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Wyniki wyszukiwania dla: WIND TURBINE, OFFSHORE, FEA, MODAL ANALYSIS, DYNAMIC COUPLING, SENSITIVITY ANALYSIS, DESIGN OF EXPERIMENT, RESPONSE SURFACE METHOD.
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Analysis of the possibility of increasing thermal-electric energy conversion ratio in CHP units based on micro gas turbine
PublikacjaThe aim of this paper is to analyze the possibility of increasing thermal energy to electricity conversion efficiency in combined heat and power (CHP) units based on micro gas turbine during low heat demand periods. At the beginning sustainable development postulates under power engineering are explained. Next micro CHP as part of distributed generation idea is presented. The main part of the article is based on results of thermodynamic...
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Actual field corrosion rate of offshore structures in the Baltic Sea along depth profile from water surface to sea bed
PublikacjaThe paper presents the results of field electrochemical investigations on the corrosion rate of carbon steel in seawater of the Baltic Sea at the location of the Baltic Beta production rig. The measurements were conducted throughout the year in seawater at different depths from the sea surface to the sea bed (about 75 m). The results revealed corrosion aggressiveness of the seawater along the entire depth profile. There was...
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Finite element modeling of plastic hinges based on ductility demand-capacity method using nonlinear material for dynamic analysis
PublikacjaThe article discusses modeling plastic hinges in reinforced concrete interme-diate supports using finite elements methods. The ductility demand-capacitymethod was used to determine the geometrical parameters of cross-section plas-ticization zones, their ability to move and rotate, as well as their ductility. Dueto the varied geometry and stiffness of the supports and their nonlinear behav-ior under dynamic load, this method was...
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Analysis of ship shaft line coupling bolts failure
PublikacjaW artykule przedstawiono dane statystyczne dotyczące uszkodzeń linii wałów okrętowych, w tym także pęknięć zmęczeniowych śrub sprzęgieł kołnierzowych wałów. Wyjaśniono także mechanizm powstawania tego typu uszkodzeń i zagrożenia jakie niosą ze sobą. Opisano przypadki takich uszkodzeń oraz badania jakie są prowadzone dla lepszego poznania zjawisk zmęczeniowych w omawianych uszkodzeniach.
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Mechanical response of 6061-T6 aluminium alloy subjected to dynamic testing at low temperature: Experiment and modelling
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SDGs implementation, their synergies, and trade-offs in EU countries – Sensitivity analysis-based approach
PublikacjaSustainable development is one of the most urgent challenges facing humanity. Its basic principle is to improve people’s well-being and maintain it over time. In 2015, the United Nations approved 17 sustainable development goals (SDGs) to ensure a better and sustainable future for all, balancing economic, social and environmental development. SDGs create an ‘indivisible whole’; thus, examining their interactions is crucial. Our...
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RANS-based design optimization of dual-rotor wind turbines
PublikacjaPurpose An improvement in the energy efficiency of wind turbines can be achieved using dual rotors. Because of complex flow physics, the design of dual-rotor wind turbines (DRWTs) requires repetitive evaluations of computationally expensive partial differential equation (PDE) simulation models. Approaches for solving design optimization of DRWTs constrained by PDE simulations are investigated. The purpose of this study is to determine...
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Numerical analysis of a temporary steel grandstand
PublikacjaThe purpose of this paper is to present the results of the numerical analysis focused on the response of the temporary steel scaffolding grandstand subjected to human-induced vibrations due to jumping. Shell as well as beam elements have been used in the numerical model. Its first stage has involved conducting modal analysis in order to determine the modes of free vibrations and the corresponding natural frequencies for the empty...
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DESIGN AND THEORETICAL ANALYSIS OF A PROTOTYPE TILTING-PAD RADIAL BEARING WITH ADJUSTABLE CLEARANCE
PublikacjaThe article introduces a design and analysis results of a prototype ORC (organic Rankine cycle) turbo generator rotor assembly of 300kW power, supported by tilting-pad bearings of original design. The calculations were performed for a prototype turbo generator rotor. The shaft of this machine is supported with two radial bearings, lubricated with an unusual lubricant – a low-boiling-point agent. The main objective of the presented...
