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1

Metody obliczania studni opuszczanych

Szymczak-Graczyk Anna

Przegląd Budowlany

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2024

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R. 95, nr 4

91--94

PL

W pracy przedstawiono metody obliczania studni opuszczanych, uwzględniając metody tradycyjne oraz współczesne numeryczne metody obliczeniowe. Omówione zostały najważniejsze zagadnienia, na które należy zwrócić uwagę przy projektowaniu studni, takie jak: zapewnienie studni pogrążalności, w przypadku posadowienia w gruntach nawodnionych, zagwarantowanie studni stateczności na wypór, zaprojektowanie pod względem wytrzymałościowym płaszcza studni, noża studni, korka betonowego studni oraz płyty dennej, jak również uwzględnienie technologii wykonywania studni.

EN

The paper presents methods of calculating sunk wells, taking into account traditional methods and modern numerical calculation methods. The most important issues to be paid attention to when designing a well are discussed, such as proper sinkability of the well, buoyancy stability of the well when it is implemented in wet soils, design with reference to the strength of the steining, design of the cutting edge, bottom plug and a bottom plate as well as taking into account well completion technology.

2

Mechanika istniejących ścian murowanych w kierunku prostopadłym do płaszczyzny ściany - metody analizy

Szyszka Marcin

Przegląd Budowlany

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2024

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R. 95, nr 4

132--135

PL

Rzetelne szacowanie nośności murów historycznych, w szczególności w strefach sejsmicznych, jest niezbędne i kluczowe z wielu powodów. W artykule omówiono stosowane obecnie metody obliczeniowe w powyższym kontekście. Są to odpowiednio metody: siłowe, przemieszczeniowe, „kołysania”, numeryczne. Przedstawiono założenia każdej z metod i ich podstawy teoretyczne. Przedyskutowano również ich zalety i wady oraz przydatność w ujęciu inżynierskim i naukowym. Poruszono takie aspekty jak stopień złożoności, wymagane dane wejściowe oraz adekwatność danej metody do stopnia znajomości konstrukcji.

EN

Reliable assessment of historical masonry walls, particularly in seismic zones is indispensable and critical for many reasons. In article are discussed methods in current use for the above-mentioned issue. These are methods: force-based, displacement-based, „rocking”, numerical. Described are assumptions and theoretical background of these methods. Advantages and disadvantages of the methods are listed along with their possible potential both in scientific and engineering field. Discussed are aspects such as level of complexity, required input data and adequacy of given method to possessed knowledge of structure.

3

Algebraic active disturbance rejection to control a generalized uncertain second-order flat system

Aguilar-Ibanez Carlos, Suarez-Castanon Miguel S., Saldivar Belem, Jimenez-Lizarraga Manuel A., de Jesus Rubio Jose, Mendoza-Mendoza Julio

International Journal of Applied Mathematics and Computer Science

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2024

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Vol. 34, no. 2

185--198

EN

We introduce an algebraically active disturbance rejection-based control solution for the trajectory tracking problem of an uncertain second-order flat system with unknown external disturbances. To this end, we first algebraically identify the system’s unknown dynamics and the external disturbances with a linear set of time-varying integral expressions for the output and the control signal. We use the identified dynamics on an online feedback cancellation scheme to linearize the second-order system and cancel the uncertainties. With a proportional-integral controller we stabilize the linearized system without the need to estimate the velocity and have feedback from it. We carry out the stability analysis using linear systems theory. Finally, we evaluate the effectiveness of the proposed controller in a partially known 2-DOF manipulator.

4

Innowacyjne fundamenty wąskotrzonowych słupów linii elektroenergetycznych

Labocha Sławomir, Paluszyński Jarosław

Materiały Budowlane

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2023

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nr 7

6--10

PL

W artykule przedstawiono innowacyjne rozwiązania fundamentów przeznaczonych pod wąskotrzonowe stalowe kratowe słupy napowietrznych linii elektroenergetycznych wysokiego napięcia. Opisano przykładowe rozwiązania konstrukcyjne nowych fundamentów dostosowane do wymagań aktualnych norm PN-EN 50341-1:2013 i PN-EN 50341-2-22:2022-06 i porównano je z dotychczas stosowanymi w praktyce fundamentami do posadowienia słupów wąskotrzonowych. Rozważania zilustrowano przykładem numerycznym, w którym, posiłkując się metodą elementów skończonych, dokonano weryfikacji nośności w gruncie fundamentów tradycyjnego oraz zoptymalizowanego. Porównanie rezultatów prowadzi do konkluzji o dużej technicznej przydatności i znacznym stopniu oszczędności rozwiązań nowych konstrukcji fundamentów.

