Wyniki wyszukiwania - BazTech

1

Analiza naprężeń w słupie OWS-7 obudowy wykopu firmy Kopras w zależności od położenia rozpory oraz od rozkładu parcia gruntu działającego na obudowę

Buczkowski Wiesław, Kopras Marek, Fleming Wojciech

Przegląd Budowlany

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2025

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R. 96, nr 3

77--84

PL

Artykuł prezentuje kompleksową analizę naprężeń w słupach systemowej obudowy słupowej, stosowanych do zabezpieczania głębokich wykopów. W badaniu uwzględniono wpływ różnych schematów rozkładu parcia gruntu, takich jak równomierny, hydrostatyczny oraz modele zaproponowane przez Terzaghiego, Klennera, Lehmanna i Siemińską-Lewandowską. Dodatkowo przeanalizowano znaczenie wysokości położenia rozpory rolkowej względem słupa i jej wpływ na generowane naprężenia. Badania, przeprowadzone przy zastosowaniu metody różnic skończonych przy wykorzystaniu funkcjonału energii sprężystej pozwoliły na precyzyjną ocenę rozkładu momentów zginających w zależności od przyjętych założeń obciążeniowych. Wyniki wskazują, że schemat Terzaghiego generuje największe momenty zginające, przewyższając wartości wynikające z innych modeli, takich jak hydrostatyczny czy równomierny. Szczegółowa metodyka wraz z analizą wyników została zamieszczona w artykule. Artykuł podkreśla praktyczne znaczenie optymalnego doboru schematów obciążeń i konfiguracji konstrukcji w kontekście zwiększenia bezpieczeństwa oraz efektywności kosztowej obudów systemowych. Wyniki badania stanowią istotny krok w kierunku dalszej optymalizacji konstrukcji zabezpieczających wykopy i ich adaptacji do zmiennych warunków gruntowych.

EN

The article presents a comprehensive analysis of stresses in posts of a system shoring structure used for securing deep excavations. The study considers the impact of various soil pressure distribution schemes, such as uniform, hydrostatic, and models proposed by Terzaghi, Klenner, Lehmann, and Siemińska-Lewandowska. Additionally, the significance of the vertical position of the roller brace relative to the post and its effect on the generated stresses is analyzed. The research, conducted using the finite difference method and applying the elastic energy functional, enabled a precise evaluation of bending moment distribution based on the adopted load assumptions. The results indicate that Terzaghi’s scheme generates the highest bending moments, surpassing the values derived from other models, such as hydrostatic or uniform. Detailed methodology and analysis of the results are included in the article. The article emphasizes the practical importance of optimizing load distribution schemes and structural configurations to enhance safety and cost-efficiency in system shoring structures. The findings represent a significant step toward further optimization of excavation shoring designs and their adaptation to varying soil conditions.

2

Numerical analysis and experimental studies three-layer slabs of the Hoff

Sadowska-Buraczewska Barbara, Głodkowska Wiesława

Materiały Budowlane

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2025

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nr 7

1--9

EN

The paper concerns three-layer slabs of the Hoff in terms of their use as independent slab floor elements. Three variants of the panels were analyzed, differing in the material from which the cladding and the core of the board were made. The result of the analysis was to determine the relationship between the load of the three-layer slab and its vertical displacements (deflections). The practical possibility of using the variational finite difference approach (MRS) and the finite element method (FEM) for the calculation of plate three-layer elements of the Hoff and homogeneous, isotropic plates has been demonstrated. For three variants of the plate, computer simulations were carried out using these methods and experimental verification of one of the variants was carried out. The article presents only a fragment of extensive experimental and analytical research.

PL

W artykule zaprezentowano płyty trójwarstwowe Hoffa w aspekcie zastosowania ich jako samodzielnych płytowych elementów stropowych. Przeanalizowano trzy warianty płyt z różnymi okładzinami i rdzeniem. Wynikiem analiz było określenie zależności pomiędzy wielkością obciążenia płyty trójwarstwowej a jej przemieszczeniami pionowymi (ugięciami). Wykazano praktyczną możliwość stosowania metody wariacyjnego ujęcia różnic skończonych (MRS) i metody elementów skończonych (MES) do obliczania płytowych elementów trójwarstwowych Hoffa oraz izotropowych płyt jednorodnych. Przeprowadzono symulacje komputerowe tymi metodami trzech wariantów płyty oraz dokonano weryfikacji doświadczalnej jednego z wariantów. W artykule przedstawiono tylko fragment szerokich badań doświadczalnych i analitycznych.

