Nauki Techniczne

Bulletin of the Polish Academy of Sciences Technical Sciences

Zawartość

Bulletin of the Polish Academy of Sciences Technical Sciences | 2023 | 71 | 3

Autorzy i Afiliacje

Jan Holnicki-Szulc
1
ORCID: ORCID
David Wagg
2
ORCID: ORCID
Fabio Casciati
3
ORCID: ORCID
Lucia Faravelli
3
ORCID: ORCID
Łukasz Jankowski
1
ORCID: ORCID

  1. Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
  2. University of Sheffield, Sheffield, United Kingdom
  3. Zhejiang University, Hangzhou, China

Abstrakt

Reducing the effect of unwanted vibrations is an important topic in many engineering applications. In this paper we describe some recent developments in the area of passive vibration mitigation. This is based on a new device called the inerter which can be exploited in a range of different contexts. In this paper we consider two recent examples; (i) where a flywheel inerter is combined with a hysteretic damper, and (ii) in which a pivoted bar inerter is developed for a machining application. In both cases, experimental test results show that the devices can outperform existing methods.
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Autorzy i Afiliacje

David J. Wagg
1
ORCID: ORCID

  1. Department of Mechanical Engineering, University of Sheffield, Sheffield, United Kingdom

Abstrakt

The paper concerns the optimization of a tuned mass damper with inerter (TMDI) based on two strategies, i.e., the minimum amplitude in the resonance peak and minimum area under the frequency response curve. The optimization is based on real, accessible parameters. Both optimization procedures are presented in two steps. In the first one, two parameters of the TMDI are tuned (inertance and damping coefficient), while in the second one, three parameters (mass, inertance, and damping coefficient). We show that both strategies give the optimum sets of parameters and allow the reduction of the amplitude of the damped system.
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Autorzy i Afiliacje

Konrad Mnich
1
Przemysław Perlikowski
1
ORCID: ORCID

  1. Division of Dynamics, Lodz University of Technology, Stefanowskiego 1/15, 90-924 Lodz, Poland

Abstrakt

This paper presents the experimental results of a new proof mass actuator for the implementation of velocity feedback control loops to reduce the flexural vibration of a thin plate structure. Classical proof mass actuators are formed by coil–magnet linear motors. These actuators can generate constant force at frequencies above the fundamental resonance frequency of the spring–magnet system, which can be used to efficiently implement point velocity feedback control loops. However, the dynamics of the spring–magnet system limit the stability and control performance of the loops when the actuators are exposed to shocks. The proof mass actuator investigated in this paper includes an additional flywheel element that improves the stability of the velocity feedback loop both by increasing the feedback gain margin and by reducing the fundamental resonance frequency of the actuator. This paper is focused on the stability and control performance of decentralized velocity feedback control loops.
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Autorzy i Afiliacje

Aleksander Kras
1
ORCID: ORCID
Paolo Gardonio
2
ORCID: ORCID

  1. Silencions, Bierutowska 57-59, 51-315 Wrocław, Poland
  2. DPIA, Università di Udine, Via delle Scienze 206, 33100, Udine, Italy

Abstrakt

The structural concept of the dome dates back to the Pantheon in Rome. It is used as the cover of many churches and mosques all around the world. Light solutions, with a well-visible dome-shaped truss skeleton, are often preferred in modern architecture. Base isolation techniques can be adopted to mitigate the seismic effects. This paper aims to investigate the efficiency of different designs for the truss skeleton. To solve the problem, one has to assign the constraints, the materials and the geometry of the dome, its supporting structure and the isolation devices (number, locations, and type). The screening of the effects of different scheme assumptions on structural behaviour provides a better insight into the problem.
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Autorzy i Afiliacje

