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Search results for: MINIATURIZED MICROWAVE STRUCTURES
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A novel microstrip dual-layer rat-race coupler with compact size and enhanced bandwidth
PublicationMicrowave hybrid couplers are crucial components of mixers, phase shifters, amplifiers and other high-frequency systems. Conventional couplers are characterized by large size which limits their usefulness in modern applications. In this work, a novel compact rat-race coupler with enhanced bandwidth has been proposed. The structure consists of six compact microstrip resonant cells. It is implemented on two separate layers which permits...
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Inverse Nonlinear Eigenvalue Problem Framework for the Synthesis of Coupled-Resonator Filters With Nonresonant Nodes and Arbitrary Frequency-Variant Reactive Couplings
PublicationA novel, general circuit-level description of coupledresonator microwave filters is introduced in this article. Unlike well-established coupling-matrix models based on frequency-invariant couplings or linear frequency-variant couplings (LFVCs), a model with arbitrary reactive frequencyvariant coupling (AFVC) networks is proposed. The engineered formulation is more general than prior-art ones—with the only restriction that the coupling...
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Serce dzielnicy w stanie embrionalnego rozwoju - śrómieście reurbanizowanego wielkiego osiedla w polskim mieście metropolitalnym = Heart of the districts in embrional faze of development -city core structures for the large scale housing in Polish metropolitan city
PublicationW ostatnich 10 latach obserwowana jest intensyfikacja procesu uzupełniania zabudowy śródmieścia Gdańska. Jest to z jednej strony kontynuacja odbudowy historycznego centrum miasta, z drugiej zaś rewitalizacja dzielnic o przewadze zabudowy z początku wieku obejmująca śródmiejskie tereny powojskowe i poprzemysłowe m.in dawnej Stoczni Gdańskiej, koszaty we Wrzeszczu. Liczne komercyjne projekty prowadzą do istotnych dogęszczeń funcjami...
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Zalecenia Komitetu Roboczego ''Konstrukcje Nadbrzeżne, Porty i Drogi Wodne, EAU 2004'' (wersja cyfrowa i uaktualniona 2009) = Recommendations of the Committee for Waterfront Structures Harbours and Waterways, EAU 2004 (Digitized and updated version 2009)
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Lower rim substituted tert-butylcalix[4]arenes (II). Complexing ability of5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-O-(piperidinylcarbonyl)me- thylenecalix[4]arene. The crystal structures of the ligand and its sodium complex
PublicationSyntezowano kompleksy wymienionego w tytule liganda z chlorkiem sodu i azotanami itru(III), lantanu(III), samaru(III) i gadolinu(III) w reakcji liganda i odpowiedniej soli, które charakteryzowano za pomocą widm IR, UV-vis,1H NMR, FAB-MS, a także za pomocą analizy elementarnej. W reakcji wymiany z kompleksu z sodem otrzymywano kompleksy z lantanowcami. Określono strukturę krystaliczną wolnego liganda i jego kompleksu z sodem za...
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Spurious Modes in Model Order Reduction in Variational Problems in Electromagnetics
PublicationIn this work, we address an everlasting issue in 2 model order reduction (MOR) in electromagnetics that has 3 remained unnoticed until now. Contrary to what has been 4 previously done, we identify for the very first time spurious 5 modes in MOR for time-harmonic Maxwell’s equations and 6 propose a methodology to remove their negative influence on the 7 reduced order model (ROM) response. These spurious modes 8 have nonzero resonance...
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Extending the Frequency Limit of Microstrip-Coupled CSRR Using Asymmetry
PublicationAbstract— This article explains the frequency limitation in designing microstrip circuits based on a complementary split-ring resonator (CSRR) and reports a novel technique for increasing its operating frequency, which makes the CSRR suitable for high-frequency applications. This study helps in synthesizing the dimensions of symmetric CSRR (SCSRR) and asymmetric CSRR (ACSRR) circuits, which shows the applicability of the proposed...
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Editorial for the special issue on advances in forward and inverse surrogate modeling for high-frequency design
PublicationThe design of modern‐day high‐frequency devices and circuits, including microwave/RF, antenna and photonic components, historically has relied on full‐wave electromagnetic (EM) simulation tools. Initially used for design verification, EM simulations are nowadays used in the design process itself, for example, for finding optimum values of geometry and/or material parameters of the structures of interest. In a growing number of...