3

Can artificial intelligence predict a tsunami?

Wójcik Daria, Niewiadomska Alicja, Paszyński Maciej

Computer Science

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2025

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T. 26 (4)

163--180

EN

In this article, we build a model for tsunami simulation based on physics-informed neural networks and the finite difference method. We then check howthe numerical results obtained using these two methods differ from each other.Assuming that the finite difference method gives accurate results, we estimatethe error resulting from the use of physics-informed neural networks. We compare this estimate with surveys conducted among computer science studentsin order to assess the level of public trust among specialists in the numericalresults obtained using artificial intelligence tools. In particular, we assess howreliable tsunami predictions obtained using physics-informed neural networksare and what the public perception of the reliability of such predictions is.

4

The waveform comparison of three fractional viscous acoustic wave equations

Wang Dan, Wang Zhiliang, Zhang Xinmin, Huang Rong, Song Ziang, Song Guojie

Acta Geophysica

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2025

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Vol. 73, no. 1

311--320

EN

The forward simulation of the viscous acoustic wave equation is essential for understanding wave propagation and seismic inversion. The viscous acoustic seismic wave equations are diverse, even if we limit the study scope to the fractional viscous wave equations. In present study, we consider three Riesz fractional viscous wave equations: the Fractional Viscous Acoustic Wave (FVAW) equation, Dispersion-Dominated Wave (DDW) equation, and Attenuation-Dominated Wave (ADW) equation. The Acoustic Wave (AW) equation, as a special fractional wave equation, is used to compare with the three fractional viscous acoustic equations. The Asymptotic Local Finite Difference (ALFD) method is adopted to solve the fractional derivative term; while, the Lax-Wendroff Correction (LWC) scheme is used to solve the integer derivative term. The analysis results indicate that the numerical scheme of the ADW equation exhibits the most rigorous stability condition, and that of the DDW equation is the most flexible. When the product of complex wavenumber k and spatial step size h equal to π, the maximum phase velocity errors of the FVAW equation, DDW equation, ADW equation, and AW equation are 27.78%, 28.02%, 2.25%, and 3.04%, respectively. Numerical experiments demonstrate that the FVAW equation not only governs the arrival time but also influences the amplitude. The DDW equation governs the arrival time but not amplitude; while, the ADW equation controls the amplitude but not arrival time. As the quality factor Q decreases, the viscous features of these three wave equations become pronounced. The change of amplitude is more noticeable than that of arrival time, suggesting that arrival time is more robust than amplitude. Based on these findings, we suggest incorporating the step for selecting the governing equations when dealing with practical Full-Waveform Inversion, which is helpful to improve the accuracy and reliability of the inversion results. Our results not only emphasize the importance of understanding the behavior of viscous wave equations, but also provide waveform evidence for selecting seismic governing equations in Full-Waveform Inversion.

5

Numerical modelling of the laser high-temperature hyperthermia using the dual-phase lag equation

Stryczyński Mikołaj, Majchrzak Ewa

Journal of Theoretical and Applied Mechanics

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2024

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Vol. 62 nr 2

389--401

EN

In the paper, thermal processes occurring in a soft tissue subjected to laser irradiation are analyzed. The bioheat transfer in an axisymmetric domain is described by a dual-phase lag equation, which takes into account temperature-dependent thermophysical parameters of the tissue. The source term in this equation is related to laser irradiation, and is determined by solving the optical diffusion equation. It is assumed that the optical parameters depend on the Arrhenius integral, which is a measure of the degree of tissue destruction. In the model, the process of evaporation of water contained in the tissue is also considered.