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Fast multi-criterial statistical analysis and design optimization of compact microwave couplers
Publikacja—A rapid statistical analysis and yield estimation of compact microwave couplers involving multiple performance parameters has been presented. The analysis is realized using a fast surrogate model representing appropriate characteristic points of the coupler response. Because of less nonlinear dependence of the characteristic points on the structure geometry (compared to the original response, i.e., S-parameters vs. frequency),...
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Analysis of Validation and Simplification of Timber-Frame Structure Design Stage with PU-Foam Insulation
PublikacjaThe transition from experimental studies to the realm of numerical simulations is often necessary for further studies, but very difficult at the same time. This is especially the case for extended seismic analysis and earthquake-resistant design. This paper describes an approach to moving from the experimental testing of an elementary part of a wood-frame building structure to a numerical model, with the use of a commercial engineering...
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Polynomial analysis as a new way of describing dynamic impedance spectra – Differential and relative impedance spectra
PublikacjaModel measurements of an equivalent electrical system were carried out using the technique of Dynamic Electrochemical Impedance Spectroscopy. The measurement took the form of potentiodynamic changes imposed on the tested system. Using the possibility of continuous impedance measurements, an attempt was made to develop an original and innovative method of analyzing impedance spectrograms, which is termed polynomial analysis. As...
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VSC converters control for offshore wind farms HVDC grid connection
PublikacjaThe paper proposes a voltage sourced converter (VSC) new control method. A well-known in the electric power systems correlation between voltage angle and active power and correlation between voltage and reactive power is used instead of feedforward control. This allows for a fast and almost independent control of active and reactive power flow.
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Rigorous Modal Analysis of Structures Containing Inhomogeneous Dielectric Cylinders.
PublikacjaW pracy wykorzystano zmodyfikowaną procedurę iteracyjną i metodę dopasowania rodzajów w celu analizy struktur zawierających asymetrycznie umieszczone, niepełnej wysokości lub wielowarstwowe, niejednorodne, cylindryczne rezonatory dielektryczne. Analiza bazuje na nowatorskiej koncepcji zwanej hybrydową macierzą impedancyjną (HIM - hybryd impedancje matrix), która opisuje relacje pomiędzy całkowitym polem elektrycznym i magnetycznym...
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Failure of cylindrical steel silos composed of corrugated sheets and columns and repair methods using a sensitivity analysis
PublikacjaW artykule omówiono przypadek awarii metalowego silosu z blachy walcowej i pionowych słupów. Wykonano analizę wyboczeniową MES z uwzględnieniem imperfekcji geometrycznych. Omówiono metody naprawcze i ich optymalizację w oparciu o analizę wrażliwości.
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Analysis of the effect of the seismic gap on the response of buildings experiencing pounding during earthquakes
PublikacjaThe aim of this paper is to investigate the effect of the seismic gap on the dynamic response of buildings experiencing earthquake-induced pounding. Three buildings have been analysed, which are 5-storey, 7-storey and 9-storey structures. Three possible pounding scenarios have been considered, which are pounding between 5-storey and 7-storey buildings, pounding between 5-storey and 9-storey buildings and pounding between 7-storey...
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A conceptual design and numerical analysis of the mixerless urea-SCR system
PublikacjaIn the present study, an innovative design of the urea-selective catalytic reduction (SCR) system without conventional mixing elements was developed. The aim was to obtain a high degree of urea decomposition, and uniform ammonia distribution at the inlet to the catalyst, while minimising the liquid film deposition and keeping the compact design. The concept of the design was based on creating high turbulences and elongating...
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A comparative analysis of numerically simulated and experimentally measured static responses of a floating dock
PublikacjaTwo numerical methods, dynamic and static analyses, are proposed to calculate the static responses of a floating dock under different ballast water distributions. Model-scale experimental tests were conducted to compare with these numerical methods. The dynamic analysis includes a 6-degree-of-freedom (6-DOF) model, a hydrostatic force model and a hydrodynamic force model to simulate the dock's freely floating processes. The dock's...
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Multiobjective Aerodynamic Optimization by Variable-Fidelity Models and Response Surface Surrogates
PublikacjaA computationally efficient procedure for multiobjective design optimization with variable-fidelity models and response surface surrogates is presented. The proposed approach uses the multiobjective evolutionary algorithm that works with a fast surrogate model, obtained with kriging interpolation of the low-fidelity model data enhanced by space-mapping correction exploiting a few high-fidelity training points. The initial Pareto...