EN

In the article one presented innovative solutions of foundations of narrow steel lattice towers for overheading high voltage transmission. One described example of structural solutions of new foundations adapted to requirements of current standards PN-EN 50341-1:2013 and PN-EN 50341-2-22:2022-06 and one compared it with known applied foundations in practice for the foundation of narrow towers. Considerations were illustrated with the numerical example using finite element method and made the verification of the capacity in the ground of foundations of traditional and optimized solution. The comparison of results leads to the conclusion about the large technical usefulness and the considerable degree of saving of solution of new structural constructions of foundations.

5

A Numerical Study to Determine the Effect of an Insulator Location on the Transient Heat Transfer

Mageed Ridha Hameed, Kurji Hayder J., Abdulrasool Ali A.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

105--114

EN

Given the importance of thermal insulation in the walls of buildings to provide both electrical energy and thermal comfort in different weathers. In this research, the ANSYS-14 simulation program was used, considered one of the programs used to evaluate the thermal behavior of buildings, considering the effect of weather changes and building components during the steady and unsteady heat transfer of a composite wall from several layers. The simulation program was used for four types of insulation inside the wall with different thermal properties (Glass-Fiber Slab, Polyurethane Board, Hardboard (Medium) and Softwoods). A model was built for a traditional wall without an insulator and a model for a traditional wall that contains an insulator in different locations (from the outside, in the middle, and from the inside). Also, the model was isolated from the top and bottom surfaces, and each insulation material was applied in three locations in the wall. The conventional composite wall was exposed to a constant thermal load of 60 °C from the outside, and the inside wall was exposed to a thermal load of 25 °C This study focused on three steps. The first step is to know the best type of the four thermal insulators used in this study. The second step was to evaluate the best location of the insulator in the wall. The third step included the results of the previous two steps through which the best insulator was chosen and the best location in the wall. Three values of insulator thickness 2, 5 and 8 cm were used. Through the results of the study, it was found that placing the insulator on the outside of the wall plays a large role in reducing the rate of unsteady heat transfer and that its effect decreases by approaching the steady state, as it does not affect it in the case of the total steady state. The results also showed that the rate of unsteady heat transfer decreases by decreasing the thermal diffusivity of materials. It is also noticeable that the effect of the density and specific heat capacity appears clearly at the beginning of the thermal loading on the material. That effect decreases by approaching the steady state as the effect of the heat transfer coefficient of conduction appears. It was also found that both hardboard and polyurethane are the best in thermal insulation. It was also observed that the relationship between heat transfer rate and thickness is inverse-linear.

6

Effect of boundary conditions and metal alloy layer on natural frequencies of fibre metal laminates

Rao Nandure Narayan, Sirisha Sirapu, Rao Pavuluri M.V., Bobba Sujith

Composites Theory and Practice

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2023

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R. 23, nr 2

97--103

EN

The natural frequencies and mode shapes of fibre metal laminates (FMLs) were numerically investigated and validated using commercially available finite element analysis software (ANSYS). Various grades of GLARE and FML were considered for free vibration analysis, and the effect of the central metal layer and aspect ratios on the frequencies were analysed for simply supported, clamped edge conditions. The obtained fundamental frequencies, natural frequencies and mode shapes comply with the available literature. The effect of the outermost metal layer on the natural frequencies was also investigated for various combinations of edge conditions. The obtained results indicate that there is a significant effect of the central and outermost metal layer on the natural frequencies, irrespective of the edge conditions and aspect (width/length) ratios.

7

A numerical approach in applying panel method for the added mass of a group of sections in fluids

Zhang D., Li P., Wang Q., Yang Y.

