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Wyniki wyszukiwania dla: vibration and buckling
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Longitudinal wave propagation. Part II, Analysis of crack influence
PublikacjaW pracy analizowano wpływ pęknięć zmęczeniowych na propagacje fali wzdłużnej w prętach. Opracowano nowe typy element ów spektralnych oparte na teorii elementarnej, Love'a, Mindlina i trójpostaciowej.
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Longitudinal wave propagation. Part I - Comparison of rod theories
PublikacjaW pracy przedstawiono modele spektralnych elementów skończonych do analizy propagacji fali wzdłuznej w pretach. Opracowano modele wykorzystujace teorię elementarną, teorie Love'a, teorie Mindlina oraz teorię trójpostaciową.
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Novel digitally controlled drive for the vibratory conveyors
PublikacjaThe presented vibratory conveyors is used in the industry for continuous transportation of loose substances over short distances (2-10 m). The conveyor is applied for transportation in aseptic conditions. To obtain high efficiency for granulatedmass with different size of grain and different physical properties it is necessary to set the appropriate vibration amplitudeindependently of vibration frequency. This is not possible with...
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Numerical Analysis of Mice Carotid Arteries’ Response Emphasizing the Importance of Material Law Constants’ Validation
PublikacjaIn this paper, a detailed validation of the passive material properties of mice carotid arteries and constants of the Fung and Holzapfel hyperelastic material laws is conducted by means of static nonlinear FEM analyses. The response of the carotid arteries in an inflation test is studied here for the following mouse models: wild-type, mdx, sgcd−/−, Eln+/+, Eln+/−, Fbln5+/+, and Fbln5−/−. All FEM computations are conducted on models...
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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) to determine the probabilistic moments for engineering structures. Reliability analysis is illustrated by two examples: an estimation of the critical force in linear elastic buckling analysis and a reticulated shell limit load determinations. Calculations were also made using Monte Carlo method. It has been shown the practical usefulness...
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Point cloud based surface analysis of prestressed concrete element in exceeded state of serviceability
PublikacjaBy definition, serviceability state is characterized by the fact that despite meeting the requirements associated with carrying capacity, the object is not suitable for use. Serviceability limit state refers to factors, such as durability, overall stability, fire resistance, cracking, excessive vibration. Perfect examples of exceeded serviceability state are the improper vibration of a skyscraper, which inhabitants may suffer from...
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Dynamics analysis of footbridge mode shapes the s8 expressway on the basis of the results of in situ tests
PublikacjaNon-destructive diagnostics for structure may use dynamic measurements realized during vibrations of a facility induced by dynamic environmental impact, enforced by the use of inductors or impulse impact. Dynamic tests and the analysis were undertaken for a footbridge situated over the expressway S8. The studies in situ allowed for dynamic characteristics to be determined: frequency, shape modes and damping for respective frequency...
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Stability analysis of single-walled carbon nanotubes embedded in winkler foundation placed in a thermal environment considering the surface effect using a new refined beam theory
PublikacjaThis article is devoted to investigate the stability of different types of Single Walled Carbon Nanotubes (SWCNTs) such as zigzag, chiral, and armchair types which are rested in Winkler elastic foundations exposing to both the low and high temperature environments. Also, the Surface effects which include surface energy and surface residual stresses, are taken into consideration in this study. It may be noted that the surface energy...
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Idea zastosowania sztucznej inteligencji w prognozowaniu wpływu drgań komunikacyjnych na odpowiedź dynamiczną budynków mieszkalnych
PublikacjaW poniższym artykule autorzy analizują wpływ drgań komunikacyjnych na budynki mieszkalne oraz metodykę pomiarową według PN-85 B-02170 [1]. Problemem badawczym jest opracowanie prostej metody prognozowania wpływu drgań na budynki mieszkalne w taki sposób, aby nie było konieczne przeprowadzanie pracochłonnych i kosztownych pomiarów polowych. W tym celu wykonano analizę przy użyciu algorytmów opartych na sztucznej inteligencji oraz...
