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EN
This article presents research conducted on various polymer models imitating biological structures. Tests were conducted using a newly developed research method described in [1]. The purpose of our research was to check if the measuring system [1] is able to distinguish multilayer samples. Test materials were two different polymer models which were subjected to pressure in the central point. Marked points on the external surface of the sample were followed during the measurement. The arrangement of points on the image allowed to reconstruct the 3D surface of the sample and to determine the displacement of the analysed points. Measurements were repeated 10 times to ensure the representativeness (credibility) of the conducted research. Statistical tests and artificial neural networks (ANN) were used to classify the examined samples. We used 5-fold cross-validation for training and validating the ANN. The entire set of 75 cases was divided into 5 equinumerous subsets. The obtained results suggest that the proposed method distinguished between the tested samples on the basis of results. Analysed materials react differently to the given mechanical factor.
EN
The article reports the application of the mathematical theory of hysteresis to soil dynamics to characterise its behaviour under the action of cyclic loads. Based on appropriate laboratory experiments for a given soil, the achieved values were verified in simulations. The cycle shapes of stress–strain shear response for all strain levels and different combinations of static and cyclic shear stress loading were replicated. For proper characterisation in the case of repeated loads, the model incorporates the phenomenon of degradation of the structure and generation of excess pore pressure in considering its continuous variation throughout the loading process using an energy approach. The model is defined by parameters with physical interpretations that are evident from the tests.
PL
W pracy przeprowadzono analizę wpływu materiału osnowy na właściwości magnetyczne miękkich materiałów kompozytowych (SMC). Badania przeprowadzono na próbkach rdzeni cylindrycznych wykonanych przez autorów z mieszaniny proszku żelaza i różnego rodzaju osnowy. Badania obejmowały wyznaczenie takich parametrów jak indukcja nasycenia Bs, natężenie koercji Hc i stratność. Pomiary wykonano przy różnej częstotliwości wymuszenia.
EN
Soft magnetic composites are often used in the design of electromagnetic converters and electrical machines. Their popularity is due to the ease of molding and the ability to adapt to specific applications. The paper presents magnetic properties of cores made of iron powder and different type of binder. Samples were prepared by compression in temperature dependent from binder / Fe powder mix. Measurement of magnetic parameters revealed an change in magnetic properties with using various types of binders. The presented measurement data show that it is possible to produce of SMC cores with good magnetic properties, using readily available components and in uncomplicated production processes. Cylindrical cores were made with different types of binders, respectively: powder of suspense polyvinyl chloride, powder of polytetrafluoroethylene, powder of polyethylene wax and transformer oil. For the prepared samples we have determined their basic magnetic properties. The analysis of collected measurement data showed a significant relationship between SMC sample forming parameters and their magnetic properties. In addition, the measurements showed a poor dependence of the magnetic properties in developed SMC samples on the excitation frequency. The method of producing a polymer-metal composite described in the article is the subject of patent application P.420850.
4
Content available Investigation of the memristor nonlinear properties
EN
The study of nonlinear systems is an important research topic for scientists and researchers. Memristor, for a long time, it remained just as a theoretical element and rarely appeared in the literature because of having no simple and practical realization. In this paper, we reviewed the theoretical substantiation of the memristor and conducted a practical study of its nonlinear properties using the memristor company KNOWM of series BS-AF-W 16DIP. We also investigated the characteristics of the memristor via the LabView environment.
PL
Badanie systemów nieliniowych jest ważnym tematem dla badaczy i naukowców. Memrystor przez długi czas pozostawał elementem teoretycznym i rzadko pojawiał się w literaturze z powodu braku prostej i praktycznej realizacji. W tym artykule zostały przedstawione teoretyczne uzasadnienie memrystora i badania jego właściwości nieliniowych na przykładzie memrystora firmy KNOWM serii BS-AF-W 16DIP. Zostały przeprowadzone badania charakterystyk memrystora w środowisku LabView.