6

Heat transfer in a thin metal film subjected to the ultra-short laser pulse modeled by a nonlinear two-temperature model

Dziatkiewicz Jolanta, Majchrzak Ewa

Journal of Theoretical and Applied Mechanics

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2024

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Vol. 62 nr 2

403--413

EN

The heating of a thin metal film subjected to the ultra-short laser pulse is presented. Mathe- matical description of this process is based on the system of equations describing the electron and lattice temperatures and dependences between intensity of heat fluxes and temperature gradients supplemented by appropriate boundary and initial conditions. In this approach, a system of four equations needs to be solved. In this paper, another method of solution of the above formulated problem is proposed. Using appropriate mathematical manipulations, instead of four equations, two equations describing the lattice and electron temperature dis- tributions are obtained. This system of two equations is solved using an implicit scheme of the finite difference method. The results obtained using both approaches were compared. They were almost identical, which confirms the correctness of the proposed method.

7

Numerical simulation of oxygen distribution in soft tissue exposed to an external heat impulse

Zadoń Maria, Jasiński Marek

Journal of Applied Mathematics and Computational Mechanics

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2024

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Vol. 23, nr 4

133--144

EN

The purpose of this study is to analyse the effect of elevated temperature on oxygen distribution in biological tissue. The effect of temperature and thermal tissue damage on the values of thermophysical parameters was considered. Changes in the perfusion coefficient affect blood velocity in the capillary, thereby influencing the distribution of partial oxygen pressure. In the tissue area, the effect of myoglobin was taken into account. Furthermore, the effect of mitochondrial clustering on oxygen distribution was also analysed. The finite difference method and the shooting method were used in the numerical implementation stage.

8

Optimization of Rectangular Tank Cross-Section Using Trust Region Gradient Method

Grabowski Tomasz, Szymczak-Graczyk Anna, Rutkowski Janusz

Inżynieria Mineralna

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2024

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Vol. 1, no. 2

art. no. 99

EN

In various industries, rectangular tanks are commonly used for storing liquids and other materials. The design and optimization of these tanks are crucial for ensuring structural integrity and material efficiency. Traditional designs often utilize constant wall thickness, which does not align optimally with the stress distribution, leading to potential overuse of materials and increased costs. Recent studies have shown that tanks with variable wall thickness, such as trapezoidal cross-sections, can better match stress distributions, particularly under hydrostatic loads, resulting in more efficient use of materials. This research aims to build upon previous studies by introducing an advanced optimization algorithm based on the Trust Region Gradient Method to further refine the cross-sectional design of rectangular tanks. The primary objective is to minimize the material usage while maintaining structural safety and performance under various load conditions, including hydrostatic pressure and thermal effects. The proposed algorithm iteratively adjusts the tank's wall thickness, seeking an optimal configuration that reduces bending moments and material costs. Initial static calculations is verified using the finite difference method, emphasizing energy minimization conditions for elastic strain in bent plates on elastic foundations. This approach is compared with traditional discretization methods to validate accuracy. The trust region method is then applied to optimize the design, with a focus on achieving a balance between structural integrity and economic feasibility. Preliminary results indicate that the trust region gradient method can significantly enhance the design process, leading to substantial material savings and improved structural performance. The algorithm's effectiveness is demonstrated through case studies comparing tanks with constant and variable wall thickness. This research contributes to sustainable construction practices by promoting designs that use materials more efficiently and meet safety standards.

9

Influence of Geometric Parameters on Internal Forces in the Walls of Rectangular Tanks

Szymczak-Graczyk Anna, Grabowski Tomasz, Ksit Barbara

Inżynieria Mineralna

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2024

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Vol. 1, no. 2

art. no. 27

EN

Rectangular tanks are commonly used in various industries for storing materials and products. The design of reinforced concrete liquid tanks, which must be preceded by a static analysis, is a complex issue requiring specialized knowledge and engineering experience. All types of actions, design situations, and resulting load combinations must be considered, including deformations caused by temperature gradients and the interaction of the bottom plate with the ground. Most tanks are designed and constructed with constant wall thickness, regardless of their rectangular or circular cross-section. However, tanks with variable wall thickness (e.g., trapezoidal cross-section) are rarely designed, despite their optimal fit to stress distribution. For hydrostatically loaded tanks, the load on walls increases with depth, causing the highest bending moments at the wall-bottom connection, while the value at the top, free edge is zero. Thus, structural and economic considerations favour walls with thickness increasing with depth. This article presents the results of a verification of static calculations of a monolithic rectangular tank with trapezoidal cross-section walls, comparing it with three other commonly designed tanks with different thickness and wall designs. Static calculations were performed using the finite difference method in terms of energy, employing the condition for the minimum energy of elastic strain stored in a bent plate resting on the elastic base. Traditional calculation methods were used by discretizing the object and creating systems of equations. Analysis of the results shows that constructing walls of linearly variable thickness results in a redistribution of bending moments compared to tanks with uniform wall thickness. This significantly impacts the required reinforcement area. Tanks with linearly variable wall thickness are more economical in terms of material use, aligning with the principles of sustainable construction.