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RAPORT - EKSPERTYZA Z POMIARÓW DRGAŃ LINII WAŁÓW NA JEDNOSTCE ORP „DĄBIE”
PublikacjaEkspertyza diagnostyczna dotycząca stanu technicznego dwóch linii transmisji mocy (linii wałów) opracowana na podstawie przeprowadzonych pomiarów drgań w 26 punktach pomiarowych, przy jednoczesnej pracy silników napędowych L i PB (wspólnej pracy linii wałów obu burt), w II zakresach ustalonego obciążenia „pół-naprzód” i „cała-naprzód”. Pomiary prędkości i przyspieszeń drgań generowanych przez węzły konstrukcyjne okrętowego układu...
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A technique of experiment aided virtual prototyping to obtain the best spindle speed during face milling of large-size structures
PublikacjaThe paper presents an original method concerning vibration suppression problem during milling of large-size and geometrically complicated workpieces with the use of novel way of selecting the spindle speed. This consists in repetitive simulations of the cutting process for subsequent values of the spindle speed, until the best vibration state of the workpiece is reached. An appropriate method of obtaining a computational model,...
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Wave Method for Structural Health Monitoring: Testing Using Full-Scale Shake Table Experiment Data
PublikacjaAn algorithm of the wave method for structural health monitoring (SHM) is tested and calibrated using shake table experiment data of a full-scale, seven-story, reinforced-concrete building slice. The method is based on monitoring changes in the velocity of waves propagating vertically through the structure, identified by least-squares (LSQ) fit of beam models. The experiment was conducted by a team from the University of California,...
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Stateczność samopodnoszących pełnomorskich platform wiertniczych w fazie eksploatacji
PublikacjaWspółczynnik bezpieczeństwa platformy Petrobaltic na moment obrotowy (stateczność ogólna) oszacowany przy założeniu, że konstrukcja jest traktowana jako układ słupów połączonych sztywnym pokładem, z korekcją efektów drugiego rzędu. Przemieszczenie poziome pokładu platformy wyznaczone, stosując odpowiedni model MES. Siła krytyczna nogi obliczona przy założeniu jej utwierdzenia w dnie morza. Wpływ odchyłki od idealnej geometrii rur...
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Application a laboratory stand for multi-symptoms tests for high cyclic fatigue of constructional material
PublikacjaThis paper describes a need of diagnostics present ship plants according to current technical state. In order to reach competent physical quantity describing fatigue of materials by congregated energy. This paper describes using some diagnostics methods (acoustic emission AE, vibration, thermovision, deformation) in order to definition fatigue state of construction material. The author tries to find correlation between measured...
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Experimental study on earthquake-induced pounding between steel structures
PublikacjaPounding between adjacent structures has been repeatedly observed during major earthquakes. The phenomenon may cause some local damage at the points of interactions, it may also lead to substantial destruction, permanent deformations or total collapse of colliding structures. The effects of earthquake-induced structural pounding have been studied for more than three decades now. However, most of the studies concerned masonry as...
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The IPV6 Deployment - Best practices
PublikacjaThe new Internet Protocol IPv6 has been regarded for quite a long time as the only option to ensure uninterrupted operation for the Internet service providers andend-users in the current Internet. The article presents important faets about the IPv6, including current statistics of the IPv4 usage, the IPv6 statistics for Poland comparing to the whole Internet. Moreover, this paper shows important aspeets of migration from IPv4 towards...
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ECONOMICAL AND SAFE METHOD OF GRANULAR MATERIAL STORAGE IN SILOS IN OFFSHORE PORT TERMINALS
PublikacjaThe article discusses issues related with storage of granular materials in silos made of corrugated sheets and reinforced with vertical ribs. Advantages and disadvantages of these structures are named, and typical technological solutions used by largest silo producers are presented. Moreover, basic assumptions of Eurocode 3 are discussed in the context of determining the buckling load capacity of a ribbed jacket. Alternative methods...
