valves, valves, sensors and actuators. The user, wearing virtual reality glasses and picking up controllers, will have the opportunity to take a tour of the developed production site. The visual series should almost completely correspond to reality, but some details that do not affect the learning process can be simplified so as not to spend a lot of time reproducing them. The use of sound effects that simulate the real sounds of this production will complement the effect of immersion in a virtual reality environment. Aim of research Transfer of the production process of the pentane-hexane fraction separation unit to a virtual reality environment. Methods To create 3d models of the necessary technological equipment, machines, devices, etc., the Autodesk 3ds Max 2015 program was used. Unreal Engine 4 was used to collect the created models into a single scene, as well as to write code for interacting with the virtual reality environment. Results This article discusses the creation of a model of the production process of the pentanehexane fraction separation unit in a virtual reality environment in order to monitor the progress of the technological process and control it through the objects of this production.

Effects of zinc-containing diamond-like carbon coated splints on the healing of fractures in mice: A pilot study

Diamond-like carbon (DLC) coatings are highly biocompatible. They have been attracting attention because they can be used in the surface treatment of body-implanted devices. Zinc (Zn) promotes the metabolism of skin and bones. For these reasons, we developed Zn-doped DLC (Zn-DLC), a highly biocompatible DLC, as a coating material to promote bone formation. In our previous study, in vitro tests using osteoblast cells revealed that Zn-DLC promoted calcification associated with osteogenesis. Therefore, in the present study, the ability of Zn-DLC to promote osteogenesis was assessed in vivo using a Zn-deficient mouse model.We compared the healing stages of the bone fractures between Zn-DLC splints group and DLC splints group (N = 7 mice in each group), using computed tomography (CT)-created 3D models of the fractured parts. The number of mice that were fully healed by 4 weeks when fixed with DLC and Zn-DLC splints was two and four, respectively. Then, we investigated the bone features (the bone volume, bending strength, twisting strength, cortical bone thickness, cortical bone area ratio, and spongiosa bone density) after the in vivo test. These results suggested that Zn-DLC had tendencies to improve these parameters compared with DLC, though these differences were not significant statistically. Moreover, we confirmed Zn elution from Zn-DLC, using XPS analysis.These results suggested that Zn-DLC can supply Zn in vivo condition and may improve the therapeutic effect of conventional implants used in the treatment of fractures.

Classification and Change Detection in Mobile Mapping LiDAR Point Clouds

Creating 3D models of the static environment is an important task for the advancement of driver assistance systems and autonomous driving. In this work, a static reference map is created from a Mobile Mapping “light detection and ranging” (LiDAR) dataset. The data was obtained in 14 measurement runs from March to October 2017 in Hannover and consists in total of about 15 billion points. The point cloud data are first segmented by region growing and then processed by a random forest classification, which divides the segments into the five static classes (“facade”, “pole”, “fence”, “traffic sign”, and “vegetation”) and three dynamic classes (“vehicle”, “bicycle”, “person”) with an overall accuracy of 94%. All static objects are entered into a voxel grid, to compare different measurement epochs directly. In the next step, the classified voxels are combined with the result of a visibility analysis. Therefore, we use a ray tracing algorithm to detect traversed voxels and differentiate between empty space and occlusion. Each voxel is classified as suitable for the static reference map or not by its object class and its occupation state during different epochs. Thereby, we avoid to eliminate static voxels which were occluded in some of the measurement runs (e.g. parts of a building occluded by a tree). However, segments that are only temporarily present and connected to static objects, such as scaffolds or awnings on buildings, are not included in the reference map. Overall, the combination of the classification with the subsequent entry of the classes into a voxel grid provides good and useful results that can be updated by including new measurement data.

Methodology for numerical modeling of the sowing apparatus of a small-seeded crop selection seeder

The article describes the methodology for numerical modeling of the process of sowing seed material of small-seeded crops in the STAR-CCM+ software package based on the created 3D model of the sowing machine and the accepted physical models. The boundary and initial conditions of the simulation are presented. To verify the created simulation of the developed sowing apparatus of the breeding seeder, a visualization of the process of its operation was obtained and the dynamics of quantitative seed consumption was determined. The average value of quantitative seed consumption and its standard deviation were calculated. It is substantiated that for further research, the following factors were chosen as research factors: the manufacture of a cylindrical metering device (I - triangle, II - semicircle, III - rectangle), the angle of rotation of the flap α, the time interval when the flap is open or closed Δt, the speed of movement of the seeder V.

РЕШЕНИЕ ОБРАТНОЙ ЗАДАЧИ НАХОЖДЕНИЯ ПОВЕРХНОСТНОЙ ПЛОТНОСТИ ЗАРЯДА ПО ИЗВЕСТНОМУ ЭЛЕКТРИЧЕСКОМУ ПОТЕНЦИАЛУ СРЕДСТВАМИ COMSOL MULTIPHYSICS

Relevance Polymer materials capable of electric charge accumulation on their surface and in volume have wide application in a great number of applied problems of electrophysics and high-voltage engineering due to their excellent dielectric property. This property can be both an advantage (in electret manufacture), and a disadvantage (when using polymers as an isolating medium). Fundamentally important here is the need to characterize and control the degree of charge using the value of surface charge density which, however, can be determined indirectly through the electric potential only. When measuring the potential using a capacitive probe, difficulties arise in solving an inverse problem of converting the potential into surface charge density, since the relationship between these values largely depends on the geometry of the charged body and the capacitive probe. An effective and universal conversion method will greatly simplify the measurement of the surface charge density that will be helpful in practical tasks of electrical technology and operation of high-voltage equipment with elements made of polymer materials. Aim of research Aim of the research is to develop a technique for restoring surface charge density distribution according to a given measured distribution of electric potential created by the surface charge; give recommendations on how to achieve an optimal balance between accuracy and labor intensity of numerical calculations. Methods The problem is solved using numerical modeling in finite element method based software Comsol Multiphysics. With the help of the created 3D model containing the reproduced design of the capacitive probe and the charged examined material, the principle of the weight coefficients matrix formation is explained, through which the relationship between a discrete set of measured potentials and the unknown distribution of the surface charge density is subsequently established. Results An effective method has been developed to recalculate the known distribution of the electric potential from a charged surface into its surface charge density. The principle of constructing and setting the boundary conditions in the 3D model required for recalculation is shown. On the example of one given distribution of electric potential, the high efficiency of the method for obtaining the distribution of the charge density was shown. It has been established that the accuracy of the method increases with a finer partition of the charged surface into elementary charged areas. Recommendations are given on the use of methods for solving the arising systems of linear algebraic equations. It was also shown how to simplify the technique used in the presence of an axisymmetric distribution of the charge density.