EN
This paper addresses the problem of modeling the nonlinear coil used for ferroresonant circuit analysis. The effect of ferroresonance is described and a general modeling approach is presented. The hysteresis modeling problem is also shortly discussed, on the example of a ferromagnetic coil. A brief overview of available literature and contributors to this area are provided. A series RLC circuit supplied from an AC source is discussed. The application of the fractional derivative in the modeling of an iron core coil is presented and suggestions of model implementations are given. The computations performed are illustrated by means of waveform data obtained from computer simulations and compared with those obtained from measurements performed in a specially prepared laboratory setup.
6
Content available Open loop control of piezoelectric tube transducer
EN
This paper is focused on the open loop control of a piezoelectric tube actuator, hindered by a strong hysteresis. The actuator was distinguished with 22 % hysteresis, which hinders the positioning of piezoelectric actuator. One of the possible ways to solve this problem is application of an accurate analytical inversed model of the hysteresis in the control loop. In this paper generalized Prandtl-Ishlinskii model was used for both modeling and open loop control of the piezoelectric actuator. Achieved modeling error does not exceed max. 2.34 % of the whole range of tube deflection. Finally, the inverse hysteresis model was applied to the control line of the tube. For the same input signal (damped sine 0.2 Hz) as for the model estimation the positioning error was max. 4.6 % of the tube deflection. Additionally, for a verification reason three different complex harmonic functions were applied. For the verification functions, still a good positioning was obtained with positioning error of max. 4.56 %, 6.75 % and 5.6% of the tube deflection.
EN
Measurements of dynamic surface tension were carried out in aqueous systems (water or 0.1 mM Triton X-100) comprising nanoparticles formed from chemically modified polyaldehyde dextran (PAD). The nanostructures, considered as potential drug carriers in aerosol therapy, were obtained from biocompatible polysaccharides by successive oxidation and reactive coiling in an aqueous solution. The dynamic surface tension of the samples was determined by the maximum bubble pressure (MBP) method and by the axisymmetric drop shape analysis (ADSA). Experiments with harmonic area perturbations were also carried out in order to determine surface dilatational viscoelasticity. PAD showed a remarkable surface activity. Ward-Tordai equation was used to determine the equilibrium surface tension and diffusion coefficient of PAD nanoparticles (D = 2.3×10-6 m2/s). In a mixture with Triton X-100, PAD particles showed co-adsorption and synergic effect in surface tension reduction at short times (below 10 s). Tested nanoparticles had impact on surface rheology in a mixed system with nonionic surfactant, suggesting their possible interactions with the lung surfactant system after inhalation. This preliminary investigation sets the methodological approach for further research related to the influence of inhaled PAD nanoparticles on the lung surfactant and mass transfer processes in the respiratory system.
EN
This paper presents an experimental and numerical investigation on the steel plate shear walls with beam-only-connected web plates (SSW-BO). These systems feature an alternative to the traditional type of steel shear walls through separating the lateral load resisting system from the primary columns. A possible drawback of SSW-BO is its reduced shear capacity compared with fully-connected web plates. High yield strength (HYS) web plate may develop shear capacity of these systems. The seismic behavior of the SSW-BO systems are experimentally investigated under cyclic quasi-static loading and compared considering two material properties and two different circular opening ratios. Shear strength, ductility, and energy dissipation capacity of HYS panels are higher than those of low yield strength (LYS) panels by as much as roughly 70%, 10% and 30%, respectively. The use of HYS web plates in SSW-BO systems appeared to be a promising solution to compensate the concerns regarding the low shear capacity and low energy dissipation resulting from separation steel plate from the columns. Moreover, the finite element software ABAQUS was used to investigate the behavior of SSW-BO systems by nonlinear analysis. A comparison between the experimental and numerical results showed excellent agreement.
