Filters
total: 8561
filtered: 6883
-
Catalog
- Publications 6883 available results
- Journals 269 available results
- Conferences 12 available results
- People 240 available results
- Inventions 3 available results
- Projects 6 available results
- Research Teams 1 available results
- e-Learning Courses 208 available results
- Events 6 available results
- Open Research Data 933 available results
Chosen catalog filters
displaying 1000 best results Help
Search results for: structural%20mechanics
-
Probabilistic sensitivity of the limit states of structures using Monte Carlom simulation
PublicationThe paper presents the concept of probabilistic sensitivity of structural limit states with respect to given design variables. A general idea is presented, illustrated by a simple case solved in an analytical way. More general approach is presented for the engineering structures, in this case a dedicated Monte Carlo simulation procedure is involved as part of the methodology. Illustration of the engineering case is done, by means...
-
Study of structures and properties of the laser cladding exhaust valve after service
PublicationPrzylgnie zaworów wydechowych silnie obciążonego silnika okrętowego zostały pokryte warstwą wykonana ze stopu kobaltu za pomocą techniki napawania laserowego. Tak przygotowane zawory były eksploatowane przez 3000 godzin w silniku Daru Młodzieży. Po tym czasie zostały zdemontowane i poddane szczegółowej analizie. Warunki pracy spowodowały powstanie na powierzchni przylgni warstwy tlenków o różnej grubości, wykazującej skłonność...
-
Local ordering of nano-structured Pt probed by multiple-scattering XAFS
PublicationW pracy przedstawiono wyniki analizy MS EXAFS krystalicznej platyny i nanostruktur platyny (klastry o rozmiarach od 1nm do 7nm). Rezultaty analizy masowej platyny (uwzględniające rozkłady dwu i trój-ciałowe) są zgodne z wcześniejszymi danymi strukturalnymi i wibracyjnymi i stały się podstawą do realistycznej analizy EXAFS nanocząstek Pt realizownej w połączeniu z wynikami pomiarów TEM, SEM i XRD. Badaniom poddano nanocząstki Pt...
-
Accurate modelling of microwave structures using shape-preserving response prediction
PublicationArtykuł prezentuje metodologię dokładnego modelowania struktur mikrofalowych. Jest to zmodyfikowana wersja techniki opartej na procedurze przewidywania odpowiedzi z zachowaniem kształtu (shape-preserving response prediction, SPRP), która oszacowuje odpowiedź struktury mikrofalowej otrzymanej poprzez kosztowną obliczeniowo symulację elektromagnetyczną za pomocą taniego obliczeniowo modelu tejże struktury. Modyfikacja polega na wykorzystaniu...
-
Novel microstrip low-pass filters with fractal defected ground structures
PublicationIn this study, three microstrip low-pass filters (LPFs) containing fractal-shaped defected ground structures have been designed and manufactured. To improve the performance of microstrip LPF, cascades of inductively coupled fractal resonators have been applied. Simultaneously, to achieve relatively constant microstrip impedance resulting in essentially low reflection losses, a modification of the strip geometry has been introduced....
-
A concept of an application to plan the time lines of building selected bridge structures
PublicationW rozdziale został przedstawiony przykład autorskiego programu komputerowego przeznaczonego do planowania czasu pracy i kosztów w budownictwie mostowym. Zaletą programu jest możliwość przedstawienia wyników w formie graficznej w sposób deterministyczny i niedeterministyczny. Ma to ogromne znaczenie jeżeli poszukujemy optymalnych rozwiązań dotyczących zagadnień ryzyka i ekonomiki budownictwa.
-
Prefabricated structures under earthquake excitation: damage and failure of connection joints
PublicationCelem artykułu jest analiza zachowania się złączy pomiędzy elementami belkowymi a słupami w konstrukcjach prefabrykowanych poddanych obciążeniom dynamicznym powstającym podczas trzęsień ziemi. Wyniki przedstawione w pracy, uzyskane na podstawie badań numerycznych przeprowadzonych dla wybranego modelu konstrukcji, pokazują, iż złącza są najsłabszym elementem wymagającym zwrócenia szczególnej uwagi przy projektowaniu konstrukcji...
-
Wave propagation modelling in 1D structures using spectral finite elements
PublicationW artykule omówiono modele propagacji fal wzdłużnych i poprzecznych w prętach oparte na dwóch sformułowaniach (w dziedzinie częstości i w dziedzinie czasu) metody elemntów spektralnych. Porównano otrzymane wyniki z wynikami eksperymentu.
