2021 - Publications Repository - Gdańsk University of Technology

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Publications from the year 2021

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On Fast Multi-objective Optimization of Antenna Structures Using Pareto Front Triangulation and Inverse Surrogates
- Anna Pietrenko-Dąbrowska
- Sławomir Kozieł
- Leifur Leifsson
2021
Design of contemporary antenna systems is a challenging endeavor, where conceptual developments and initial parametric studies, interleaved with topology evolution, are followed by a meticulous adjustment of the structure dimensions. The latter is necessary to boost the antenna performance as much as possible, and often requires handling several and often conflicting objectives, pertinent to both electrical and field properties of the structure. Unless the designer’s priorities are already established, multi-objective optimization (MO) is the preferred way of yielding the most comprehensive information about the best available design trade-offs. Notwithstanding, MO of antennas has to be carried out at the level of full-wave electromagnetic (EM) simulation models which poses serious difficulties due to high computational costs of the process. Popular mitigation methods include surrogate-assisted procedures; however, rendering reliable metamodels is problematic at higher-dimensional parameter spaces. This paper proposes a simple yet efficient methodology for multi-objective design of antenna structures, which is based on sequential identification of the Pareto-optimal points using inverse surrogates, and triangulation of the already acquired Pareto front representation. The two major benefits of the presented procedure are low computational complexity, and uniformity of the produced Pareto set, as demonstrated using two microstrip structures, a wideband monopole and a planar quasi-Yagi. In both cases, ten-element Pareto sets are generated at the cost of only a few hundreds of EM analyses of the respective devices. At the same time, the savings over the state-of-the-art surrogate-based MO algorithm are as high as seventy percent.
On FEM analysis of Cosserat-type stiffened shells. Static and stability linear analysis
- Stanisław Burzyński
2021 Full text CONTINUUM MECHANICS AND THERMODYNAMICS
The present research investigates the theory and numerical analysis of shells stiffened with beams in the framework based on the geometrically exact theories of shells and beams. Shell’s and beam’s kinematics are described by the Cosserat surface and the Cosserat rod respectively, which are consistent including deformation and strain measures. A FEM approximation of the virtual work principle leads to the conforming shell and beam FE with 6 DoFs (including the drilling rotation for shells) in each node. Examples of static and stability linear analyses are included. Novel design formulas for the stability of stiffened shells are included.
On forced vibrations of piezo-flexomagnetic nano-actuator beams
- Mohammad Malikan
- Victor Eremeev
2021
The effect of excitation frequency on the piezomagnetic Euler-Bernoulli nanobeam taking the flexomagnetic material phenomenon into consideration is investigated in this chapter. The magnetization with strain gradients creates flexomagneticity. We couple simultaneously the piezomagnetic and flexomagnetic properties in an inverse magnetization. Resemble the flexoelectricity, the flexomagneticity is also size-dependent. So, it has further notable influence at a small size. Here, a dynamic loading is transversely acted on the nanobeam. This loading plays the role of the excitation force. Moreover, we combine the equilibrium equations with the nonlocal model of strain gradient elasticity (NSGT). Afterward, we impose the Hamilton’s principle for having the governing equations. The attained linear differential equation is transferred into an algebraic equation by using Galerkin weighted residual method. Then, the gained linear algebraic equation is solved which leads to numerical values of dynamic deflections.
On geometry parameterization for simulation-driven design closure of antenna structures
- Sławomir Kozieł
- Anna Pietrenko-Dąbrowska
2021 Full text Scientific Reports
Full-wave electromagnetic (EM) simulation tools have become ubiquitous in antenna design, especially final tuning of geometry parameters. From the reliability standpoint, the recommended realization of EM-driven design is through rigorous numerical optimization. It is a challenging endeavor with the major issues related to the high computational cost of the process, but also the necessity of handling several objectives and constraints over often highly-dimensional parameter spaces. From the numerical perspective, making decisions about the formulation of the optimization problem, the approach to handling the design constraints, but also parameterization of the antenna geometry, are all non-trivial. At the same time, these issues are interleaved, and may play an important role in the performance and reliability of the simulation-based design closure process. This paper demonstrates that the approach to arranging the structure parameterization (e.g., the use of absolute or relative parameters) may have a major effect of the optimization outcome. Our investigations are carried out using three broadband monopole antennas optimized under different scenarios and using different parameterizations. In particular, the results indicate that relative parameterization is preferred for optimization of input characteristics, whereas absolute parameterization is more suitable for size reduction.