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Computationally-Efficient Statistical Design and Yield Optimization of Resonator-Based Notch Filters Using Feature-Based Surrogates
PublicationModern microwave devices are designed to fulfill stringent requirements pertaining to electrical performance, which requires, among others, a meticulous tuning of their geometry parameters. When moving up in frequency, physical dimensions of passive microwave circuits become smaller, making the system performance increasingly susceptible to manufacturing tolerances. In particular, inherent inaccuracy of fabrication processes affect...
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Toward mechanosynthesis of diamondoid structures: vii. simple strategy of building atomically perfect spm tip through attachment of c60 molecule to commercial silicon tip by controlled hydrogen atom desorption from tip asperity si(111) silicon surface
PublicationZaproponowano strategię unieruchomienia cząsteczki c60 na ostrzu chandlowego czujnika spm zbudowanego z krzemu. strategia składa się z czterech prostych etapów i prowadzi do ostrza spm o atomowo zdefiniowanej budowie. modelowanie właściwości ostrza sugeruje, że mogło by ono mieć zastosowanie w mechanosyntezie.
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Bayesian Optimization for solving high-frequency passive component design problems
PublicationIn this paper, the performance of the Bayesian Optimization (BO) technique applied to various problems of microwave engineering is studied. Bayesian optimization is a novel, non-deterministic, global optimization scheme that uses machine learning to solve complex optimization problems. However, each new optimization scheme needs to be evaluated to find its best application niche, as there is no universal technique that suits all...
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Edge-Guided Mode Performance and Applications in Nonreciprocal Millimeter-Wave Gyroelectric Components
PublicationThe analogies between the behavior of gyromagnetic and gyroelectric nonreciprocal structures, the use of the simple transfer matrix approach, and the edge-guided (EG) wave property, supported in a parallel plate model for integrated magnetized semiconductor waveguide, are investigated in those frequency regions, where the effective permittivity is negative or positive. As with their ferrite counterparts, the leakage of the EG waves...
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Drilling couples and refined constitutive equations in the resultant geometrically non-linear theory of elastic shells
PublicationIt is well known that distribution of displacements through the shell thickness is non-linear, in general. We introduce a modified polar decomposition of shell deformation gradient and a vector of deviation from the linear displacement distribution. When strains are assumed to be small, this allows one to propose an explicit definition of the drilling couples which is proportional to tangential components of the deviation vector....
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Communication and Load Balancing Optimization for Finite Element Electromagnetic Simulations Using Multi-GPU Workstation
PublicationThis paper considers a method for accelerating finite-element simulations of electromagnetic problems on a workstation using graphics processing units (GPUs). The focus is on finite-element formulations using higher order elements and tetrahedral meshes that lead to sparse matrices too large to be dealt with on a typical workstation using direct methods. We discuss the problem of rapid matrix generation and assembly, as well as...
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Novel structure and size-reduction-oriented design of microstrip compact rat-race coupler
PublicationIn this paper, a novel structure of a miniaturized microstrip rat-race coupler has been proposed. Surrogate-based optimization procedures are applied to explicitly reduce the coupler size while maintaining equal power split at the operating frequency of 1 GHz and sufficient bandwidth for return loss and isolation characteristics. The optimization is performed using the objective function with four penalty components. The footprint...
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Estimation of structural stiffness with the use of Particle Swarm Optimization
PublicationThe paper presents the theoretical background and four applications examples of the new method for the estimation of support stiffness coefficients of complex structures modelled discretely (e.g. with the use of the Finite Element Model (FEM) method based on the modified Particle Swarm Optimization (PSO) algorithm. In real-life cases, exact values of the supports’ stiffness coefficients may change for various reasons...
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Frequency-Reconfigurable Hybrid SIW-Based Self-Diplexing Antenna Using Solid and Liquid Dielectric Loading
PublicationThis paper presents a novel frequencyreconfigurable self-diplexing antenna (SDA) utilizing a hybrid substrate-integrated waveguide (SIW). The antenna comprises a radiating slot, a feeding network, and a hybrid SIW cavity featuring half-mode circular and half-mode rectangular SIW structures. The unique feature of this antenna lies in its fine-tuning capability of each resonant frequency by inserting or injecting solid and liquid...
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Enhanced uniform data sampling for constrained data‐driven modeling of antenna input characteristics
PublicationData-driven surrogates are the most popular replacement models utilized in many fields of engineering and science, including design of microwave and antenna structures. The primary practical issue is a curse of dimensionality which limits the number of independent parameters that can be accounted for in the modelling process. Recently, a performance-driven modelling technique has been proposed where the constrained domain of the...