10

Hybrid Modelling Using Lattice Boltzmann and Finite Difference Methods of Dikes Effect on Sediment Transport and Morphological Processes with a Quasi-Tridimensional Approach

Machrouhi Khalil, Bendaraa Anass, Charafi My Mustapha, Hasnaoui Abdellatif

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 11

146--162

EN

This paper presents the development of a quasi-three-dimensional model that utilizes an equilibrium technique to investigate the morphological change of a channel focused on transport of sediment. The authors developed a computational algorithm that integrates two numerical techniques, specifically the Lattice Boltzmann Method (LBM) and the finite-difference method (FDM), to perform a hybrid calculation. The aforementioned algorithm was employed to investigate the impact of dykes on the dynamics of channel flow, sediment transport, and bed evolution. To derive the three-dimensional velocity field, the Boltzmann lattice method is employed to compute the two horizontal components of the vertically integrated velocity. Subsequently, these two components are combined with a logarithmic vertical profile. The process of sediment particle transport can be divided into two components: the bed load transport rate and the suspended load transport rate. The latter determination is achieved through the computation of the equilibrium flow rate of suspended sediment, which is derived from the equilibrium concentrations and logarithmic velocities. by comparing its outputs to previous research on constant width channels and horizontal beds, especially in dykes, the model was validated. This model accurately predicts sediment transport as bed load and suspended load, which is important for understanding sediment dynamics around such structures. the model’s ability to anticipate sediment erosion and deposition across the channel, providing crucial insights into river detours and other sedimentary processes.

11

Modeling of photochemical and photothermal effects in soft tissue subjected to laser irradiation

Jasiński Marek, Zadoń Maria

Computer Assisted Methods in Engineering and Science

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2024

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Vol. 31, no. 1

29--50

EN

The purpose of this study is to analyze the phenomena that occur in biological tissueduring photodynamic therapy (PDT). Under the influence of the laser, triplet oxygen istransformed into singlet oxygen, which is cytotoxic to cancer tissue. The impact of thelaser on the tissue may also be accompanied by changes in the thermophysical parameters,e.g., perfusion, which can affect the supply of oxygen to the tissue and, consequently,the outcome of the therapy. The proposed model uses the optical diffusion equation,the Pennes bioheat transfer equation, and reactions equations for PDT. The connectionbetween bioheat transfer and PDT models is taken into account through the respectiverelationships between perfusion rate, capillary blood velocity, and the maximum oxygensupply rate. Furthermore, a method is proposed to model abnormal vascular patterns inthe tumor subdomain. The boundary element method and the finite difference methodwere used in the numerical implementation stage.

12

Assessment of sinkhole hazard in the post-mining area using the ERT method and numerical modeling

Ścigała Roman, Szafulera Katarzyna, Jendryś Marek

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2023

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nr 75 (147)

20--34

EN

The loss of stability of shallow voids existing in the rock mass often results in the formation of sinkholes on the surface. This has a significant impact on the threat to public safety. Therefore, it is crucial to recognize the presence of such voids, especially in old post-mining areas, where shallow extraction was previously conducted, and there is a lack of mapping documentation indicating the location of underground workings. This paper presents an example illustrating a proposed procedure for recognizing shallow voids, which consists of two research works: geophysical research combined with numerical analyzes used as a kind of forward modeling. This combination increases the possibility of accurately locating potential sinkhole occurrences. The first part of this article provides selected literature information on the occurrence of sinkhole hazards. The second part presents the results of subsurface layer investigations of the rock mass conducted using electrical resistivity tomography (ERT). The third part focuses on assessing the threat of sinkhole formation by using forward numerical modeling performed with the FLAC 3D software to confirm the subsurface structures identified through the ERT method. The results of the analyzes conducted with both methods are then discussed in terms of their suitability for assessing the associated risk. The research conducted within the framework of this study confirms the effectiveness of the ERT method combined with numerical modeling for evaluating the state of the rock mass. This method can be considered a valuable tool for supporting decision-making in identifying post-mining areas that are particularly at risk of sinkhole formation.