Archives of Mechanics

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2023

|

Vol. 75, nr 1-2

151--168

EN

This paper firstly expands an efficient numerical methodology developed from the source panel method to the added mass calculation of long column systems in fluid. Structures submerged in fluid are considered as two-dimensional and are discretized into a number of source panels. The influence coefficient matrices and the potential function are then calculated and the fluid forces are calculated by the unsteady Bernoulli equation. Finally, we utilize this present method to calculate the mass coefficients of some typical problems, which effectively verifies its feasibility and accuracy. This method takes into account both applicability and computational efficiency. On the one hand, in contrast to the analytical method which is only applicable to specific cross-sections, this method is applicable to arbitrary boundaries with C0 continuity in mathematics. On the other hand, this method requires less mesh and computation than commercial software. This paper extends the application of the source panel method which is widely used in aerodynamics to provide a reference for added mass calculation problems in engineering.

8

Assessment of energy consumption by a numerical method technique to decide on installing solar power plants in Thailand

Trerutpicharn Songkrit, Kongsong Waranon, Kongbenjapuch Kijbodi

Przegląd Elektrotechniczny

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2021

|

R. 97, nr 6

144--153

EN

A solar power system was designed for sustained loads; however, there was a problem when using the system for a long period of time, so it could not function as designed. This research found methods or tools to solve the problem or reduce the above problems to an acceptable level to make long-term use for loads that would continuously function. As a result, there was higher performance and reliability from the study of the tools and methods for solving the problem. It was found that numerical methods could be used to solve these problems and were responsive to the engineering applications. This paper was research on developing a model and presenting the analytical content in another form according to the research report, so to be developed in terms of energy considerations and system design to make the use of the system most efficient and beneficial. This was due to the use of solar power systems with an improper design as backup power systems. Hence, there are often problems in terms of economics and system performance involved. In addition, the size of the system must be too large in order to provide a sufficient energy supply to the energy storage system.

PL

Zaprojektowano system zasilania energią słoneczną do ciągłych obciążeń; jednak wystąpił problem podczas używania systemu przez długi czas, więc nie mógł on działać zgodnie z przeznaczeniem. W ramach tych badań znaleziono metody lub narzędzia do rozwiązania problemu lub zredukowania powyższych problemów do akceptowalnego poziomu w celu długotrwałego wykorzystania obciążeń, które będą stale funkcjonować. W rezultacie uzyskano wyższą wydajność i niezawodność. Stwierdzono, że do rozwiązania tych problemów można zastosować metody numeryczne i są one przydatne w zastosowaniach inżynierskich.

9

Preliminary support design for underground mine adit, Artana mine, Kosovo

Zeqiri Kemajl, Ibishi Gzim, Shabani Musa, Kortnik Joze, Bilir Mehmet Erdinç, Geniş Melih, Yavuz Mahmut, Hetemi Muhamedin, Bacak Gürkan

Mining Science

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2021

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Vol. 28

141--159

EN

In this paper, preliminary support design of the main underground opening (i.e., mine adit) located at the Artana lead-zinc mine, Kosovo, was examined by employing both conventional and numerical methods for safe underground excavation and design. In order to conduct field studies including discontinuity surveying and sampling for laboratory testing two empirical methods, namely rock mass rating (RMR) and geological strength index (GSI) were employed. For the purpose of determining necessary support units RMR system was utilized. However, these kind of systems can take into account for neither the depth of underground opening nor in situ field stresses. For this reason, empirical design methods (i.e., RMR system) failed to investigate the performance of rock support units; therefore, a 2D finite element analysis program was used to assess the performance of the proposed support systems. This indicated that RMR system might not be applicable for poor and very poor rock masses located in deep environment (i.e., 300 and 400 m). Moreover, this is linked to the fact that the RMR system does not consider in situ stress conditions. This study showed that when empirical methods are supported by numerical analysis, the preliminary support system design will be much more reliable.

10

Methodology for underground mining method selection

Mijalkovski Stojance, Peltechki Dragi, Despodov Zoran, Mirakovski Dejan, Adjiski Vancho, Doneva Nikolinka

Mining Science

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2021

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Vol. 28

201--216

EN

The mining method selection for underground mining is one of the most important decisions when designing a mine. This selection depends on the mining-geological, mining-technical and economic factors. The mining method selection for underground mining can be described as a multi-criteria decision-making process, as several factors are involved in the selection process. In this paper, a methodology for rational and optimal mining method selection for underground mining of metallic mineral resources has been developed. First, a rational selection of the four best-ranked mining methods for underground mining is performed using numerical methods (Nicholas' approach and the modified approach of Nicholas, i.e., UBC selection of mining method). This is followed by the optimal selection of underground mining method using multi-criteria decision-making methods (ELECTRE, PROMETHEE, AHP, and integrated AHP-PROMETHEE) and by comparing the obtained rankings, the optimal mining method is selected.