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Anion recognition by n,n'-diarylalkanediamides
PublicationThe preparation of N,N'-diarylalkanediamides from respective aliphatic dicarboxylic acidesand 4-nitroaniline via microwave-promoted reactions is presented. The most positive effect of microwave irradiation was observed for N,N'-bis(4-nitrophenyl)butanediamide. Anion binding studies on the obtained diamides were carried out in DMSO and acetonitrile using UV-vis and 1H NMR spectroscopy. A mechanism for selective fluoride recognition...
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Prediction of the fatigue lifetime of PUR structural elements using a combined experimental-numerical approach
PublicationThis paper presents a method for estimating the fatigue life of polyurethane elastomeric components. A rubber replacement - polyurethane of hardness 80ShA commonly used in vibration damping systems, for example, in motor vehicle suspensions, was used for the study. A metal-rubber bushing component was selected for analysis, and numerical analysis was carried out along with a fatigue model proposal based on a modification of the...
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Direct measurements, numerical predictions and simple formula estimations of welding-induced biaxial residual stresses in a full-scale steel stiffened plate structure
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Impact response of novel layered two stage fibrous composite slabs with different support type
PublicationThe performance of novel Layered Two Stage Fibrous Composite slabs (LTSFC) was pioneered under falling mass collisions using a combined experimental and numerical study. Such LTSFC slabs consist of three layers with and without the insertion of glass fibre mesh between the layers. LTSFC techniques were used to fabricate the composite slabs with three layers including 3%, 1.5%, and 3% of fibre content for the top, middle, and...
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Impact performance of novel multi-layered prepacked aggregate fibrous composites under compression and bending
PublicationMulti-layered Prepacked aggregate fibrous composite (MLPAFC) is a new type of concrete, which is prepared in two subsequent stages of aggregate-fibre skeleton prepacking and cementitious grouting. In this study, ten MLPAFC mixtures were prepared in three subsequent layers incorporating different contents of four different types of steel fibres. Long and short hooked-end and crimped steel fibers were adopted with 3.0 and 1.5% dosages...
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Low-cost multiband compact branch-line coupler design using response features and automated EM model fidelity adjustment
PublicationDesign closure of compact microwave components is a challenging problem because of significant electromagnetic (EM) cross-couplings in densely arranged layouts. A separate issue is a large number of designable parameters resulting from replacement of conventional transmission line sections by compact microstrip resonant cells. This increases complexity of the design optimization problem and requires employment of expensive high-fidelity...
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Optimization of the Hardware Layer for IoT Systems using a Trust Region Method with Adaptive Forward Finite Differences
PublicationTrust-region (TR) algorithms represent a popular class of local optimization methods. Owing to straightforward setup and low computational cost, TR routines based on linear models determined using forward finite differences (FD) are often utilized for performance tuning of microwave and antenna components incorporated within the Internet of Things systems. Despite usefulness for design of complex structures, performance of TR methods...
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Application of passive sampling techniques as a usable tool in the field of environmental quality monitoring
PublicationAnalysis of literature data published for the past 20 years leads to the conclusion, that passive sampling technique has been developing very quickly and is commonly used in the field of monitoring pollutants in air, water and soil environment. The popularity of application of passive sampling techniques in analytical and environmental chemistry results from its many advantages e.g.: Simplicity in use, low costs of exploitation,...
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Kinetics and mechanism of the chemically modified starches during gelatinization.
PublicationNative starch was silicated by means of microwave-assisted reactions with varying doses of reagents. Resulting products were characterized by DSC and HMR-relaxation methods. It was observed that the hydratation of the silicated starches during gelatinization decreases when compared to that of the native potato starch. The amount of unfrozen water for ungelitinizated silicated starches are less than in control samples. At the same...
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Local Mesh Deformation for accelerated parametric studies based on the Finite Element Method
PublicationThis paper presents an approach for enhancing the efficiency of two-dimensional Finite Element Method analysis in parametric studies or optimisation process of microwave components. The new approach involves local mesh deformation applied near the elements that are modified during computations. Since in the proposed approach the topology of the mesh remains unchanged, a new mesh does not have to be generated from scratch when the...
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Nanocrystalline diamond sheets as protective coatings for fiber-optic measurement head
PublicationFiber-optic sensors find numerous applications in science and industry, but their full potential is limited because of the risk of damaging the measurement head, in particular, due to the vulnerability of unprotected tips of the fiber to mechanical damage and aggressive chemical agents. In this paper, we report the first use of a new nanocrystalline diamond structure in a fiber-optic measurement head as a protective coating of...
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Low-Cost Quasi-Global Optimization of Expensive Electromagnetic Simulation Models by Inverse Surrogates and Response Features
PublicationConceptual design of contemporary high-frequency structures is typically followed by a careful tuning of their parameters, predominantly the geometry ones. The process aims at improving the relevant performance figures, and may be quite expensive. The reason is that conventional design methods, e.g., based on analytical or equivalent network models, often only yield rough initial designs. This is especially the case for miniaturized...