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Prognozowanie wpływu drgań komunikacyjnych na budynki mieszkalne za pomocą sztucznych sieci neuronowych i maszyn wektorów wspierających
PublikacjaDrgania komunikacyjne mogą stanowić duże obciążenie eksploatacyjne budynku, powodując zarysowania i spękania tynków, odpadanie wypraw, zarysowania konstrukcji, pękanie elementów konstrukcji lub nawet zawalenie się budynku. Pomiary drgań na rzeczywistych konstrukcjach są pracochłonne i kosztowne, a co ważne nie w każdym przypadku są one uzasadnione. Celem pracy jest analiza autorskiego algorytmu, dzięki któremu z dużym prawdopodobieństwem...
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KONFIGURACJA SIECI LAN TYPU SOHO DO PRACY W INTERNECIE IPv6
PublikacjaArtykuł przedstawia podstawowe problemy występujące przy migracji środowisk małych sieci do obsługi protokołu IPv6. Wraz z problemami przedstawione zostały propozycje metodologii przeprowadzenia migracji i narzędzia wspomagające ten proces. Przedstawiono system wspierający administratorów w migracji zarządzanych przez nich sieci do obsługi protokołu IPv6. Celem pracy jest analiza problemów procesów migracji IPv4 do IPv6 oraz wskazanie...
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Selection of Organic Coating Systems for Corrosion Protection of Industrial Equipment
PublikacjaThe most important element of corrosion protection in industrial conditions is the protective coating system. However, selecting the right coating can often be a real problem due to the sheer number of coating manufacturers and their products on the market. A quantitative approach based on the data mining technique used to analyze the obtained multi-site exposure data has been proposed. This was demonstrated by the example of the...
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A Surveillance Of Dynamic Processes in Selected Mechatronic Systems
PublikacjaThe paper concerns development of original method of optimal control at energy performance index and its application to dynamic processes surveillance of some mechatronic systems. The latter concerns chatter vibration surveillance during highspeed slender milling of rigid details, as well as motion control of two-wheeled mobile platform. Results of on-line computer simulations and real performance on the target objects reflect...
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Wykorzystanie sztucznych sieci neuronowych do szacowania wpływu drgań na budynki jednorodzinne
PublikacjaW artykule przedstawiono metodę prognozowania wpływu drgań na budynki mieszkalne z wykorzystaniem sztucznych sieci neuronowych. Drgania komunikacyjne mogą doprowadzić do uszkodzenia elementów konstrukcyjnych, a nawet do awarii budynku. Najczęstszym efektem są jednak rysy, pękanie tynku i wypraw. Metody oparte na sztucznej inteligencji są przybliżone, ale stanowią wystarczająco dokładną i ekonomiczną alternatywę dla tradycyjnych...
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Luminescence properties of Eu3+ and Tb3+ doped silica-based xerogels
PublikacjaPure SiO2 xerogels and SiO2 xerogels containing SrF2: Eu3+/: Tb3+ crystals were prepared using sol-gel method. Luminescent spectra showed excitation and emission peaks characteristic to Eu3+ and Tb3+ 4f - 4f transitions. ET Tb3+→Eu3+ has been observed. XRD pattern of SiO2 matrix confirmed lack of long range order. Patterns of SiO2-SrF2:Eu3+ and SiO2-SrF2:Tb3+ showed peaks corresponding to SrF2. SEM images have shown agglomerates...
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Dynamic analysis of temporary steel grandstand equipped with different types of bracing system
PublikacjaIn the paper, behaviour of a temporary steel grandstand equipped with two different types of bracing system has been analysed through the numerical study. A typical solution concerning application of a diagonal tubular members has been compared with elements proposed by authors and called polymer dampers. A polymer element consists of two L-shape steel members bonded with polymer mass. The aim of the paper is to verify the effectiveness...