-
The use of response surface methodology for reliability estimation of composite engineering structures
Publication -
Application of decision–making parametric structures in the analysis of a compound planetary gear
Publication -
An Approximate Linear Analysis of Structures Utilizing Incremental Loading of Force Method
Publication -
An Experimental Study on the Effect of Temperature on Acoustic Emission Characteristics in Metallic Structures
Publication -
Influence of sulphur on high temperature degradation of steel structures in the refinery industry
PublicationArtykuł stanowi przegląd skutków wpływu związków siarki, znajdujących się w mediach procesowych instalacji rafineryjnych, na elementy konstrukcji ze stali węglowych i stopowych. Wyróżniono dwa aspekty wysokotemperaturowej korozji siarkowej: związany z tworzeniem się zgorzeliny siarczkowej i ubytkami masy oraz dotyczący wewnętrznej degradacji elementu w wyniku zmian mikrostruktury stali. Przedstawiono tzw. zmodyfikowane krzywe McConomy...
-
The K X-ray line structures for a warm dense copper plasma
Publication -
Double amino acid – A novel molecule enabling peptide interpenetrating structures
Publication -
Global dynamics in a stage-structured discrete-time population model with harvesting
Publication -
CAVER 3.0: A Tool for the Analysis of Transport Pathways in Dynamic Protein Structures
Publication -
A higher order shell element for wave propagation in isotropic shell structures
PublicationThe presents the new multi mode higher order shell element for wave propagation problems in shell structures.
-
Design and implementation principles of FIReWORK ONLINE - the VHDL autogenerator for hardware structures
PublicationThe paper presents an aspects of remote autogeneration of hardware structures. The solution is an online application, that is running on the server side and allows to design a particular filters and other selected hardware and generate its structure in the form of VHDL, dedicated to FPGA design environments. The paper also addresses the problem of parameterization of algorithms used to generate the hardware structures and current...
-
The use of Response Surface Methodology for reliability estimation of composite engineering structures
PublicationStability loss is one of the key issues in the analysis of shells made of composite materials. This paper aims at finding the variation of the critical or limit value of the load resulting from geometric imperfections. An axially compressed 16-layer cylindrical panel model is considered. The imperfections of the panel are simulated as random fields. The parameters of these fields are used as the basic variables of the reliability...
-
Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
PublicationIn the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including...
-
Nitrogen mass balance and mathematical model of a Structured- Bed Reactor (SBRRIA)
PublicationAn up-flow structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) was operated under varying influent conditions. The influent COD/N ratio was adjusted by maintaining a stable organic loading rate (average of 1.07 kgCOD m-3 d-1) and changing the nitrogen loading rate from 0.1 to 0.4 kg N m-3. Therefore, three different COD/N ratios were tested: 9.7±1 (Scenario 1); 7.6±1 (Scenario 2) and 2.9±1 (Scenario...
-
Problems of collisions between adjacent steel structures under earthquake excitation
PublicationNowadays, the high level of urbanization forces the designers to design closely-separated structures and to take into account many factors influencing the response of these structures, which may collide due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as numerical and experimental investigations have confirmed that the interactions between structures may lead to significant...
-
Advanced Control Structures of Turbo Generator System of Nuclear Power Plant
PublicationIn the paper a synthesis of advanced control structures of turbine and synchronous generator for nuclear power plant working under changing operating conditions (supplied power level) is presented. It is based on the nonlinear models of the steam turbine and synchronous generator cooperating with the power system. Considered control structure consists of multi-regional fuzzy control systems with local linear controllers, including...
-
Guided waves for monitoring of plate structures with linear cracks of variable length
PublicationDamage occurring at the work of plate structures may grow to a considerable size. The joint action – the detection of a defect at the earliest possible stage, the monitoring of its growth and the determination of its critical size in the context of structural reliability allows optimizing the cost of the maintenance and repair of structural elements. Thus the development of monitoring systems for permanent observation of fault...
-
Lightweight glass and metal roof structures in the 19th century. Architecture and construction.
PublicationThe 19th century brought new construction possibilities. The usage of metal elements in mesh structures, filled in with glass, resulted in creating entirely new types of objects. They have distinguished themselves in architecture and technical solutions. The envelope structures giving spatial interiors were arising very quickly. They have been enabling large light penetration, triggering them extremely bright. Thus these building...
-
On Reduced-Cost Design-Oriented Constrained Surrogate Modeling of Antenna Structures
PublicationDesign of contemporary antenna structures heavily relies on full-wave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional data-driven...