EN
Our work involved experimental study of the influence of actomyosin complexes and the main structural components of the myocardial tissue – connective tissue collagen framework and cardiomyocytes – on the characteristics of viscoelastic hysteresis at different frequencies. In this paper a new method was introduced for the analysis of the viscoelastic characteristics of the force hysteresis in the isolated myocardial preparation for the assessment of mechanical energy expenditure in the tension-compression cycle. We established that basic myocardial structures have an impact on the to the characteristics of the viscoelastic hysteresis in many ways. It was shown that in rat’s myocardium cardiomyocytes one main factor that define the stiffness and viscosity of the myocardium in the physiological range of deformations, while binding of calcium ions with EGTA and calcium removal of sarcoplasmic reticulum with caffeine reduces viscoelasticity by ~30% and collagen framework is responsible for about 10% of viscoelasticity. It was revealed that in the physiological range of the hysteresis frequencies (3 to 7 Hz) expenditure of mechanical energy per unit of time increases linearly with increasing frequency. We proposed the structural and functional model that adequately describes the characteristics of the viscoelastic hysteresis in myocardial preparation in the range of strains and frequencies being under study.
EN
Bio-polyols based on rapeseed oil were used to produce flexible polyurethane foams (FPURF). The bio-polyols were obtained on a laboratory and industrial scale with the two-step method involving epoxidation of double bonds in rapeseed oil and opening of oxirane rings with different alcohols, such as isopropanol (iP) and diethylene glycol (DEG). The impact of bio-polyols production scale on selected physical and mechanical properties of FPURF was analyzed. The applied bio-polyols differed slightly by hydroxyl number, functionality, and water content. It was found that the scale of bio-polyol production has no significant impact on FPURF properties such as apparent density, hardness, hysteresis, support factor, and resilience. However, it was observed, that the addition of the bio-polyol to polyurethane (PUR) formulation had the impact on the FPURF properties as compared to the reference foams that were not modified with the bio-polyols. Moreover, a continuous method was used to prepare FPURF samples modified with different rapeseed oil-based polyols. For this purpose mixing-dosing device with conveyor line was used to synthesize the foams. It was found that the replacement of petrochemical polyols with the bio-polyols resulted in lower reactivity of the modified for- mulations and the amount of catalysts had to be increased. Furthermore, the foams hysteresis, support factor, and hardness were higher, especially for foams modified with the bio-polyol that contained DEG in its structure. Moreover, the fatigue tests were performed and the results showed a beneficial effect of the bio-based polyols on the functional properties, a.o. support factor of flexible foams.
PL
Bio-poliole z oleju rzepakowego, wytworzone w skali laboratoryjnej i przemysłowej, zastosowano wsyntezie elastycznych pianek poliuretanowych (FPURF). Bio-poliole otrzymano metodą dwuetapową przez epoksydację wiązań podwójnych w oleju rzepakowym, a następnie przez otwarcie pierścieni oksiranowych za pomocą izopropanolu (iP) oraz glikolu dietylenowego (DEG). Zbadano wpływ rodzaju bio-poliolu (także tego samego rodzaju, ale otrzymanego w różnej skali) na wybrane właściwości fizyczne i mechaniczne FPURF. Zastosowane bio-poliole różniły się między sobą nieznacznie liczbą hydroksylową, funkcyjnością i zawartością wody. Stwierdzono, że skala produkcji polioli nie ma istotnego wpływu na właściwości FPURF, takie jak: gęstość pozorna, twardość, histereza, współczynnik komfortu i odbojność. Zaobserwowano jednak wpływ modyfikacji za pomocą różnych bio-polioli na właściwości FPURF w porównaniu z właściwościami niemodyfikowanej pianki referencyjnej. Pianki FPURF otrzymano również stosując metodę ciągłą z użyciem urządzenia dozująco-mieszającego wraz zlinią do przesuwu form z mieszaniną reakcyjną. Stwierdzono, że zastąpienie polioli petrochemicznych bio-poliolami powoduje zmniejszenie reaktywności kompozycji poliuretanowych, co spowodowało konieczność zwiększenia ilości katalizatorów. Ponadto, zaobserwowano wzrost histerezy, współczynnika komfortu i twardości, szczególnie w wypadku pianek zawierających bio-poliol z wbudowanym DEG. Wyniki badań zmęczeniowych wykazały korzystny wpływ bio-polioli na właściwości użytkowe, m.in. na współczynnik komfortu pianek elastycznych.