Sara Casciati
1
ORCID: ORCID

  1. SIART srl, Pavia, Italy

Abstrakt

An iterative neural network framework is proposed in this paper for the human-induced Ground Reaction Forces (GRF) replication with an inertial electrodynamic mass actuator (APS 400). This is a first approach to the systematization of dynamic load tests on structures in a purely objective, repeatable and pedestrian-independent basis. Therefore, an inversion-free offline algorithm based on Machine Learning techniques has been applied for the first time on an electrodynamic shaker, without requiring its inverse model to tackle the inverse problem of successful force reconstruction. The proposed approach aims to obtain the optimal drive signal to minimize the error between the experimental shaker output and the reference force signal, measured with a pair of instrumented insoles (Loadsol©) for human bouncing at different fre- quencies and amplitudes. The optimal performance, stability and convergence of the system are verified through experimental tests, achieving excellent results in both time and frequency domain.
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Autorzy i Afiliacje

César Peláez-Rodríguez
1 2
ORCID: ORCID
Álvaro Magdaleno
2
Sancho Salcedo-Sanz
1
Antolín Lorenzana
2

  1. Department of Signal Processing and Communications, Universidad de Alcalá, Alcalá de Henares, 28805, Spain
  2. ITAP. Escuela de Ingenierías Industriales. Universidad de Valladolid. P.º del Cauce, 59, 47011 Valladolid, Spain

Abstrakt

The condition monitoring of offshore wind power plants is an important topic that remains open. This monitoring aims to lower the maintenance cost of these plants. One of the main components of the wind power plant is the wind turbine foundation. This study describes a data-driven structural damage classification methodology applied in a wind turbine foundation. A vibration response was captured in the structure using an accelerometer network. After arranging the obtained data, a feature vector of 58 008 features was obtained. An ensemble approach of feature extraction methods was applied to obtain a new set of features. Principal Component Analysis (PCA) and Laplacian eigenmaps were used as dimensionality reduction methods, each one separately. The union of these new features is used to create a reduced feature matrix. The reduced feature matrix is used as input to train an Extreme Gradient Boosting (XGBoost) machine learning-based classification model. Four different damage scenarios were applied in the structure. Therefore, considering the healthy structure, there were 5 classes in total that were correctly classified. Five-fold cross validation is used to obtain a final classification accuracy. As a result, 100% of classification accuracy was obtained after applying the developed damage classification methodology in a wind-turbine offshore jacket-type foundation benchmark structure.
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Autorzy i Afiliacje

Jersson X. Leon-Medina
1 2
ORCID: ORCID
Núria Parés
3
ORCID: ORCID
Maribel Anaya
4
ORCID: ORCID
Diego A. Tibaduiza
4
ORCID: ORCID
Francesc Pozo
1 5
ORCID: ORCID

  1. Control, Data, and Artificial Intelligence (CoDAlab), Department of Mathematics, Escola d’Enginyeria de Barcelona Est (EEBE),Campus Diagonal-Besòs (CDB), Universitat Politècnica de Catalunya (UPC), Eduard Maristany 16, 08019 Barcelona, Spain
  2. Programa de Ingeniería Mecatrónica, Universidad de San Buenaventura, Carrera 8H #172-20, Bogota, Colombia
  3. Laboratori de Càlcul Numèric (LaCàN), Department of Mathematics, Escola d’Enginyeria de Barcelona Est (EEBE), Campus Diagonal-Besòs
  4. Departamento de Ingeniería Eléctrica y Electrónica, Universidad Nacional de Colombia, Cra 45 No. 26-85, Bogotá 111321, Colombia
  5. Institute of Mathematics (IMTech), Universitat Politècnica de Catalunya (UPC), Pau Gargallo 14, 08028 Barcelona, Spain

Abstrakt

Early detection of damage is necessary for the safe and reliable use of civil engineering structures made of concrete. Recently, the identification of micro-cracks in concrete has become an area of growing interest, especially when it comes to using wave-based techniques. In this paper, a non-destructive testing approach for the characterization of the fracture process was presented. Experimental tests were performed on concrete beams subjected to mechanical degradation in a 3-point bending test. Ultrasonic waves were registered on a specimen surface by piezoelectric transducers located at several points. Then, the signals were processed taking advantage of wave scattering due to micro-crack disturbances. For early-stage damage detection, coda wave interferometry was used. The novelty of the work concerns the application of the complex decorrelation matrix and the moving reference trace approach for better distinguishment of sensors located in different parts of a crack zone. To enhance coda wave-based damage identification results, optical imaging of crack development was performed by means of digital image correlation measurement. The results obtained showed that the coda wave interferometry technique can be successfully used as a quantitative measure of changes in the structure of concrete. The results also indicated that the course of decorrelation coefficient curves enabled the identification of three stages during degradation, and it depended on the location of acquisition points versus the crack zone.
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Autorzy i Afiliacje