13

The Temperature Field Effect on Dynamic Stability Response of Three-layered Annular Plates for Different Ratios of Imperfection

Pawlus Dorota

Studia Geotechnica et Mechanica

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2023

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Vol. 45, nr 2

158--173

EN

The paper presents the temperature field effect on the dynamic stability problem of plates with imperfection. The main objective is to conduct numerical investigations which show the relations between the imperfection ratio and plate dynamic response in a thermal environment. The plate is composed of three layers: thin facings and a thicker core. The plate can be loaded mechanically and thermally or only thermally. The facings are mechanically compressed with the forces acting in a plane. The temperature field model is defined by the temperature difference, which occurs between the plate edges. Two plate models are examined as follows: built using the approximation methods – orthogonalization and finite differences – and composed of finite elements. The analytical and numerical solution procedure is the main one, which is the proposal to perform the problem analysis. The plate reaction is described by the obtained values of the critical temperature differences for plates loaded only thermally and by the critical mechanical load sand the corresponding temperature differences for plates loaded mechanically and subjected to the uncoupled temperature field. The effect of the plate imperfection ratio under time-dependent loads is shown by numerous observations and results, which are shown graphically. The importance of the imperfection ratio on the plate’s dynamic stability response in complex loading conditions is studied.

14

A blow up of solutions for a system of Klein-Gordon equations with variable exponent : theoretical and numerical results

Gözen Sedanur Mazi, Yılmaz Nebi, Pişkin Erhan, Okutmustur Baver

Mathematica Applicanda

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2023

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Vol. 51, no. 2

143--164

EN

In this paper, we consider a system of Klein-Gordon equations with variable exponents. The first part of the manuscript is devoted to the proof of the blow up of solutions with negative initial energy under suitable conditions on variable exponents and initial data. The theoretical part is supported by numerical experiments based on P1-finite element method in space and the BDF and the Generalized-alpha methods in time illustrated in the second part. The numerical and analytical results of the blow up solutions agree with each other.

PL

Praca poświęcona jest układowi równań Kleina-Gordona ze zmiennymi wykładnikami. W pierwszej części pokazano, że rozwiązania o ujemnej energii początkowej uciekają do nieskończoności przy odpowiednich warunkach na wykładniki oraz dane początkowe. Część teoretyczną uzupełniają obliczenia numeryczne oparte na metodzie elementu skończonego dla zmiennych przestrzennych oraz metodzie różniczkowania wstecz (Backward Differentiation Formula, BDF). Wyniki numeryczne i analityczne dotyczące wybuchowego charakteru rozwiązań wzajemnie potwierdzają się.

15

Projektowanie obudowy tunelu z wykorzystaniem metody kontroli konwergencji

Blajer Mateusz

Materiały Budowlane

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2023

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nr 5

10--13

PL

W artykule przedstawiono wykorzystanie metody kontroli konwergencji do weryfikacji obudowy tunelu drążonego w warunkach fliszu karpackiego. Bazuje ona na obliczeniach numerycznych MES lub MRS i stanowi rozwinięcie metod analitycznych i seminumerycznych, które wykorzystywano w początkach jej stosowania. Dzięki użyciu modeli MES lub MRS możliwe jest odwzorowanie tak skomplikowanego ośrodka, jakim jest flisz karpacki i jego (w większości przypadków) asymetrycznego oddziaływania. Obecnie jedynie przestrzenne modele MES i MRS przewyższają opisywaną metodę pod względem możliwości obliczeniowych.

EN

The paper presents the use of the convergence confinement method for designing and verifying the tunnel lining in the conditions of the Carpathian flysch. It is based on numerical calculations using FEM or FDM and it is a development of the analytical and semi-analytical methods that were used at the beginning of its application. By using FEM or FDM models, it is possible to reproduce such a complex medium as the Carpathian flysch and its (mostly asymmetric) actions. Currently, only spatial FEM and FDM models exceed the described method in terms of computational capabilities.