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Study of Soil Temperature and Moisture Changes in a Physical Model of an Underground Cable Line
PublikacjaThe ampacity of power cables is highly dependent on the thermal resistivity of the soil in which they are laid. The lower it is, the higher this ampacity. The thermal resistivity of the soil decreases as its moisture increases. Therefore, it is preferable that the soil around the cables has high moisture. Unfortunately, the heat generated in heavily loaded cables causes the migration of moisture from the surrounding soil, which...
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Identification of hydroacoustic wave sources of ship in motion
PublikacjaThis paper deals with results of identification tests of acoustic field spectrum of underwater noise generated by ship in motion. The field is connected with acoustic activity of ship mechanisms and devices in operation. Vibration energy generated by the mechanisms and devices is transferred through ship structural elements to surrounding water where it propagates in the form of acoustic waves of a broad band of frequencies. In...
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Launching of steel bridge girder. Application of nonlinear shell models
PublikacjaThe paper describes the final technology of launching the steel bridge superstructure. The original technology failed in the first construction stage. Local damage of steel webs caused by plastic buckling stopped the procedure. In the effect of damage a new consulting team was employed to solve the problem and redesign a technology of constructing. The key element of the new solution was developed with great help of non-linear...
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SHM System of the Roof Structure of Sports Arena “Olivia”
PublikacjaThe paper presents a structural health monitoring system of the Sports Arena “Olivia” in Gdansk, Poland. The system was installed because of doubts about the roof stability due to observed buckling of the steel truss members. The SHM system was based on nonlinear FEM models used for detection of type of near failure modes of the roof. The application of detailed FEM model in current state updated on data from in situ loading testes...
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Elemental and tight monogamy relations in nonsignaling theories
PublikacjaPhysical principles constrain the way nonlocal correlations can be distributed among distant parties. These constraints are usually expressed by monogamy relations that bound the amount of Bell inequality violation observed among a set of parties by the violation observed by a different set of parties. We prove here that much stronger monogamy relations are possible for nonsignaling correlations by showing how nonlocal correlations...
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Nondestructive Testing of the Miter Gates Using Various Measurement Methods
PublikacjaWhen any problems related to civil engineering structures appear, identifying the issue through the usage of only one measuring method is difficult. Therefore, comprehensive tests are required to identify the main source. The strains and displacement measurements, as well as modal identification, are widely used in the nondestructive testing of structures. However, measurements are usually carried out at several points and confirm...
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Assessment of Subsoil Subsidence Under the Railway Surface with the Use of Fuzzy Sets
PublikacjaThe cause of the subsidence of the railway track is the subsidence of the track bed itself and it is often related to the subsidence of the subsoil. Such settlement leads to: uneven longitudinal railways and track twist. These phenomena have a negative impact on the comfort and safety of driving, and in extreme cases lead to a train derailment. It has been shown that the magnitude of these settlements is determined by many parameters...
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Design and Experiments of a Piezoelectric Motor Using Three Rotating Mode Actuators
PublikacjaThis paper represents a numerical and experimental investigation of the multicell piezoelectric motor. The proposed design consists of three individual cells that are integrated into the stator, double rotor, and a preload system combined into a symmetrical structure of the motor. Each of the cells is characterized by a traveling wave and rotating mode motor. A finite element numerical analysis is carried out to obtain optimal...
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Influence of nodes with positive eccentricity on load-carrying capasity of truss' top chords in trusses made of welded cold-formed members.
PublikacjaIn order to establish the influence of eccentric crossing of truss members on the load-carrying capacity of the folded chord of a hat-section truss, a research model was created and preliminary numerical analysis of the truss was performed with the use of Marc Mentat programme. Distorial instability of crossheads caused by deviation of loose (unmounted) channel section web’s bends was observed. Due to the slenderness of the section’s...
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THE METHOD OF MEASURING THE MEMBRANE COVER GEOMETRY USING LASER SCANNING AND SYNCHRONOUS PHOTOGRAMMETRY
PublikacjaThe authors present the experience and results of field studies carried out at the technical acceptance of Forest Opera (name in Polish: Opera Leśna) in Sopot (Poland). An unusual design of covering made in the form of “Sheerfill I” technical fabric membrane required spanned in the form of sails, required the use of terrestrial laser scanning. Such approach allowed for the fast and accurate record of the surface of individual panels...