Magdalena Knak
1
ORCID: ORCID
Erwin Wojtczak
1
ORCID: ORCID
Magdalena Rucka
1
ORCID: ORCID

  1. Department of Mechanics of Materials and Structures, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology,Narutowicza 11/12, 80-233, Gdańsk, Poland

Abstrakt

It is highly important to determine eigenvalues before and after certain extreme events that may cause damage accumulation, such as earthquake, blasts and mining or seismic tests on research models. Unique experiment design and shake table testing was performed to investigate seismic performance of a 3D RC building model with infill walls and advanced protection with polyurethane-based joints and fiber polymer reinforced light and emergency jackets. For the purpose of wider experimental activities, three methods for determination of the dynamic characteristics were used during multiple successive shake table tests following a dynamic pushover approach, and they are presented in detail. They are: inertance function through impact hammer tests, standard Fourier transformation of measured acceleration time history and digital image correlation. The expected differences in the results are related to the type and intensity of excitation used, the involvement of materials with different mechanical and physical properties, and with the different rate and extent of damage accumulation, as well as to local or global measurements. Y et, all methods lead to reliable results when a consistent methodology is being used, that takes into account locality or globality of measurements, leaving a choice for the most suitable one, depending on the site conditions. The inertance function method presented manifested its high efficiency in analysis of dynamic properties of large-scale structures and in monitoring of their changes caused by the damage and repair process. It offers quite a wide range of useful information, does not require very expensive equipment and its transportation cost is negligible. This method seems to be a proper diagnostic tool for simple experimental modal analysis of real structures and their structural elements, where detection of changes in the structural condition and in dynamic properties is required, also as a non-destructive testing and monitoring method. Digital image correlation proved to be a promising non-contact tool, strongly supporting the conventional instrumentation of shake table testing, while the Fourier transformation was used as a benchmark method yielding the most reliable results.
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Autorzy i Afiliacje

Arkadiusz Kwiecień
1
ORCID: ORCID
Zoran Rakicevic
2
Jarosław Chełmecki
1
Aleksandra Bogdanovic
2
Marcin Tekieli
1
Łukasz Hojdys
1
Matija Gams
3
Piotr Krajewski
1
ORCID: ORCID
Filip Manojlovski
2
Antonio Soklarovski
2
Omer Faruk Halici
4
Theodoros Rousakis
Vachan Vanian
5

  1. Faculty of Civil Engineering, Cracow University of Technology, Cracow, Poland
  2. IZIIS, Ss. Cyril and Methodius University, Skopje, North Macedonia
  3. Faculty of Civil and Geodetic Engineering, University of Ljubljana, Ljubljana, Slovenia
  4. Istanbul Technical University, Istanbul, Turkey
  5. Democritus University of Thrace, Xanthi, Greece

Abstrakt

A one-dimensional (1D) analytic example for dynamic displacement tracking in linear viscoelastic solids is presented. Displacement tracking is achieved by actuation stresses that are produced by eigenstrains. Our 1D example deals with a viscoelastic half-space under the action of a suddenly applied tensile surface traction. The surface traction induces a uni-axial shock wave that travels into the half-space. Our tracking goal is to add to the applied surface traction a transient spatial distribution of actuation stresses such that the total displacement of the viscoelastic half-space coincides with the shock wave produced by the surface traction in a purely elastic half-space. We particularly consider a half-space made of a viscoelastic Maxwell-type material. Analytic solutions to this tracking problem are derived by means of the symbolic computer code MAPLE. The 1D solution presented below exemplifies a formal 3D solution derived earlier by the present authors for linear viscoelastic solids that are described by Boltzmann hereditary laws. In the latter formal solution, no reference was made to shock waves. Our present solution demonstrates its validity also in the presence of singular wave fronts. Moreover, in our example, we show that, as was also indicated in our earlier work, the actuation stress can be split into two parts, one of them producing no stresses, and the other no displacements in two properly enlarged problems.
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Autorzy i Afiliacje