On Guard for Lighting Quality. The establishment of the first association of professional lighting designers
- Karolina Zielińska-Dąbkowska
2021 Full text ARC Lighting In Architecture
Not many people in the lighting community are aware of the fact, that after electricity was invented and in general use in the United States from the late nineteenth century, only electrical engineers were responsible for the illumination of architecture. After 1906, when the Illuminating Engineering Society of North America (IESNA) was established in the USA, companies and individuals professionally involved in the field of gas lighting and natural light, were first brought together. However, this new field quickly became dominated by people applying electric light in their projects. Members of this young discipline were mindful from the beginning, that a collaboration with architects was decisive and of great importance for the future development of lighting as a profession.
On nonlinear dilatational strain gradient elasticity
- Victor Eremeev
- Antonio Cazzani
- Francesco dell'Isola
2021 Full text CONTINUUM MECHANICS AND THERMODYNAMICS
We call nonlinear dilatational strain gradient elasticity the theory in which the specific class of dilatational second gradient continua is considered: those whose deformation energy depends, in an objective way, on the gradient of placement and on the gradient of the determinant of the gradient of placement. It is an interesting particular case of complete Toupin–Mindlin nonlinear strain gradient elasticity: indeed, in it, the only second gradient effects are due to the inhomogeneous dilatation state of the considered deformable body. The dilatational second gradient continua are strictly related to other generalized models with scalar (one-dimensional) microstructure as those considered in poroelasticity. They could be also regarded to be the result of a kind of “solidification” of the strain gradient fluids known as Korteweg or Cahn–Hilliard fluids. Using the variational approach we derive, for dilatational second gradient continua the Euler–Lagrange equilibrium conditions in both Lagrangian and Eulerian descriptions. In particular, we show that the considered continua can support contact forces concentrated on edges but also on surface curves in the faces of piecewise orientable contact surfaces. The conditions characterizing the possible externally applicable double forces and curve forces are found and examined in detail. As a result of linearization the case of small deformations is also presented. The peculiarities of the model is illustrated through axial deformations of a thick-walled elastic tube and the propagation of dilatational waves.
On possible applications of media described by fractional-order models in electromagnetic cloaking
- Tomasz Stefański
2021 Communications in Nonlinear Science and Numerical Simulation
The purpose of this paper is to open a scientific discussion on possible applications of media described by fractional-order (FO) models (FOMs) in electromagnetic cloaking. A 2-D cloak based on active sources and the surface equivalence theorem is simulated. It employs a medium described by FOM in communication with sources cancelling the scattered field. A perfect electromagnetic active cloak is thereby demonstrated with the use of a finite-difference time-domain method combined with a simulation algorithm of non-monochromatic wave propagation in the media described by FOM. The application of constitutive relations based on FOMs in Maxwell’s equations provides solutions which correspond to the results reported for the time-fractional diffusion-wave equation, which is non-relativistic, like the classical diffusion equation. This property is employed in the presented cloaking scheme for communication with active current sources around the cloak, which cancel the scattered field of an object inside the cloak. Although in the real world perfect invisibility is impossible to obtain due to the constraint of light speed, it is possible to obtain a perfect cloak in theoretical considerations by using FO formulation of electromagnetism. It is worth noticing that numerous literature sources experimentally confirm the existence of electromagnetic media described by FOMs; hence, the presented numerical results should hopefully stimulate further investigations related to applications of FOMs in electromagnetic cloaking.