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DYNAMIC ANALYSIS OF THE RAILWAY BRIDGES IN POLAND WITH REGARDS TO HIGH-SPEED TRAINS PASSAGE ADJUSTMENT
PublikacjaThe dynamic analysis of the railway bridge in Tczew was carried out in the article as an example of such bridges adaptation suitability to handle high-speed trains. Calculations of railway bridges are greatly complicated and labor-consuming. The bridge model and a rolling stock passage simulation were developed in the SOFISTIK software. Three types of elements were used for the correct mapping of the structure in the calculation...
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Dynamic analysis of temporary steel grandstand subjected to human-induced excitations due to jumping
PublikacjaSteel grandstands are structures that are frequently used during sport games and many other non-sporting events, such as festivals, music concerts, or even politicians rallies, with participation of a large number of attendees. Unfortunately, the presence of unexpected excessive dynamic loads due to unpredictable behaviour of spectators (e.g. synchronized harmonic jumping or swaying) may lead to...
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Determination of the optimal curvature of the turnout diverging track for HSR using dynamic analysis
PublikacjaThe paper presents an analytical method of identifying the curvature of the turnout diverging track consisting of sections of varying curvature. Such turnout is mainly applied on High Speed Railway. Both linear and nonlinear (polynomial) curvatures of the turnout diverging track are considered in the paper. Obtained solutions enable to assume curvature values at the beginning and end point of the geometrical layout of the turnout.The...
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Response features for fast EM-driven design of miniaturized impedance matching transformers
PublikacjaA framework for low-cost EM-driven design optimization of compact impedance matching transformers is presented. Our technique is based on a bottom-up design where design requirements for the transformer circuit are translated into specifications for its building blocks. These elementary cells are optimized using response features. Subsequently, the entire circuit is fine-tuned using local response surface approximation models and...
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Coupled DEM/CFD analysis of impact of free water on the static and dynamic response of concrete in tension regime
PublikacjaW tym artykule zbadano numerycznie quasi-statyczne i dynamiczne zachowanie częściowo nasyconego płynem betonu w warunkach dwuwymiarowego (2D) jednoosiowego rozciągania w mezoskali. Obliczono, jaki wpływ ma zawartość wolnego płynu porowego (gazu i wody) na proces pękania i wytrzymałość betonu w rozciąganiu. Do symulacji zachowania betonu całkowicie i częściowo nasyconego płynem w warunkach quasi-statycznych i dynamicznych wykorzystano...
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Sensitivity analysis of thin-walled members, problems and applications
PublikacjaPodano przegląd problemów analizy wrażliwości konstrukcji cienkościennych. Przedstawiono metody określania pierwszej wariacji zmiennych stanu takich jak: przemieszczenia, siły wewnętrzne, reakcje, częstości i postaci drgań własnych oraz obciążeń krytycznych ze względu na zmiany parametrów konstrukcji. Rozważania ograniczono do prętów cienkościennych o otwartym bisymetrycznym przekroju poprzecznym w ramach założeń teorii prętów...
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An analysis of wind conditions at pedestrian level in the selected types of multi-family housing developments
PublikacjaThe following article addresses the issue of wind conditions around urban building development at pedestrian level. Factors that depend on those issues include wind comfort and air quality within urbanized spaces. The conditions specific of cities located in a temperate climate zone have been taken into account. The article is intended to identify aerodynamic phenomena characteristic of the three basic types of multi-family building...
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Computational Fluid Dynamic study on the wind characteristics of a multifunctional building system model in developed coastal cities
PublikacjaThis paper presents an approach for providing innovative technology by applying fluid mechanics to the field of architectural design. The aim is to make a building’s shape profitable and strengthen environmental protection by using the wind force to create an integrated wind absorption definition for a multifunctional building system model. Furthermore, taking control of the wind flow over an object can have an impact on not only...
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Analysis of pavement structure sensitivity to passage of oversized heavy duty vehicle in terms of bearing capacity
PublikacjaOversized heavy duty vehicles occur in traffic very rarely but they reach extremely high weights, even up to 800 tonne. The detrimental impact of these vehicles on pavement structure is much higher than in case of commercial vehicles that comprise typical traffic, thus it is necessary to assess the sensitivity of pavement structure to passage of oversized vehicles. The paper presents results of sample calculations of load equivalency factor...