Hans Irschik
1
Michael Krommer
1
ORCID: ORCID

  1. Institute of Technical Mechanics, Johannes Kepler University of Linz, Austria

Abstrakt

The paper presents its contribution to tracking control design of mechanical systems in underactuated mode conditions, i.e. when the number of actuators is less than the number of possible control inputs. Fully actuated mechanical systems are quite well-researched and controller designs are well-developed for them as well. However, due to costs, weight, design, and performance regimes or due to an actuator failure, the underactuated control mode is required in applications. With the aid of the computational procedure for constrained dynamics (CoPCoD), the constrained dynamics, i.e. the reference motion dynamics, and tracking control in an underactuated mode are designed for an example of a three-link planar manipulator model with rigid and flexible links. A dynamic optimization problem is formulated in the paper to obtain optimal time courses of manipulator joint coordinates in underactuated mode conditions in order to apply them to a manipulator driving links controller.
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Autorzy i Afiliacje

Elżbieta Jarzębowska
1
ORCID: ORCID
Krzysztof Augustynek
2
Andrzej Urbaś
2

  1. Warsaw University of Technology, Nowowiejska 24, 00-665 Warsaw, Poland
  2. University of Bielsko-Biala, Willowa 2, 43-309 Bielsko-Biala, Poland

Abstrakt

The research presented in this paper concerns the influence of the rate of plastic deformation generated directly in the processes of severe plastic deformations on the microstructure and properties of three metals: copper, iron and zinc. The equal channel angular pressing (ECAP) method was used, and it was performed at a low plastic deformation rate of ∼ 0.04 s−1. The high plastic strain rate was obtained using the hydrostatic extrusion (HE) method with the deformation rate at the level of ∼ 170 s−1. For all three tested materials different characteristic effects were demonstrated at the applied deformation rates. The smallest differences in the mechanical properties were observed in copper, despite the dynamic recrystallization processes that occurred in the HE process. In Armco iron samples, dynamic recovery processes in the range of high plastic deformation rates resulted in lower mechanical properties. The most significant effects were obtained for pure zinc, where, regardless of the method used, the microstructure was clearly transformed into bimodal after the ECAP process, and homogenized and refined after the HE process. After the HE process, the material was transformed from a brittle state to a plastic state and the highest mechanical properties were obtained.
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Autorzy i Afiliacje

Mariusz Kulczyk
1
ORCID: ORCID
Monika Skorupska
1
Jacek Skiba
1
Sylwia Przybysz
1
Julita Smalc-Koziorowska
1

  1. Institute of High Pressure Physics of the Polish Academy of Sciences UNIPRESS, Sokołowska 29/37, 01-142 Warsaw, Poland

Abstrakt

In order to investigate the effect of the milling time on the corrosion resistance of the Mg65Zn30Ca4Pr1 alloy, powders of the alloy were prepared and milled for 13, 20, and 70 hours, respectively. The samples were sintered using spark plasma sintering (SPS) technology at 350◦C and pressure of 50 MPa. The samples were subjected to potentiodynamic immersion tests in Ringer’s solution at 37◦C. The obtained values of Ecorr were –1.36, –1.35, and –1.39 V, with polarization resistance Rp = 144, 189, and 101 Ω for samples milled for 13, 20 and 70 h, respectively. The samples morphology showed cracks and pits, thus signaling pitting corrosion.
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Autorzy i Afiliacje