11

A Numerical Method for the Design of the U-Shaped Segmental Tunnel Lining under the Impact of Earthquakes: A Case Study of a Tunnel in the Hanoi Metro System

Nguyen Chi Thanh, Do Ngoc Anh, Pham Van Vi, Gospodarikov Alexandr

Inżynieria Mineralna

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2021

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no. 2

305--320

EN

Circular tunnels are usually encountered when excavation tunnel. However, the U-shaped tunnel lining is used a lot in practice because of it’s advantages. However, there are not many studies in the world to calculate and design for underground structures with U-shaped tunnel lining, especially in the case of tunnels being affected by earthquakes. This paper proposes a new numerical-HRM method approach for the analysis of U-shaped segmental tunnel lining under the impact of earthquakes. Hanoi is the capital of Vietnam, this is a big city with more than 8 million people. Hanoi is located between two major fault systems, the Red River fault system and the Son La-Dien Bien-Lai Chau fault system. Therefore, the Hanoi area is assessed as likely to be affected by earthquakes of magnitude Mw = 6.1 up to 6.5 Richter. The Hanoi metro system is constructed by TBM and the U-shaped segmental tunnel lining is also one of the types of tunnel lining considered for use in the construction of metro tunnels in Hanoi. The improved HRM method has been used to investigate the effect of joints in the tunnel lining from the Hanoi system metro under the impact of earthquakes is conducted considering from the results of the tunnel lining behavior in terms of bending moment (M), normal forces (N) and tunnel lining displacements (δn) in both cases: the U-shaped continuous tunnel lining and the U-shaped segmental tunnel lining.

12

Aaliza ryzyka zarysowania termicznego masywnych płyt fundamentowych - propozycja metodyki postępowania i wytyczne budowy modeli MES

Smolana Aneta, Klemczak Barbara

Inżynieria i Budownictwo

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2021

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R. 77, nr 9-10

471--476

PL

Przedstawiono doświadczenia związane z analizą masywnych płyt fundamentowych, które mogą być pomocne podczas projektowania tego rodzaju konstrukcji oraz przewidywania ryzyka zarysowania. Przedstawiono 3 etapy analizy konstrukcji masywnej: ocenę masywności konstrukcji, analizę uproszczoną z wykorzystaniem metod analitycznych oraz analizę numeryczną. Szerzej omówiono wytyczne budowy modelu MES oraz jego możliwe uproszczenia nie wpływające na wyniki obliczeń.

EN

The article presents experiences related to the analysis of massive foundation slabs, which can be helpful in the design of this type of structure, as well as in predicting the cracking risk. Three stages of the analysis of a massive structure were presented: assessment of the massivity index of the structure, simplified analysis with the use of analytical methods, and numerical analysis. The recommendations for the FE model and its possible simplifications not affecting the calculation results are discussed in more detail.

13

Investigation of E-Cigarette Smoking Model with Mittag-Leffler Kernel

Uçar Esmehan, Uçar Sümeyra, Evirgen Fırat, Özdemir Necati

Foundations of Computing and Decision Sciences

|

2021

|

Vol. 46, No. 1

97--109

EN

Smoking is the most lethal social poisoning event. The World Health Organization defines smoking as the most important preventable cause of disease. Around 4.9 million people worldwide die from smoking every year. In order to analysis this matter, we aim to investigate an e-cigarette smoking model with Atangana-Baleanu fractional derivative. We obtain the existence conditions of the solution for this fractional model utilizing fixed-point theory. After giving existence conditions, the uniqueness of the solution is proved. Finally, to show the effect of the Atangana-Baleanu fractional derivative on the model, we give some numerical results supported by illustrative graphics.