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FT-IR studies of molecular interactions in formamide-methanol mixtures
PublikacjaTechniką ATR zmierzono widma FT-IR roztworów metanolu(MeOH) i formamidu(FA) w całym zakresie ich składu. Przeprowadzono analizę faktorową widm, która wykazała obecność dwóch kompleksów molekularnych matanolu z formamidem. Na podstawie profilów stężeniowych indywiduów absorbujących wyznaczono średni skład kompleksów w zależności od składu mieszaniny. Przeprowadzono również analizę pasma CO formamidu metodą widm różnicowych. Wyniki...
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Role of nitrogen in evolution of sp2/sp3 bonding and optical band gap in hydrogenated carbon nitride
PublikacjaDrastic changes in the bonding are found in amorphous hydrogenated carbon nitride (a-CNx:H) film as a function of nitrogen concentration (or N/C ratio). The total C-sp3 fraction and hardness shows a sharp decrease (at N/C = 0.40) whereas optical band gap and resistivity shows a gradual increase as nitrogen concentration increases from 0.07 to 0.58. Raman spectrum of a-CNx:H film is fitted with both Gaussian (integrated intensity...
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Own or public? Later livelihoods of Ukrainian war migrant households in Poland
PublikacjaThis paper presents empirical research on the livelihood resources of Ukrainian households that fled to Poland due to the Russian invasion and reside there long term. Using a nationwide sample of these households and an accurate econometric framework, we investigate the factors influencing the role of income from work, other private resources and public assistance in covering their living costs in exile. Our findings confirm the...
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Vibration surveillance in the hybrid system using optimal control at energyperformance index. W: Zagadnienia analizy modalnej konstrukcji mechanicz- nych. Praca zbiorowa pod red. T. Uhla. Kraków: Kated. Robotyki i Dynam. Masz. AGH**2003 s. 107-114, 2 rys. 1 tab. bibliogr. 4 poz. Nadzorowanie drgań w układzie hybrydowym z wykorzystaniem strerowania opty- malnego przy energetycznym wskaźniku jakości.
PublikacjaW pracy rozważano nadzorowanie drgań niestacjonarnych układów mechanicznychza pomocą sterowania optymalnego przy energetycznym wskaźniku jakości. Uwzględnienie założenia o możliwości podziału układu na podukład modalny, pod-układ strukturalny oraz podukład łączący umożliwiło opis układu sterowanego we współrzędnych hybrydowych. Rozważania zilustrowano przykładem nadzorowa-nia drgań pomostów wagi kolejowej podczas przejazdu wagonów.
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Theoretical study of the photoelectron spectrum of ethyl formate: Ab initio and density functional theory investigation
PublikacjaThe first ionization energy and associated photoelectron spectrum of ethyl formate are investigated with quantum chemistry calculations. The geometries, harmonic vibrational frequencies and first ionization energy are computed at the Hartree-Fock (HF) and at the second order Moller-Plesset perturbation theory (MP2). Moreover, accurate ionization energies are obtained with the Coupled-Cluster theory including singles and doubles...
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Nonlinear generation of non-acoustic modes by low-frequency sound in a vibrationally relaxing gas
PublikacjaTwo dynamic equations referring to a weakly nonlinear and weakly dispersive flow of a gas in which molecular vibrational relaxation takes place. are derived. The first one governs an excess temperature associated with the thermal mode, and the second one describes variations in vibrational energy. Both quantities refer to non-wave types of gas motion. These variations are caused by the nonlinear transfer of acoustic energy into...
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Load test of new European record holder in span length among extradosed type bridges
PublikacjaThe article presents acceptance load tests of a newly built extradosed MS-3 bridge located along the national road DK-16 near Ostróda (Poland). The structure features significant dimension in European reference scale. It is a new record holder in span length regarding this distinct bridge category. Its length ranges 206 m. Static and dynamic load tests were performed here. The program was extended by entire structural laser scanning...