Bartłomiej Hrapkowicz
1
ORCID: ORCID
Sabina Lesz
1
ORCID: ORCID
Aleksandra Drygała
1
ORCID: ORCID
Małgorzata Karolus
2
ORCID: ORCID
Klaudiusz Gołombek
3
ORCID: ORCID
Rafał Babilas
1
ORCID: ORCID
Julia Popis
1
ORCID: ORCID
Adrian Gabryś
1
ORCID: ORCID
Katarzyna Młynarek-Żak
1
ORCID: ORCID
Dariusz Garbiec
4

  1. Department of Engineering Materials and Biomaterials, Silesian University of Technology, ul. Konarskiego 18A, 44-100 Gliwice, Poland
  2. Institute of Materials Engineering, University of Silesia, ul. Pułku Piechoty 75 1a, 41-500 Chorzow, Poland
  3. Materials Research Laboratory, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland
  4. Łukasiewicz Research Network – Poznan Institute of Technology, ul. Ewarysta Estkowskiego 6, 61-755 Poznan, Poland

Abstrakt

The study investigated the effect of the fill factor, lattice constant, and the shape and type of meta-atom material on the reduction of mechanical wave transmission in quasi-two-dimensional phononic structures. A finite difference algorithm in the time domain was used for the analysis, and the obtained time series were converted into the frequency domain using the discrete Fourier transform. The use of materials with large differences in acoustic impedance allowed to determine the influence of the meta-atom material on the propagation of the mechanical wave.
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Autorzy i Afiliacje

Sebastian Garus
1
ORCID: ORCID
Wojciech Sochacki
1
ORCID: ORCID
Paweł Kwiatoń
1
ORCID: ORCID
Marcin Nabiałek
2
ORCID: ORCID
Jana Petrů
3
ORCID: ORCID
Mariusz Kubanek
4
ORCID: ORCID

  1. Faculty of Mechanical Engineering and Computer Science, Department of Mechanics and Fundamentals of Machinery Design, Czestochowa University of Technology, Dąbrowskiego 73, 42-201 Częstochowa, Poland
  2. Faculty of Production Engineering and Materials Technology, Department of Physics, Czestochowa University of Technology, Armii Krajowej 19, 42-201 Częstochowa, Poland
  3. Department of Machining, Assembly and Engineering Metrology, Faculty of Mechanical Engineering, VSB-Technical University of Ostrava,70833 Ostrava, Czech Republic
  4. Faculty of Mechanical Engineering and Computer Science, Department of Computer Science, Czestochowa University of Technology, Dąbrowskiego 73, 42-201 Częstochowa, Poland

Abstrakt

Along with changes in customer expectations, the process of ordering a house, especially one built with the most modern technology from prefabricated HQ 40-foot shipping containers, should take place in an atmosphere of free-flowing, customer-friendly conversation. Therefore, it is important that the company producing such a solution has a tool supporting such offers and orders when producing personalized solutions. This article provides an original approach to the automatic processing of orders based on an example of orders for residential shipping containers, natural language processing and so-called premises developed. Our solution overcomes the usage of records of the conversations between the customer and the retailer, in order to precisely predict the variant required for the house ordered, also when providing optimal house recommendations and when supporting manufacturers throughout product design and production. The newly proposed approach examines such recorded conversations in the sale of residential shipping containers and the rationale developed, and then offers the automatic placement of an order. Moreover, the practical significance of the solution, thus proposed, was emphasized thanks to verification by a real residential ship container manufacturing company in Poland.
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Autorzy i Afiliacje

Adam Dudek
1
ORCID: ORCID
Justyna Patalas-Maliszewska
2
ORCID: ORCID
Jacek Frączak
3

  1. University of Applied Sciences in Nysa, Armii Krajowej 7, 48-300 Nysa, Poland
  2. University of Zielona Góra, ul. Licealna 9,65-417 Zielona Góra, Poland
  3. Sanpol Sp. z o.o, Sulechowska 27a, 65-119, Zielona Góra, Poland

Abstrakt

The dynamic development of science requires constant improvement of approaches to modeling physical processes and phenomena. Practically all scientific problems can be described by systems of differential equations. Many scientific problems are described by systems of differential equations of a special class, which belong to the group of so-called singularly perturbed differential equations. Mathematical models of processes described by such differential equations contain a small parameter near the highest derivatives, and it was the presence of this small factor that led to the creation of a large mathematical theory. The work proposes a developed algorithm for constructing uniform asymptotics of solutions to systems of singularly perturbed differential equations.
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Autorzy i Afiliacje