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Remote Monitoring System for Impedance Spectroscopy using Wireless Sensor Network
PublicationThe architecture of a miniaturized impedanceanalyser with wireless communication module for remoteImpedance Spectroscopy (IS) of anticorrosion coatings ondifficult-to-reach objects (e.g. on the steel construction ofthe bridge) is described in this paper. Some practical aspectsof implementation of a Wireless Sensor Network (WSN) arealso discussed. A low scale, middle range, WSN networkcomposed of a Base Station (BS) with a Personal...
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Monitoring of volatile organic compounds (VOCs) in atmospheric air. Part II. Sample collection and preparation
PublicationThe paper reviews literature information on air sampling techniques commonly used for monitoring volatile organic compounds (VOCs) levels in atmospheric air. It describes containers for collecting samples of atmospheric air, such as vacuum canisters and bags made from synthetic materials. It discusses dynamic, passive and denudational techniques for sampling analytes from air combining isolation with preliminary enrichment, and...
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Design optimization of novel compact circular polarization antenna
PublicationThe paper describes a structure and a design optimization procedure of a miniaturized circular polarization antenna with elliptical ground plane slots and feed line with stepped-impedance stubs. Constrained optimization of all antenna parameters is executed in order to explicitly reduce the antenna size while maintaining required impedance axial ratio bandwidth of 5 GHz to 7 GHz at the same time. The size of the optimized antenna...
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Automated Design of Linear Phase Filters
PublicationThis paper presents a fast technique for an automated design of microwave filters with linear phase. The proposed method exploits the cost function defined using the location of complex zeros and poles of the filter’s transfer and reflection function. The effectiveness of the proposed technique is presented with two illustrative examples.
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Investigation of H2:CH4 plasma composition by means of spatially resolved optical spectroscopy
PublicationThe system based on spatially resolved optical emission spectroscopy dedicated for in situ diagnostics of plasma assisted CVD processes is presented in this paper. Measurement system coupled with chemical vapour deposition chamber by dedicated fiber-optic paths enables investigation of spatial distribution of species densities (Hx, H+, CH, CH+) during chemical vapour deposition process. Experiments were performed for a various...
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The crystal structures of (<i>O</i>-silyl)thiobenzoates (<sup><i>t</i></sup>BuO)<sub>3</sub>SiOC(S)Ph, Ph<sub>3</sub>SiOC(S)Ph, (2,6-XyO)<sub>3</sub>SiOC(S)Ph, and PhC(O)SSSC(O)Ph
PublicationChlorek benzylu reaguje z silanotiolanami sodu R3SiSNa dając wyłącznie pochodne sililowe kwasu monotiobenzoesowego R3SiOC(S)Ph, R=t-Bu, Ph lub 2,6-XyO w postaci pomarańczowych kryształów. Wymienione produkty zostały poddane rentgenowskiej analizie strukturalnej. Badania NMR roztworów tych substancji wskazują, że te same izomery są obecne w roztworze i w ciele stałym.
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Reactions of R2P-P(SiMe3)2 with [(R'3P)2PtCl2]. Syntheses and Structures of [μ2-(1,2:2-η-P2){Pt(PEt3)2}2{Pt(PEt3)2Cl}]+Cl-, [{(Et2PhP)2Pt}2P2], [{(p-Tol3P)2Pt}2P2] and [(p-Tol3P)ClPt(μ-PPh2)2Pt(p-Tol3P)Cl]
PublicationReakcje difosfanów R2P-P(SiMe3)2 z [(R'3P)2PtCl2] są bardzo złożone. Główną ścieżką reakcji jest rozszczepienie wiązania P-P w startowym R2P-P(SiMe3)2, po czym następuje utworzenie kompleksu zawierającego P2: [{(R'3P)2Pt}2P2] oraz difosfanu R2P-PR2. Produkty reakcji (zarówno główne jak i uboczne), zostały scharakteryzowane na podstawie spektroskopii 31P NMR. Dla czterech tytułowych związków wykonano rentgenowską analizę strukturalną...
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Miniaturization of ESPAR Antenna Using Low-Cost 3D Printing Process
PublicationIn this paper, the miniaturized electronically steerable parasitic array radiator (ESPAR) antenna is presented. The size reduction was obtained by embedding its active and passive elements in polylactic acid (PLA) plastic material commonly used in low-cost 3D printing. The influence of 3D printing process imperfections on the ESPAR antenna design is investigated and a simple yet effective method to compensate them has been proposed....