11
Content available remote Simulation tests of relay valve in the context of its resistances to motion
EN
The article presents the description of the cylinder relay valve designed and made by the Rail Vehicles Institute "TABOR". The individual components of its construction were characterized and it was selected those that have the significant influence on change of resistances to motion of the relay valve. The currently applicable criteria concerning the operating parameters of the cylinder relay valve are presented. The selected results of the tests which consisted in determining the impact of resistances to motion on change of the hysteresis values and the correctness of operation of the relay valve are presented. The stand, on which the simulation tests of relay valve operation were carried out, and the stand for measurements of resistances to motion are shown. The article also presents a computer simulation model in which the results were verified.
PL
W artykule przedstawiono opis przekładnika ciśnienia cylindrowego zaprojektowanego i wykonanego przez Instytut Pojazdów Szynowych „TABOR”. Scharakteryzowano poszczególne elementy składowe jego budowy oraz wytypowano te, które mają istotny wpływ na zmianę oporów ruchu przekładnika ciśnienia. Przedstawiono aktualnie obowiązujące kryteria dotyczące parametrów działania przekładnika ciśnienia cylindrowego. Zaprezentowano wybrane wyniki badań, które polegały na ustaleniu wpływu oporów ruchu na zmianę wartości histerezy oraz poprawności działania przekładnika ciśnienia. Pokazano stanowisko, na którym przeprowadzono badania symulacyjne działania przekładnika ciśnienia oraz stanowisko do pomiarów oporów ruchu. W artykule przedstawiono także komputerowy model symulacyjny, w którym weryfikowano wyniki badań.
12
Content available remote Influence of a skin tissue anisotropy on mechanical hysteresis
EN
The mechanical properties of a pig’s skin as a human skin substitute in the studies carried out in vitro are used in surgery and engineering design. The investigation included the uniaxial tensile test and cyclic loading-unloading tests of a swine skin. The values of dissipated energy and energy dissipation ratio for first, fifth and tenth hysteresis loop of every examined sample were obtained. In the investigation, the skin anisotropy was taken into consideration. The estimation of the influence of various levels of load on the values of the measured parameters was also made.
PL
Właściwości mechaniczne tkanki skórnej świni jako substytutu skóry ludzkiej w badaniach in vitro są wykorzystywane w chirurgii i projektowaniu inżynierskim. Badania obejmowały przeprowadzenie próby jednoosiowego rozciągania oraz wykonanie testów cyklicznego obciążania-odciążenia dla skóry świni. Otrzymano wartości energii dyssypacji oraz współczynnika pochłaniania energii dla pierwszej, piątej i dziesiątej pętli histerezy mechanicznej każdej zbadanej próbki. We wszystkich przeprowadzonych badaniach uwzględniono anizotropową budowę tkanki skórnej. Oceniono także wpływ różnych poziomów zastosowanego obciążenia na wartości mierzonych parametrów.
13
Content available remote Pomiary dynamicznych pętli histerezy konstrukcyjnej stali prototypowej
PL
W niniejszej pracy przedstawiono sposób pomiaru dynamicznych pętli histerezy dla stali o nowatorskim składzie przeznaczonej na nabiegunniki maszyn elektrycznych, a szczególnie generatorów wiatrowych. Pomiary wykonano dla dwóch częstotliwości zasilania, a mianowicie f1=10 Hz oraz f2=50 Hz. Porównano wartości strat mocy w rdzeniu otrzymane z całkowania pola powierzchni pętli histerezy oraz metodą bezpośredniego pomiaru poboru mocy ze źródła zasilającego uzwojenie próbki stalowej.
EN
The measurement tests of the dynamic hysteresis loops for the innovative composition casting steel. In measurements designed for poles of the electrical machines, especially wind generators, were presented in this paper. The measurements were performed for two frequencies of power supplying f1=10 Hz and f2=50 Hz. The power core losses obtained by integration of the dynamic hysteresis loop surfaces have been compared with those obtained by direct measurements of the source power supplying the steel probe winding.