Valentyn Sobchuk
1
ORCID: ORCID
Iryna Zelenska
1
ORCID: ORCID
Oleksandr Laptiev
1
ORCID: ORCID

  1. Taras Shevchenko National University of Kyiv, Ukraine

Abstrakt

In this paper, we propose a novel priority-aware solution named bypass to handle high- and low-priority traffic in multi-layer networks. Our approach assumes diversification of elastic optical spectrum to ensure additional resources reserved for emergency situations. When congestion occurs, the solution dynamically provides new paths, allocating a hidden spectrum to offload traffic from the congested links in the IP layer. Resources for a bypass are selected based on traffic priority. High-priority traffic always gets the shortest bypasses in terms of physical distance, which minimizes delay. Bypasses for low-priority traffic can be established if the utilization of the spectrum along the path is below the assumed threshold. The software-defined networking controller ensures the global view of the network and cooperation between IP and elastic optical layers. Simulation results show that the solution successfully reduces the amount of rejected high-priority traffic when compared to regular bypasses and when no bypasses are used. Also, overall bandwidth blocking probability is lower when our priority-aware bypasses are used.
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Autorzy i Afiliacje

Edyta Biernacka
1
ORCID: ORCID
Piotr Boryło
1
ORCID: ORCID
Piotr Jurkiewicz
1
ORCID: ORCID
Robert Wójcik
1
ORCID: ORCID
Jerzy Domżał
1
ORCID: ORCID

  1. Institute of Telecommunications, AGH University of Science and Technology, Kraków, Poland

Abstrakt

Although laser scanning ideas and hardware solutions are well-known to experts in the field, there is still a large area for optimization. Especially, if long-range and high-resolution scanning is considered, the smallest defects in optical quality should be perfected. On the other hand, the simplicity, reliability, and finally the cost of the solution plays an important role, too. In this paper, a very simple but efficient method of optical correction is presented. It is dedicated to laser scanners operating from inside cylindrical glass domes. Such covers normally introduce aberrations into both the laser beam and receiving optics. If these effects are uncorrected, the laser scanner performance is degraded both in terms of angular resolution and maximum range of operation. It may not be critical for short-range scanning applications; however, if more challenging concepts are considered, this issue becomes crucial. The proposed method does not require sophisticated optical solutions based on aspheric or freeform components, which are frequently used for similar purposes in imaging-through-dome correction but is based on a simple cylindrical refractive correction plate.
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Autorzy i Afiliacje

Jacek Wojtanowski
1
ORCID: ORCID

  1. Institute of Optoelectronics, Military University of Technology, ul. gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland

Abstrakt

Today’s electricity management mainly focuses on smart grid implementation for better power utilization. Supply-demand balancing, and high operating costs are still considered the most challenging factors in the smart grid. To overcome this drawback, a Markov fuzzy real-time demand-side manager (MARKOV FRDSM) is proposed to reduce the operating cost of the smart grid system and maintain a supply-demand balance in an uncertain environment. In addition, a non-linear model predictive controller (NMPC) is designed to give a global solution to the non-linear optimization problem with real-time requirements based on the uncertainties over the forecasted load demands and current load status. The proposed MARKOV FRDSM provides a faster scale power allocation concerning fuzzy optimization and deals with uncertainties and imprecision. The implemented results show the proposed MARKOV FRDSM model reduces the cost of operation of the microgrid by 1.95%, 1.16%, and 1.09% than the existing method such as differential evolution and real coded genetic algorithm and maintains the supply-demand balance in the microgrid.
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Autorzy i Afiliacje