On the Application of Magnetoacoustic Emission for a Nondestructive Assessment of the Post Welding Heat Treatment of High Chromium Steel Weld Seams
- Leszek Piotrowski
- Marek Chmielewski
- Grzegorz Golański
- K. Wojsyk
2021 Full text JOURNAL OF NONDESTRUCTIVE EVALUATION
The paper analyses the possibility of post weld heat treatment (PWHT) quality assessment with the help of magnetoacoustic emission (MAE) signal measurements. Two welded superheater tubes, made of high chromium VM12 steel, were analysed—as welded and heat treated one. The analysed sample in the as welded state exhibited significantly higher hardness, accompanied by a big difference in the MAE signal intensity (of order of about 50%). In order to explain that, the influence of tempering on the MAE signal intensity is demonstrated for the very similar X20CrMoV12.1 steel. It is shown that the observed increase of the MAE intensity as a function of annealing time is directly correlated with the change in hardness. The as described dependence allows to propose a method based on the MAE signal measurements as a new tool for the PWHT assessment.
On the Characteristic Graph of a Discrete Symmetric Channel
- Dariusz Dereniowski
- Marcin Jurkiewicz
2021 IEEE TRANSACTIONS ON INFORMATION THEORY
We present some characterizations of characteristic graphs of row and/or column symmetric channels. We also give a polynomial-time algorithm that decides whether there exists a discrete symmetric channel whose characteristic graph is equal to a given input graph. In addition, we show several applications of our results.
On the current state of dovetail wall-corner joints in wooden Greek Catholic churches in Polish Subcarpathia with structural and sensitivity analyses
- Izabela Lubowiecka
- Tomasz Zybała
- Grzegorz Bukal
- Marcin Krajewski
- Marcin Kujawa
- Paweł Kłosowski
2021 Full text International Journal of Architectural Heritage
This paper describes the current condition of some dovetail joints which form the wall corners of two Greek Catholic churches of wooden construction in Polish Subcarpathia. It also gives the historical background of the sacral architecture of that region. The two structures, which represent the same type of log corner joints are situated in Chotylub and Cewków. The buildings were examined e.g. for damage, wood moisture content, out-of-plane deviations and changes in the geometry of the walls. The study is based on in-situ examination and structural analysis of the joints. Finite element simulations of the statics of joints built of old, and mixture of old and new, wood are performed in order to show how the change of material properties affects their structural behaviour. Also a sensitivity analysis is performed to describe the effect on potential repairs that combining old damp wood with new and dry joint members might have.
On the generalized model of shell structures with functional cross-sections
- Shahriar Dastjerdi
- Mohammad Malikan
- Victor Eremeev
- Bekir Akgöz
- Ömer Civalek
2021 Full text COMPOSITE STRUCTURES
In the present study, a single general formulation has been presented for the analysis of various shell-shaped structures. The proposed model is comprehensive and a variety of theories can be used based on it. The cross-section of the shell structure can be arbitrarily analyzed with the presented equations. In other words, various types of shell structures, including cylindrical, conical, spherical, elliptical, hyperbolic, parabolic, and any non-geometric structure with functional cross-section, can be modeled mechanically with only one partial differential equation system. The obtained equations have been solved by applying SAPM semi-analytical solution method. In order to present a comprehensive research, dynamic nonlinear analysis is considered. The variation of material properties through the thickness has been assumed as functionally graded and its effect on the strength of the shell structure with the functional cross-section has been investigated. The numerical results have been compared with available papers and also with FEM results for some structures that there is no paper available for validation. Different types of shell structures have been studied in terms of cross-sectional shape and properties. Finally, the effects of some important factors on the results such as boundary conditions, nonlinear analysis, dynamic analysis, and rotation of the structure around its central axis have been conducted thoroughly. This study and its original governing equations can be considered as a comprehensive reference for mechanical analysis of various shell structures with functional cross-sectional shape.
On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
- Gennadi Mikhasev
- Marina Botogova
- Victor Eremeev
2021 Full text INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
We discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present the dependence of the wave amplitude on the roughness magnitude. The presented results could be used for non-destructive evaluation of the surface microstructure using surface waves-based devices. In particular, measuring the decay rate with the depth one can estimate roughness of a surface and appearance of new surface defects.