14

The implicit numerical method for the one-dimensional anomalous subdiffusion equation with a nonlinear source term

Błasik Marek

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

|

Vol. 69, nr 6

art. no. e138240

EN

In the paper, the numerical method of solving the one-dimensional subdiffusion equation with the source term is presented. In the approach used, the key role is played by transforming of the partial differential equation into an equivalent integro-differential equation. As a result of the discretization of the integro-differential equation obtained an implicit numerical scheme which is the generalized Crank-Nicolson method. The implicit numerical schemes based on the finite difference method, such as the Carnk-Nicolson method or the Laasonen method, as a rule are unconditionally stable, which is their undoubted advantage. The discretization of the integro-differential equation is performed in two stages. First, the left-sided Riemann-Liouville integrals are approximated in such a way that the integrands are linear functions between successive grid nodes with respect to the time variable. This allows us to find the discrete values of the integral kernel of the left-sided Riemann-Liouville integral and assign them to the appropriate nodes. In the second step, second order derivative with respect to the spatial variable is approximated by the difference quotient. The obtained numerical scheme is verified on three examples for which closed analytical solutions are known.

15

Rozwój metod obliczeniowych w budowie maszyn i pojazdów

Rusiński Eugeniusz, Smolnicki Tadeusz

Przegląd Mechaniczny

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2020

|

nr 10

31--38

PL

Obecnie trudno sobie wyobrazić inżyniera mechanika bez znajomości metod numerycznych (CAE). Powszechne korzystanie z komputerów i rozwój metod numerycznych przyczyniły się do zwiększenia jakości projektów inżynierskich. W artykule przedstawiono rozwój metod numerycznych i ich praktyczne zastosowania w budowie maszyn i pojazdów. Precyzja obliczeń oraz możliwość realizacji w rzeczywistości wirtualnej złożonych symulacji zwiększyła niezawodność produkowanych maszyn i pojazdów z jednoczesnym obniżeniem kosztów.

EN

Nowadays, is difficult to image mechanical engineer without skills of computer aided engineering (CAE) methods. Common use of computers, PC popularity and numerical methods development have been the reason of rapid growth of engineering design quality. Development of numerical methods and their practical applications in machine and vehicle building were presented. Precision of calculations as well as possibility of realization in virtual reality complex simulations increased reliability of produced machines and vehicles with simultaneous cost decreasing.

16

Projekt konstrukcji przekrycia pływalni miejskiej

Sęk Anna Małgorzata, Prusiel Jolanta Anna

Przegląd Budowlany

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2020

|

R. 91, nr 5

43--48

PL

Opracowano koncepcję architektoniczną obiektu pływalni miejskiej z dwoma wariantami konstrukcji przekrycia w postaci powłoki walcowej. Przeprowadzono analizę porównawczą sił wewnętrznych w powłoce uzyskanych metodą numeryczną i analityczną. Zwymiarowano żelbetową konstrukcję przekrycia powłokowego zgodnie z obowiązującymi eurokodami.

EN

The architectural and construction concept of the swimming pool with two types of cylindrical shell roof was designed. A comparative analysis of internal forces using a numerical and analytical method has been carried out. The reinforced structure of cylindrical shell roof has been designed according to required eurocodes.

17

Analiza systemów termoizolacyjnych nieingerujących w fasadę budynku

Ksit Barbara, Jankowiak Magdalena

Przegląd Budowlany

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2020

|

R. 91, nr 11

39--42

PL

W artykule przedstawiono doświadczalne systemy występujące na rynku budowlanym, przeznaczone do ocieplania budynków od wewnątrz. Zaprezentowano wytyczne prawne dotyczące termoizolacji, powołując się na Dyrektywę Parlamentu Europejskiego oraz normy polskie. Zestawiono podstawową wiedzę na temat syntetycznych materiałów komórkowych i przedstawiono odmiany stosowane przy ocieplaniu od wewnątrz. Sklasyfikowano systemy ze względu na dyfuzję otwartą oraz zamkniętą. Wybrane parametry techniczne systemów przedstawiono w postaci wykresów. Przedstawiono algorytm postępowania w przypadku modelowania przegrody uwzględniające parametry klimatyczne, zacinające deszcze, występujące w danej okolicy, zawilgocenie budynku oraz magazynowanie ciepła i wilgoci przez przegrodę.