-
Accurate simulation-driven modeling and design optimization of compact microwave structures
PublicationCost efficient design optimization of microwave structures requires availability of fast yet reliable replacement models so that multiple evaluations of the structure at hand can be executed in reasonable timeframe. Direct utilization of full-wave electromagnetic (EM) simulations is often prohibitive. On the other hand, accurate data-driven modeling normally requires a very large number of training points and it is virtually infeasible...
-
PROBLEMS OF COLLISIONS BETWEEN ADJACENT STEEL STRUCTURES UNDER EARTHQUAKE EXCITATION
PublicationNowadays, the high level of urbanization forces the engineers to design closely-separated structures and to take into account many factors influencing their response, including collisions between them due to insufficient separation distance during moderate to strong ground motions. Recent observations as well as experimental and numerical investigations have confirmed that interactions...
-
Efficient analysis of structures with rotatable elements using model order reduction
PublicationThis paper presents a novel full-wave technique which allows for a fast 3D finite element analysis of waveguide structures containing rotatable tuning elements of arbitrary shapes. Rotation of these elements changes the resonant frequencies of the structure, which can be used in the tuning process to obtain the S-characteristics desired for the device. For fast commutations of the response as the tuning elements are rotated, the...
-
Performance-driven yield optimization of high-frequency structures by kriging surrogates
PublicationUncertainty quantification is an important aspect of engineering design, as manufacturing toler-ances may affect the characteristics of the structure. Therefore, quantification of these effects is in-dispensable for adequate assessment of the design quality. Toward this end, statistical analysis is performed, for reliability reasons, using full-wave electromagnetic (EM) simulations. Still, the computational expenditures associated...
-
Optimized Stress and Geometry Control of Spherical structures under Lateral Loadings
PublicationIn this paper, a numerical model of a double-layer spherical structure has been examined under lateral loadings. When the structure has been distorted due to loadings, the dislocated joints have been moved to their original positions utilizing the adjustment techniques based on the force method. Meanwhile, the members’ internal forces were kept in the desired domain. Optimization techniques were also implemented in order to minimalize...
-
A coarse‐grained approach to NMR ‐data‐assisted modeling of protein structures
PublicationThe ESCASA algorithm for analytical estimation of proton positions from coarse-grained geometry developed in our recent work has been implemented in modeling protein structures with the highly coarse-grained UNRES model of polypeptide chains (two sites per residue) and nuclear magnetic resonance (NMR) data. A penalty function with the shape of intersecting gorges was applied to treat ambiguous distance restraints, which automatically...
-
A Stabilized Complex LOBPCG Eigensolver for the Analysis of Moderately Lossy EM Structures
PublicationThis letter proposes a stabilized locally optimal block preconditioned conjugate gradient method for computing selected eigenvalues for complex symmetric generalized non-Hermitian eigenproblems. Effectiveness of the presented approach is demonstrated for a moderately lossy dual-mode dielectric resonator, modeled using finite-element method with higher order elements
-
Path-based methods on categorical structures for conceptual representation of wikipedia articles
PublicationMachine learning algorithms applied to text categorization mostly employ the Bag of Words (BoW) representation to describe the content of the documents. This method has been successfully used in many applications, but it is known to have several limitations. One way of improving text representation is usage of Wikipedia as the lexical knowledge base – an approach that has already shown promising results in many research studies....
-
Calculation of Resonance in Planar and Cylindrical Microstrip Structures Using a Hybrid Technique
PublicationA hybrid technique was employed for the analysis of the resonance frequency of thin planar and cylindrical microstrip structures with the patches of arbitrary geometry. The proposed technique utilizes a combination of Galerkin’s moment method and a finite-element method (FEM). In this approach, an FEM is adopted to calculate the patch surface current densities, and a method of moments is utilized to calculate the resonance frequencies...
-
Evaluation of the structures size in the liquid-gas flow by gamma-ray absorption
PublicationThe rapid development of tomography methods particularly electrical, X and gamma rays allows for a wide range of the information about flow structure. However, all of such methods are quite complicated. At the same time much simpler systems as the measuring system of gamma rays absorption, allows to obtain a all key flow information which describe the two-phase flow. In the article the results of analyzes of radiometric signal...
-
Numerical modelling of moored floating structures using SPH. Preliminary results
PublicationThis article presents partial results of the works carried out under the research project "The development of the methodof modeling the dynamics of the floating (offshore) objects subjected to the environment influence", which aims at developing computational methods for modeling the dynamics of offshore structures.The article contains the description of the method of modeling the hydrodynamic impacts using SPH method and the description...