On the mechanism of photocatalytic reactions on CuxO@TiO2 core–shell photocatalysts
- Kunlei Wang
- Zuzanna Bielan
- Maya Endo-Kimura
- Marcin Janczarek
- Dong Zhang
- Damian Kowalski
- Anna Zielińska-Jurek
- Agata Markowska-Szczupak
- Bunsho Ohtani
- Ewa Kowalska
2021 Journal of Materials Chemistry A
Titania (titanium(IV) oxide) is a highly active, stable, cheap and abundant photocatalyst, and is thus commonly applied in various environmental applications. However, two main shortcomings of titania, i.e., charge carrier recombination and inactivity under visible-light (vis) irradiation, should be overcome for widespread commercialization. Accordingly, titania has been doped, surface modified and coupled with various ions/compounds, including narrower bandgap semiconductors, such as oxides of copper and silver. Unfortunately, these oxides are not as stable as titania, and thus loss of activity under long-term irradiation (photo-corrosion) has been observed. Therefore, this study has focused on the preparation of stable coupled photocatalysts, i.e., CuxO@TiO2 core–shell nanostructures, by the microemulsion method from commercial Cu2O as a core and TiO2 (ST01-fine anatase) as a shell. The photocatalysts have been characterized by DRS, SEM, TEM, XRD, XPS and reversed double-beam photo-acoustic spectroscopy (RDB-PAS) methods, and activity tests under UV (anaerobic dehydrogenation of methanol and oxidative decomposition of acetic acid) and vis (phenol oxidation) irradiation. The higher activities of coupled photocatalysts than their counterparts have been found in all studied systems under UV/vis irradiation. Moreover, long-term experiments (10 h) have shown high stability of CuxO@TiO2. However, the change of oxidation state of copper has also been observed, i.e., to negative and positive values, confirming the charge transfer according to the Z-scheme under UV irradiation and type-II heterojunction under vis irradiation, respectively. The property-governed activity and the mechanism have been discussed in detail.
On the problem of optimised allocation of water quality sensors and actuators in DWDS
- Tomasz Zubowicz
- Rafał Łangowski
2021 Full text
The problems of water quality sensors and actuators placement in drinking water distribution systems (DWDSs) are addressed as separate, primarily. However, against the background of control systems theory, the nature of DWDSs dynamics indicates that these both problems are interdependent and impact the design of related water quality monitoring and control structures and algorithms. The research work presented in this paper is to investigate the state-of-the-art in this field and discuss the problems of water quality sensors and actuators placement within DWDS and to highlight the potential benefits of considering the joint task of their allocation.
On thermal stability of piezo-flexomagnetic microbeams considering different temperature distributions
- Mohammad Malikan
- Tomasz Wiczenbach
- Victor Eremeev
2021 Full text CONTINUUM MECHANICS AND THERMODYNAMICS
By relying on the Euler–Bernoulli beam model and energy variational formula, we indicate critical temperature causes in the buckling of piezo-flexomagnetic microscale beams. The corresponding size-dependent approach is underlying as a second strain gradient theory. Small deformations of elastic solids are assessed, and the mathematical discussion is linear. Regardless of the pyromagnetic effects, the thermal loading of the thermal environment varies in three states along with the thickness, which is linear, uniform, and parabolic forms. We then establish the results by developing consistent shape functions that independently evaluate boundary conditions. Next, we analytically develop and explore the effective properties of the studied beam concerning vital factors. It was achieved that piezomagnetic-flexomagnetic microbeams are more affected by the thermal environment while the thermal loading is parabolically distributed across the thickness, particularly when the boundaries involve simple supports.
On thio‐substituted N‐heterocyclic arsines
- Johannes Bender
- Agnieszka Skowrońska
- Anna Dołęga
- Martin Nieger
- Dietrich Gudat
2021 Full text ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
Metathesis of N-heterocyclic chloroarsines with sulfur-based nucleophiles furnished thio-substituted 1,3,2-diazarsolidines and 1,3,2-diazarsolenes. Crystallographic and NMR spectroscopic studies revealed that a thiocyanato-diazarsolene exhibits a salt-like structure composed of weakly interacting thiocyanate and arsenium ions, while the remaining products formed neutral molecules. The structural data indicate that the heterocyclic framework induces an elongation of exocyclic As−S bonds that is more prominent in diazarsolenes than in diazarsolidines and parallels the bond polarisation effect established for N-heterocyclic phosphines. The NMR data suggest that diazarsolenes undergo facile inversion of the pyramidal configuration at arsenic, which was successfully modelled by DFT studies.