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Timber frame houses resistant to dynamic loads - seismic analysis
PublikacjaThe aim of the article is to present results of seismic analysis results of two real-sized timber frame buildings subjected to seismic excitations. The first model was insulated with mineral wool, the second one with polyurethane foam. Technology and specifications involved in both models construction is based on the previously conducted experimental research on timber frame houses, including wall panels tests, wall numerical models...
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Active Kriging-based conjugate first-order reliability method for highly efficient structural reliability analysis using resample strategy
PublikacjaEfficient structural reliability analysis method is crucial to solving reliability analysis of complex structural problems. High-computational cost and low-failure probability problems greatly limit the efficiency in structural reliability analysis problems, causing the safety and reliability of the structure to be questioned. In this work, a highly efficient structural reliability analysis method coupling active Kriging algorithm...
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Electrocatalytic gas sensor response analysis
PublikacjaW pracy przedstawiono i porównano metody analizy odpowiedzi elektrokatalitycznych czujników gazów toksycznych. Opisane metody pozwalają na ekstrakcje z odpowiediz czujników informacji o rodzaju gazu oraz o jego stężeniu.
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Behavior Analysis and Dynamic Crowd Management in Video Surveillance System
PublikacjaA concept and practical implementation of a crowd management system which acquires input data by the set of monitoring cameras is presented. Two leading threads are considered. First concerns the crowd behavior analysis. Second thread focuses on detection of a hold-ups in the doorway. The optical flow combined with soft computing methods (neural network) is employed to evaluate the type of crowd behavior, and fuzzy logic aids detection...
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Pedestrian on footbridges, vertical loads and response
PublikacjaThe paper is a synthesis of the experimental and theoretical investigations on dynamics of pedestrian bridges under vertical load The subject is divided into four issues.1) The pedestrian as a vertical dynamic load on footbridges, theoretic load function for walking and crouching.2) Crowd walking on the footbridge - pedestrian flow.3) Vertical lock-in effect.4) Response of the footbridge - numeric and side test results, -...
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Variable-fidelity response feature surrogates for accelerated statistical analysis and yield estimation of compact microwave components
PublikacjaAccounting for manufacturing tolerances is an essential part of a reliable microwave design process. Yet, quantification of geometry and/or material parameter uncertainties is challenging at the level of full-wave electromagnetic (EM) simulation models. This is due to inherently high cost of EM analysis and massive simulations necessary to conduct the statistical analysis. Here, a low-cost and accurate yield estimation procedure...
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Analysis of Accuracy of Modified Gradient Method in Indoor Radiolocalisation System
PublikacjaIn this paper a new method, called modified gradient method, has been proposed for position calculation on the basis of distance measurement in indoor environment. It is shown that well known method of position calculation such as Foy is inefficient in indoor environment. In this article is also described the indoor radiolocalisation system which was used for collecting distance measurements which were employed for further comparative...
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The point estimate method in a reticulated shell reliability analysis
PublikacjaThe objective of this paper is to present an application of the point estimate method (PEM) that can determine the probabilistic moments for engineering structures. The method is reasonably robust and adequately accurate for a wide range of practical problems. It is a special case of numerical quadrature based on orthogonal polynomials. The main advantage of this method is that, unlike FORM or SORM, it is not necessary to carry...
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Analysis of the design development of the sliding table saw spindles
PublikacjaProducers of sliding table saws constantly strive for improvement in sawing accuracy. One of the method is an upswing in a spindle behavior, since, it affects to a large degree sawing effects. The design development of sliding table saw spindles during the last quarter-century is presented. The spindle system of the modernized spindle of the sawing machine Fx550 is described.
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PARAMETRIC ANALYSIS OF THE EFFICIENCY OF THE COMBINED GAS-STEAM TURBINE UNIT OF A HYBRID CYCLE FOR THE FPSO VESSEL
PublikacjaA thermal diagram of the combined gas‒steam turbine unit of a hybrid cycle, which is an energy complex consisting of a base gas turbine engine with a steam turbine heat recovery circuit and a steam-injected gas turbine operating with overexpansion, is proposed. A mathematical model of a power plant has been developed, taking into consideration the features of thermodynamic processes of simple, binary, and steam-injected...