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A GPU Solver for Sparse Generalized Eigenvalue Problems with Symmetric Complex-Valued Matrices Obtained Using Higher-Order FEM
PublicationThe paper discusses a fast implementation of the stabilized locally optimal block preconditioned conjugate gradient (sLOBPCG) method, using a hierarchical multilevel preconditioner to solve nonHermitian sparse generalized eigenvalue problems with large symmetric complex-valued matrices obtained using the higher-order finite-element method (FEM), applied to the analysis of a microwave resonator. The resonant frequencies of the low-order...
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Haemocompatibility Of Non-Functionalized And Plasmachemical Functionalized Detonation Nanodiamond Particles
PublicationThe purpose of this paper is to present the innovative design of microwave plasma system for modification of detonation nanodiamond particles (DNP) using a special rotating drum placed inside the reactor. Nanodiamond particles manufactured by detonation method reveal the biological activity depending on surface functionalization. Plasmachemical modification of detonation nanodiamond particles gives the possibility of controlling...
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Identification of the Vistula Mounting tower model using measured modal data
PublicationW pracy przedstawiono problem identyfikacji pięcioparametrowego modelu zabytkowej wieży twierdzy Wisłoujście. Poszukiwane parametry wyznaczono jako rozwiązanie problemu minimalizacji błędu średniokwadratowego pomierzonych dwóch pierwszych częstości i pierwszej postaci drgań własnych. Do tego celu wykorzystano hierarchiczną procedurę minimalizacji przy zastosowaniu analizy wrażliwości. Analiza numeryczna potwierdziła efektywność...
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Historic bridge modelling using laser scanning, ground penetrating radar and finite element methods in the context of structural dynamics
PublicationPraca dotyczy modelowania MES zabytkowej konstrukcji mostowej przy użyciu danych geometrycznych pochodzących ze skanowania laserowego oraz georadaru. Z uwagi na brak badań materiału budujcego most, przeprowadza się analize wrażliwości konstrukcji na zmiany modułu sprężystości granitu.
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Non-linear FEM analysis of earthquake-induced pounding between the main building and the stairway tower of the Olive View Hospital
PublicationCelem artykułu jest dokładna, trójwymiarowa analiza MES dotycząca zderzeń pomiędzy budynkiem głównym a konstrukcją wolnostojącej klatki schodowej szpitala Olive View podczas trzęsienia ziemi San Fernando w roku 1971. Wyniki analizy pokazują, iż kolizje mogą prowadzić do znacznego wzrostu odpowiedzi lżejszej konstrukcji klatki schodowej, powodować uszkodzenia w miejscach kontaktu oraz potęgować uszkodzenia u podstawy tej budowli....
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Earthquake-induced pounding between equal height buildings with substantially different dynamic properties
PublicationZderzenia pomiędzy konstrukcjami budowlanymi podczas trzęsień ziemi mogą prowadzić do znacznych uszkodzeń czy nawet całkowitego zniszczenia. Celem niniejszego artykuły jest analiza zderzeń pomiędzy budynkami o jednakowej wysokości i różnych parametrach dynamicznych. W artykule przedstawiono wyniki badań numerycznych przeprowadzonych na nieliniowych modelach dyskretnych o skupionych masach z wykorzystaniem nieliniowego modelu lepkosprężystego...
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Influence of statistical errors on damage detection based on structuralflexibility and mode shape curvature
PublicationDamage detection procedures based on measured natural frequencies and building structure mode shapes are discussed in this paper. Modal curvature and structural flexibility approaches are tested. Attention is paid to the modal identification errors that influence damage detection. This problem is studied using a computer simulation of a simple supported beam. For practical cases, the peak picking methodand its statistical errors...
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Pounding force response spectrum under earthquake excitation
PublicationW artykule przedstawiono możliwość wykorzystania spektrum siły zderzenia jako zaproponowanego przez autora narzędzia pomocnego przy projektowaniu budynków narażonych na zderzenia podczas trzęsień ziemi. Przedstawione wykresy spektrów pokazały, iż właściwy dobór parametrów budowli, takich jak szerokość przerwy pomiędzy budynkami, okres drgań własnych konstrukcji, liczba tłumienia, masa, współczynnik ciągliwości, czy też przesunięcie...
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The effect of waste-expanded perlite on alkali activation of ground granulated blast furnace slag
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Study of a plate modelling a dock gate
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Degenerated isoparametric finite elements in nonlinear analysis of 2D-problems
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Is reduced integration just a numerical trick
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