16

Comparison of heat transfer phenomena for two different cryopreservation methods : slow freezing and vitrification

Skorupa Anna, Piasecka-Belkhayat Alicja

Journal of Applied Mathematics and Computational Mechanics

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2023

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Vol. 22, nr 1

57--69

EN

The purpose of the research is to prepare a mathematical and numerical model for the phenomenon of heat transfer during cryopreservation. In the paper, two popular methods, slow freezing and vitrification, are compared. Furthermore, the basic model of thermal processes is supplemented by the phenomenon of phase transitions. To determine the temperature distribution during cryopreservation processes, one uses the heat transfer equation proposed by Pennes. An integral part of the energy equation is the substitute thermal capacity (STC) performed according to the concept named one domain method (fixed domain method), The numerical model is developed using the finite difference method (FDM) connected with directed interval arithmetic. The final part of the article contains the results of numerical simulations.

17

The dynamic stability problem of composite annular plates with auxetic properties

Pawlus Dorota

Engineering Transactions

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2023

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Vol. 71, iss. 3

329--349

EN

This paper presents the effect of the auxeticity on the behaviour of a plate subjected to the loss of stability. The plate structure is composed of three layers built of auxetic or conventional facings and a conventional core. The plate is loaded mechanically in the plane of facings with forces increasing in time. The main technique of the problem solution is based on the orthogonalisation and finite differences methods. Selected examples of plates were calculated with the use of the finite difference method. The obtained results allow observing the similarities and differences between plate models, whose structures are built of conventional layers or mixed layers: auxetic-foam-auxetic. Investigations complement the knowledge of the responses of the composite structures with auxetic properties. They show the possibility of using special plate structures whose materials are characterised by the negative value of Poisson’s ratio.

18

Modeling of the influence of elevated temperature on oxygen distribution in soft tissue

Jasiński Marek, Zadoń Maria

Engineering Transactions

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2023

|

Vol. 71, iss. 3

287--306

EN

The purpose of the study was to analyze the combined model of bioheat transfer and oxygen distribution in tissue during exposition to the external heat impulse. The effect of temperature and thermal damage to the tissue on the values of its thermophysical parameters was taken into account. The variable value of the perfusion coefficient affects the blood velocity in the capillary and thus the distribution of the partial oxygen pressure in the tissue. Various models of the oxygen dissociation curves were also considered and a sensitivity analysis was performed for the parameters of the oxygen distribution model. In the numerical realization stage, the finite difference method and the shooting method were used.

19

Application of genetic algorithm for double-lap adhesive joint design

Kurennov Sergei, Barakhov Konstantin, Polyakov Olexander, Taranenko Igor

Archive of Mechanical Engineering

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2023

|

LXX, nr 1

27--42

EN

The problem of optimal design of symmetrical double-lap adhesive joint is considered. It is assumed that the main plate has constant thickness, while the thickness of the doublers can vary along the joint length. The optimization problem consists in finding optimal length of the joint and an optimal cross-section of the doublers, which provide minimum structural mass at given strength constraints. The classical Goland-Reissner model was used to describe the joint stress state. A corresponding system of differential equations with variable coefficients was solved using the finite difference method. Genetic optimization algorithm was used for numerical solution of the optimization problem. In this case, Fourier series were used to describe doubler thickness variation along the joint length. This solution ensures smoothness of the desired function. Two model problems were solved. It is shown that the length and optimal shape of the doubler depend on the design load.

20

Simulation of infeasible instruments in a sound synthesizer - implementation and control

Pluta Marek

Vibrations in Physical Systems

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2022

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Vol. 33, nr 2

art. no. 2022206

EN

Sound synthesis using mathematical modelling of musical instruments is a method particularly well suited for live performance using a physical controller. Depending on model complexity, it may be able to reproduce various subtle phenomena related to excitation and real time control of an instrument, providing an intuitive tool for a musician. A variant of physical modelling synthesis, referred to as the simulation of infeasible instruments, uses a model of an object that does not have a physical counterpart. Such model has some properties of a real object, which makes it still intuitive for a musician. However, other features, such as geometry, or material properties, are intentionally altered in such manner, that it could not function in reality. These infeasible features introduce new properties to the sound it produces. The study presents a few such models with a discussion regarding their implementation and control issues in a real-time sound synthesizer.