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Frontier education for a sustainable future - speculative design in architecture as a transdisciplinary experiment
PublikacjaIn this article, the authors propose the term frontier education referring to the well-established notion of frontier research - one, that through opening unexpected transdisciplinary perspectives, may offer new insights and create a fertile ground for new discoveries and ground-breaking concepts. In answer to the question of how to get rid of normative thinking and extend architectural experimentations, a speculative design architectural...
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Quasi-Static Response
PublikacjaConcern for the quasi-static response of ship and offshore structures, as required for safety and serviceability assessments. Attention shall be given to uncertainty quantification of quasi-static load and response analysis approaches, and their limitations, including exact and approximate methods for derivation of different acceptance criteria.
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DYNAMIC ANALYSIS OF HISTORIC RAILWAY BRIDGES IN POLAND IN THE CONTEXT OF ADJUSTING THEM TO PENDOLINO TRAINS
PublikacjaThe article presents the dynamic analysis of the historic railway bridge in Tczew as an example of the usefulness of such type of bridge for high-speed trains. The model of the bridge and the simulation of rolling stock passage was performed in SOFISTIK program. The scope of work includes experimental studies, the solution of the problem concerning the correct solution features dynamic model takes into account the dependencies...
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An energetic analysis of a gas turbine with regenerative heating using turbine extraction at intermediate pressure - Brayton cycle advanced according to Szewalski's idea
PublikacjaIn this paper, a modification of a simple gas turbine into the Brayton cycle with regenerative heating, using turbine extraction at intermediate pressure, is presented. The main concept of the retrofitting is based on the transfer of heat from the turbine exhaust gases to the air entering the combustion chamber. The extracted gas transfers heat to air via the divided regenerative heat exchanger and after that is compressed and...
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Technical and economical analysis of combined cycles of gas turbine -steam turbine on pipeline compressor stations. Part II - Economic analysis
PublikacjaW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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Technical and economical analysis of combined cycles of gas turbine - steam turbine on pipeline compressor stations. Part I - Technical analysis
PublikacjaW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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Technical and economical analysis of combined cycles of gas turbine - steam turbine on pipeline compressor stations. Part II - Economic analysis
PublikacjaW pracy przedstawiono zagadnienie nadbudowy zespołów turbosprężarkowych, znajdujących się na tłoczni gazu ziemnego, odzyskowymi blokami parowymi. W analizie tego przedsięwzięcia wzięto pod uwagę kilka wariantów konfiguracji układu parowego oraz kilka wariantów uwzględniających zmienność obciążenia turbin gazowych napędzających kompresory. Dla układu parowego dobrano wszystkie podstawowe parametry, a następnie wykonano obliczenia...
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Design advantages and analysis of a novel five-phase doubly-fed induction generator
PublikacjaPurpose – The purpose of this paper is to provide an analysis of the performance of a new five-phase doubly fed induction generator (DFIG). Design/methodology/approach – This paper presents the results of a research work related to fivephase DFIG framing, including the development of an analytical model, FEM analysis as well as the results of laboratory tests of the prototype. The proposed behavioral level analytical model is based...
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Variable Size Twin-Rotor Wind Turbine
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CFGFRPT Piles with a Circular Cross-Section and their Application in Offshore Structures
PublikacjaThe possibilities of using concrete piles in a polymer composite reinforced with glass fibres in offshore facilities were shown. Laboratory tests of CFGFRPT type piles compressed axially and in eccentric compression for the analysis of CFGFRPT piles were used. Methods of analysis of dynamic systems for mathematical modelling of the displacement of the hammer in the pile driving process were applied. The possibilities of combining...
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Optimization of the spindle speed during milling of large-sized structures with the use of technique of Experiment-Aided Virtual Prototyping
PublikacjaIn the paper are presented considerations concerning vibration suppression problems during milling of large-sized workpieces with the use of innovative method of matching the spindle speed of cutting tool. It depends on repeatable change of the spindle speed value as soon as the optimal vibration state of the workpiece approaches. The values of dominant “peaks” in the frequency spectra and the Root Mean Square (RMS) values of time...
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Design centering of compact microwave components using response features and trust regions
PublikacjaFabrication tolerances, as well as uncertainties of other kinds, e.g., concerning material parameters or operating conditions, are detrimental to the performance of microwave circuits. Mitigating their impact requires accounting for possible parameter deviations already at the design stage. This involves optimization of appropriately defined statistical figures of merit such as yield. Alt-hough important, robust (or tolerance-aware)...