EN

The article presents experimental systems available on the construction market, intended for internal insulation of buildings. It describes legal guidelines for thermal insulation with reference to the Directive of the European Parliament as well as to Polish standards. It compiles basic knowledge on synthetic cellular materials and presents the variants used for internal insulation. It also contains a classification of the systems according to open and closed diffusion. Selected technical parameters of the systems have been presented in the form of charts. An algorithm of conduct in the case of partition modeling has been presented, taking into account climatic parameters, slanting rains occurring in a given area, moisture content of the building and storage of heat and moisture by the partition.

18

Optimization of the regulated maintenance periodicity on military equipment products operated according to their technical condition

Mirnenko Volodymyr, Dyptan Valentyn, Pustovyi Serhii, Radko Oleg, Yablonskyi Petro

Journal of KONBiN

|

2020

|

Vol. 50, iss. 4

237--249

EN

The article is dedicated to the optimization problem of the regulated maintenance periodicity for military products operated according to their technical condition. The analytical method of optimization for the exponential law of the time distribution between failures and the numerical optimization method for the diffusion-monotonic law are taken into consideration. The search for the extreme value of the regulated maintenance periodicity for the diffusionmonotonic distribution law was conducted with the use of the numerical method applying Mathcad 15.0. The dependencies of both the technical utilization factor and its derivative on the regulated maintenance periodicity at certain values of the model parameters were obtained.

PL

W pracy podjęto problem optymalizacji okresowości obsługiwania planowego dla produktów wojskowych eksploatowanych według stanu technicznego. Rozważano analityczną metodę optymalizacji dla wykładniczego prawa rozkładu czasu między awariami oraz metodę numeryczną optymalizacji dla prawa dyfuzyjno-monotonicznego (za pomocą Mathcada 15.0). Uzyskano zależności zarówno współczynnika wykorzystania technicznego, jak i jego pochodnej od okresowości obsługiwania planowego przy określonych wartościach parametrów modelu.

19

Przewidywanie temperatury twardnienia i naprężeń termicznych w fundamencie śluzy

Żmij Aneta, Klemczak Barbara, Azenha Miguel, Schlicke Dirk

Cement Wapno Beton

|

2019

|

R. 22/84, nr 4

286--295

PL

W pracy przedstawiono symulację numeryczną i analityczną temperatury twardnienia, odkształceń i naprężeń termicznych w fundamencie śluzy Sülfeld-Süd w Niemczech, której budowa zakończyła się w listopadzie 2008 r. Przedstawione wyniki dotyczą jednego z etapów budowy tego fundamentu o rzeczywistych wymiarach 41,5 x 26,5 m i grubości 2 m. Analizę numeryczną przeprowadzono w programie DIANA MES. Uzyskane wyniki zostały porównane z rzeczywistymi pomiarami temperatury, odkształceń i naprężeń w fundamencie śluzy.

EN

The study presents the numerical and analytical simulation of the hardening temperature, thermal strains and stresses in the foundation of the sluice Sülfeld-Süd in Germany, which construction process was completed in November 2008. The present study relates to a particular construction stage of this foundation with real dimensions of 41.5 x 26.5 m and a thickness of 2 m. The numerical analysis was performed in the software DIANA FEA. The obtained results are compared with actual measurements of temperature, strains and stresses in the sluice foundation.

20

Mathematical model of asynchronous pump drive with distributed mechanical parameters

Łukasik Z., Czaban A., Szafraniec A.

Przegląd Elektrotechniczny

|

2018

|

R. 94, nr 6

155-159

EN

The paper presents a mathematical model of a complex electromechanical system. The electromechanical system features a deep-groove asynchronous motor, which drives a vertical pump. I this case the motor and pump are connected through a long shaft with distributed parameters. The motor is powered from a power transformer. The general model of the system was developed on the basis of interdisciplinary variational approaches. The final state equations are represented in the Cauchy normal form. This methodology gives the possibility of using both explicit and implicit numerical methods.

PL

W pracy przedstawiono model matematyczny złożonego układu elektromechanicznego, składającego się z głębokożłobkowego silnika asynchronicznego, który przez długi wał o parametrach rozłożonych napędza pompę pionową. Silnik zasilany jest z transformatora mocy. Ogólny model układu opracowano na podstawie interdyscyplinarnych podejść wariacyjnych. Końcowe równania stanu reprezentowane są w normalnej postaci Cauchy’ego, co daje możliwość wykorzystania zarówno jawnych, jak i ukrytych metod numerycznych.