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On Configurability of Distributed Volunteer-Based Computing in the Comcute System
PublikacjaThe chapter proposes additional solutions that can be implemented within the Comcute system to increase its configurability. This refers to configuration of the reliability level in the W and S server layers, static or on-the-fly data partitioning and integration, configuration of the system for processing in the data streaming fashion, extending the system for selection of a project that the client wants to contribute to, ease...
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The modelling method of discrete-continuous systems
PublikacjaThe paper introduces a method of discrete-continuous systems modelling. In the proposed method a three-dimensional system is divided into finite elements in only two directions, with the third direction remaining continuous. The thus obtained discrete-continuous model is described by a set of partial differential equations. General difference equations of discrete system are obtained using the rigid finite element method. The limit...
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Modelling and Identification of Tower Type Historic Buildings
PublikacjaW pracy omawia się problemy modelowania i identyfikacji zabytkowych murowanych budowli wieżowych na przykładzie wieży Twierdzy Wisłoujście. Przedstawiono analizę modalną na podstawie dwukierunkowych pomiarów przyspieszeń na 9 poziomach wieży. Wyniki analizy posłużyły do identyfikacji modelu matematycznego budowli w postaci sztywnego bloku na podłożu sprężystym. Wykorzystano hierarchiczną procedurę opartą na analizie wrażliwości.
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Dynamics of mechanical model of implant-tissue system in ventral hernia repair
PublikacjaThe paper deals with a finite element modelling of implants in the problem of ventral hernia repair. The synthetic mesh implanted in the abdomen during surgery is here modelled as a membrane structure. Thesystem undergoes the internal abdominal pressure that occurs during the postoperative cough, the load identified in the literature as the main cause of the connection failure and hernia recurrence. The model can be used to estimate...
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Hybrid Reduced Model of Continuous System
PublikacjaThe paper introduces an alternative method of modelling and modal reduction of continuous systems. Presented method is a hybrid one. It combines the advantages of modal decomposition method and the rigid finite element method. In the proposed method continuous structure is divided into one-dimensional continuous elements. For each 1D element modal decomposition and reduction is applied. Interactions between substructures are...
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Influence of Additional Loads on Chosen Gait Parameters and Muscles Activity
PublikacjaThis paper is devoted to human motion analysis and comparison of chosen kinematics parameters during normal gait with and without additional load in a form of backpack. A stability in both cases were compared in both frontal and sagittal planes, by applying a video tracking system. Experimental tests performed on treadmill, passive markers, placed on volunteers bare skin were used. Additionally, an infra-red camera was employed...
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Timber-frame house resistant to dynamic loads - analysis of wall panel filled with polyurethane foam
PublikacjaThe present study shows the experimentally and numerically determined response of a single timber-frame house wall panel filled with polyurethane (PU) foam under dynamic loads. The harmonic tests were conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified displacement. Based on the results of the comparison between the experimental tests and the numerical analyses, the numerical...
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Conditions for Multiple Acquisition of Echoes from Stationary Targets in Successive Transmissions of Active Sonars
PublikacjaIn echolocation, the highest possible number of contacts with a detected target is clearly decisive on the possibilities of echo processing to optimise the estimation of distinctive characteristics of the observed target. In hydrolocation, the slow propagation of acoustic waves in water reduces the number of contacts of echosounders and sonars with detected targets. The article considers model conditions for acquiring multiple...
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Noise effect on parameters of quiet sonar with code modulation
PublikacjaEarlier publications of the paper authors have shown that the use of code keying mixed with the CW FM sound signal allows the significant reduction in the distance measurement error, compared to classic silent CW FM sonar. In addition to the code modulation parameters, the magnitude of this error is influenced by the received input acoustic noise. The article shows the dependence of the input signal-to-noise ratio and the sound...