On topology optimization of large deformation contact-aided shape morphing compliant mechanisms
- Prabhat Kumar
- Roger Sauer
- Anupam Saxena
2021 Full text MECHANISM AND MACHINE THEORY
A topology optimization approach for designing large deformation contact-aided shape morphing compliant mechanisms is presented. Such mechanisms can be used in varying operating conditions. Design domains are described by regular hexagonal elements. Negative circular masks are employed to perform dual task, i.e., to decide material states of each element and also, to generate rigid contact surfaces. Each mask is characterized by five design variables, which are mutated by a zero-order based hill-climbing optimizer. Geometric and material nonlinearities are considered. Continuity in normals to boundaries of the candidate designs is ensured using a boundary resolution and smoothing scheme. Nonlinear mechanical equilibrium equations are solved using the Newton–Raphson method. An updated Lagrange approach in association with segment-to-segment contact method is employed for the contact formulation. Both mutual and self contact modes are permitted. Efficacy of the approach is demonstrated by designing four contact-aided shape morphing compliant mechanisms for different desired curves. Performance of the deformed profiles is verified using a commercial software. The effect of frictional contact surface on the actual profile is also studied.
On weak solutions of boundary value problems within the surface elasticity of Nth order
- Victor Eremeev
- Leonid Lebedev
- Michael Cloud
2021 ZAMM-Zeitschrift fur Angewandte Mathematik und Mechanik
A study of existence and uniqueness of weak solutions to boundary value problems describing an elastic body with weakly nonlocal surface elasticity is presented. The chosen model incorporates the surface strain energy as a quadratic function of the surface strain tensor and the surface deformation gradients up to Nth order. The virtual work principle, extended for higher‐order strain gradient media, serves as a basis for defining the weak solution. In order to characterize the smoothness of such solutions, certain energy functional spaces of Sobolev type are introduced. Compared with the solutions obtained in classical linear elasticity, weak solutions for solids with surface stresses are smoother on the boundary; more precisely, a weak solution belongs to 1()∩() where ⊂≡ and ⊂ℝ3 .
On Wrinkling in Sandwich Panels with an Orthotropic Core
- Zbigniew Pozorski
- Jolanta Pozorska
- Ireneusz Kreja
- Łukasz Smakosz
2021 Full text Materials
This paper deals with the local loss of stability (wrinkling) problem of a thin facing of a sandwich panel. Classical solutions to the problem of facing instability resting on a homogeneous and isotropic substructure (a core) are compared. The relations between strain energy components associated with different forms of core deformations are discussed. Next, a new solution for the orthotropic core is presented in detail, which is consistent with the classic solution for the isotropic core. Selected numerical examples confirm the correctness of the analytical formulas. In the last part, parametric analyses are carried out to illustrate the sensitivity of wrinkling stress to a change in the material parameters of the core. These analyses illustrate the possibility of using the equations derived in the article for the variability of Poisson’s ratio from -1 to 1 and for material parameters strongly deviating from isotropy.
Onboard Energy Storage and Power Management Systems forAll-Electric Cargo Vessel Concept
- Dariusz Karkosiński
- Wojciech Aleksander Rosiński
- Piotr Deinrych
- Szymon Potrykus
2021 Full text ENERGIES
This paper presents an innovative approach to the design of a forthcoming, fully electric-powered cargo vessel. This work begins by defining problems that need to be solved when designingvessels of this kind. Using available literature and market research, a solution for the design of apower management system and a battery management system for a cargo vessel of up to 1504 TEUcapacity was developed. The proposed solution contains an innovative approach with three parallelenergy sources. The solution takes into consideration the possible necessity for zero-emission workwith the optional function of operation as an autonomous vessel. Energy storage system based onlithium-ion battery banks with a possibility of expanding the capacity is also described in this work asit is the core part of the proposed solution. It is estimated that the operation range for zero-emissionwork mode of up to 136 nautical miles can be achieved through the application of all fore-mentioned parts.