-
Robust Parameter Tuning of Antenna Structures by Means of Design Specification Adaptation
PublicationParameter tuning through numerical optimization has become instrumental in the design of high-performance antenna systems. Yet, practical optimization faces several major challenges, including high cost of massive evaluations of antenna characteristics, normally involving full-wave electromagnetic (EM) analysis, large numbers of adjustable variables, the shortage of reasonable initial solutions in the case of topologically complex...
-
On EM-driven size reduction of antenna structures with explicit constraint handling
PublicationSimulation-driven miniaturization of antenna components is a challenging task mainly due to the presence of expensive constraints, evaluation of which involves full-wave electromagnetic (EM) analysis. The recommended approach is implicit constraint handling using penalty functions, which, however, requires a meticulous selection of penalty coefficients, instrumental in ensuring optimization process reliability. This paper proposes...
-
Application of lightweight cement composite with foamed glass aggregate in shell structures
PublicationThe purpose of the paper is to investigate the abilities of applying Granulated Expanded Glass Aggregate (GEGA) as a natural volume substitute of aggregate as a component of lightweight concrete. The GEGA aggregates used in the experiments were made of confused glass waste. In order to achieve satisfactory strength of concrete Granulated Ash Aggregate (GAA) was added as well. To produce specimens three grain sizes of aggregates...
-
Guided Wave Propagation in Detection of Partial Circumferential Debonding in Concrete Structures
PublicationThe following article presents results of investigating the damage detection in reinforced concrete beams with artificially introduced debonding between the rod and cover, using a non-destructive method based on elastic waves propagation. The primary aim of the research was to analyze the possible use of guided waves in partial circumferential debonding detection. Guided waves were excited and registered in reinforced concrete...
-
Electrochemical behavior of a composite material containing 3D-structured diatom biosilica
Publication3D-structured diatom biosilica mixed with conducting carbon black was investigated as an active electrode material for lithium-ion batteries. Diatom biosilica was obtained by cultivation of the selected diatom species under laboratory conditions. Several instrumental techniques (XRD, FTIR, Raman, SEM-EDX, TGA) were used to characterize the physicochemical properties of applied biosilica. It was evidenced that the prepared new composite...
-
X-RAY DIFFRACTION STUDY OF BISMUTH LAYER-STRUCTURED MULTIFERROIC CERAMICS
PublicationGoal of the present research was to apply a solid state reaction route to fabricate bismuth layer-structured multiferroic ceramics described with the formula Bi5FeTi3O15 and reveal the influence of processing conditions on its crystal structure and phase composition. Simple oxide powders Bi2O3, TiO2 and Fe2O3 were used to fabricate Aurivillius-type bismuth layer-structured ferroelectrics. Pressureless sintering in ambient air was...
-
Recent Advances in Performance-Driven Surrogate Modeling of High-Frequency Structures
PublicationDesign of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of...
-
Scattering and Propagation Analysis for the Multilayered Structures Based on Field Matching Technique
PublicationA semi-analytical method is employed to the analysis of scattering and guiding problems in multilayer dielectric structures. The approach allows to investigate objects with arbitrary convex cross section and is based on the direct field matching technique involving the usage of the field projection at the boundary on a fixed set of orthogonal basis functions. For the scattering problems the scattered field in the far zone is calculated...
-
Topological modifications for performance improvement and size reduction of wideband antenna structures
PublicationCompact antennas belong to the key components of modern communication systems. Their miniaturization is often achieved by introducing appropriate topological changes such as simple ground plane slots or tapered feeds. More sophisticated modifications are rarely considered in the literature because they normally lead to significant increase of the number of tunable parameters, which makes the antenna design process more challenging....
-
Centralized and Distributed Structures of Intelligent Systems for Aided Design of Ship Automation
PublicationA design process and accepted solutions made during this process, often base on non-formalized knowledge, obtained from designer (expert) intuition and practice. There are no formalized rules assuring the correctness of design solutions. The analysis of design process of ship automation, including ship power system, shows that this process can be supported by application of the artificial intelligence elements. The article presents...
-
Environmental aspects of coastal earth structures made of soil-ash composites
PublicationThis paper presents an innovative technology of building the coastal dams with the use of soil-ash composites. A natural- scale test stand and results of the performed environmental tests are presented ; they have been compared with standards for purity of soils and waters. Also, an analysis of the obtained results and discussion of trends and anomalies in the observations, are given.
-
Investigation of behaviour of metal structures with polymer dampers under dynamic loads
PublicationA large number of accidents concerning structures subjected to dynamic loads have been recently observed. One of the examples of such a structure is a temporary steel grandstand erected using scaffolding system. Dynamic load that is generated by crowd movement has a significant influence on the behaviour of the structure and may lead to excessive structural vibrations. The aim of the study is to consider the idea of using polymer...