G. K. Jabash Samuel
1
ORCID: ORCID
M. S. Sivagama Sundari
2
R. Bhavani
3
A. Jasmine Gnanamalar
4

  1. Department of Electrical and Electronics Engineering, Rohini College of Engineering and Technology, Kanyakumari, India
  2. Department of Electrical and Electronics Engineering, Amrita College of Engineering and Technology, Nagercoil, India
  3. Department of Electrical and Electronics Engineering, Mepco Schlenk Engineering College, Sivakasi-626004, India
  4. Department of Electrical and Electronics Engineering, PSN College of Engineering and Technology, Anna University, India

Abstrakt

Proper design of power installations with the participation of power cables buried in homogeneous and thermally well-conductive ground does not constitute a major problem. The situation changes when the ground is non-homogeneous and thermally low-conductive. In such a situation, a thermal backfill near the cables is commonly used. The optimization of thermal backfill parameters to achieve the highest possible current-carrying capacity is insufficiently described in the standards. Therefore, numerical calculations based on computational fluid dynamics could prove helpful for designers of power cable lines. This paper studies the influence of dimensions and thermal resistivity of the thermal backfill and thermal resistivity of the native soil on the current-carrying capacity of power cables buried in the ground. Numerical calculations were performed with ANSYS Fluent. As a result of the research, proposals were made on how to determine the current-carrying capacity depending on the dimensions and thermal properties of the backfill. A proprietary mathematical function is presented which makes it possible to calculate the cable current-carrying capacity correction factor when the backfill is used. The research is expected to fill the gap in the current state of knowledge included in the provisions of standards.
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Autorzy i Afiliacje

Seweryn Szultka
1
ORCID: ORCID
Stanisław Czapp
1
ORCID: ORCID
Adam Tomaszewski
2
ORCID: ORCID

  1. Faculty of Electrical and Control Engineering, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland
  2. Institute of Fluid-Flow Machinery, Polish Academy of Sciences, Fiszera 14, 80-231 Gdansk, Poland

Abstrakt

The issue of transportation is a particular type of mathematical programming that facilitates searching for and determining an optimal distribution network, considering the set of suppliers and recipients. This paper uses a numerical example to present a solution to a transport problem utilizing classical computation methods, i.e., the northwest corner, the least cost in a matrix, and the VAM approximation method. The objective of the paper was to develop tools in the form of algorithms that would then be implemented in three various computing environments (R, GNU Octave, and Matlab) that allow us to optimize transport costs within an assumed supply network. The model involved determining decision variables and indicating limiting conditions. Furthermore, the authors interpreted and visualized the obtained results. The implementation of the proposed solution enables users to determine an optimal transport plan for individually defined criteria.
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Autorzy i Afiliacje

Joanna Szkutnik-Rogoż
1
ORCID: ORCID
Jerzy Małachowski
2
ORCID: ORCID

  1. Military University of Technology, Cybernetics Faculty, gen. Kaliskiego 2, 00-908 Warsaw, Poland
  2. Military University of Technology, Faculty of Mechanical Engineering, gen. Kaliskiego 2, 00-908 Warsaw, Poland

Abstrakt

In this paper three algorithms of motion planning for two-input, one-chained nonholonomic systems are presented. The classical Murray-Sastry algorithm is compared with two original algorithms aimed at optimizing energy of controls. Based on the generalized Campbell- Baker-Hausdorff-Dynkin formula applied to the systems, some observations are made concerning the optimal relationship between amplitudes and phases of harmonic controls. The observations help to optimize a selection of controls and to design new algorithms for planning a sub- optimal trajectory between given boundary configurations. It was also shown that for those particular systems the generalized C-B-H-D formula is valid not only locally (as in a typical case) but also globally. Simulations performed on the five-dimensional chain system facilitate distinguishing the proposed algorithms from the Murray-Sastry algorithm and to illustrate their features. Systems in a chained form are important from a practical point of view as they are canonical for a class of systems transformable into this form. The most prominent among them are mobile robots with or without trailers.
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Autorzy i Afiliacje

Ignacy Duleba
1
ORCID: ORCID
Iwona Karcz-Duleba
2
ORCID: ORCID

  1. Department of Cybernetics and Robotics
  2. Department of Control Systems and Mechatronics Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland

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