EN
Depending on the initial degree of saturation of a soil, different capillary pressure curves occur. If a sample is initially water saturated and then drained (process of drainage) the main drying curve results. On the other hand, if the sample is initially dry and water is supplied until saturation is reached (process of imbibition) the main wetting curve is the consequence. These two curves build a hysteresis loop. If after the first process the other is followed up (possibly a number of times), then inner hysteresis curves arise. The focus of this paper is the investigation of some aspects of the main drying curve (MDC) and the main wetting curve (MWC). Some methods of their measurement are discussed. Because of big differences in the capillary pressure for different degrees of saturation the measurement is laborious and time consuming and often application of more than one method is necessary. Consequently, often only the MDC is measured and the data is used to predict the MWC and inner curves. Exemplarily, one prediction method is shown and subsequently, for one soil type the resulting curves are used to calculate the wave speeds and attenuations of the appearing sound waves. The dependence of these wave features on frequency and saturation for the current example shows, that the hysteresis effect of the capillary pressure curve has only a slight effect on the propagation of sound waves in partially saturated sand.
EN
The paper presents the exact solution of the antiplane problem for an inhomogeneous bimaterial with the interface crack exposed to the normal load and cyclic loading by a concentrated force in the longitudinal direction. Using discontinuity function method the problem is reduced to the solution of singular integral equations for the displacement and stress discontinuities at the domains with sliding friction. The paper provides the analysis of the effect of friction and loading parameters on the size of these zones. Hysteretic behaviour of the stress and displacement discontinuities in these domains is observed.
16
Content available remote Wpływ wielkości histerezy przełączeń na przepustowość w sieci LTE
PL
W sieciach mobilnych użytkownicy są przełączani pomiędzy stacjami bazowymi na podstawie siły sygnału lub innych metryk jakości transmisji. W celu optymalizacji przełączeń pomiędzy stacjami bazowymi często wykorzystywana jest histereza. Pozwala ona ograniczyć liczbę niepotrzebnych, bardzo krótkich przełączeń. W artykule zbadano wpływ wielkości histerezy na liczbę przełączeń oraz na osiąganą przepustowość połączenia użytkownika sieci LTE wyznaczaną na podstawie poziomu sygnału. Wyniki przeprowadzonych symulacji wskazują, że odpowiedni margines przełączenia znacznie zmniejsza liczbę niepotrzebnych przełączeń, a jednocześnie praktycznie nie zmniejsza przepustowości.
EN
In wireless networks users are switched between base station basing on signal strength or other metrics. To optimize users’ handover between base stations commonly used is hysteresis. It reduces the number of unnecessary, very short handovers. In this paper we have evaluated influence of handover hysteresis on the number of handovers and average bitrate which is derived from signal-to-noise ratio. The results show that proper handover margin can notably reduce the number of unnecessary handovers almost without reducing the throughput of network.
EN
The paper presents numerical simulation of hysteretic live load effect in a soil-steel bridge. The effect was originally identified experimentally by Machelski [1], [2]. The truck was crossing the bridge one way and the other in the full-scale test performed. At the same time, displacements and stress in the shell were measured. The major conclusion from the research was that the measured quantities formed hysteretic loops. A numerical simulation of that effect is addressed in the present work. The analysis was performed using Flac finite difference code. The methodology of solving the mechanical problems implemented in Flac enables us to solve the problem concerning a sequence of load and non-linear mechanical behaviour of the structure. The numerical model incorporates linear elastic constitutive relations for the soil backfill, for the steel shell and the sheet piles, being a flexible substructure for the shell. Contact zone between the shell and the soil backfill is assumed to reflect elastic-plastic constitutive model. Maximum shear stress in contact zone is limited by the Coulomb condition. The plastic flow rule is described by dilation angle ψ = 0. The obtained results of numerical analysis are in fair agreement with the experimental evidence. The primary finding from the performed simulation is that the slip in the interface can be considered an explanation of the hysteresis occurrence in the charts of displacement and stress in the shell.
EN
The article presents the results of experimental studies focused on effect of setting background current on the hysteresis of the proportional directional control valve (D1FB series, manufactured by the Parker Hannifin).Described tests were performed according to the Fractional-Factorial Experiment Method (FFEM).In presented experiment influence of the background current, vibrations and the positioning accuracy of hydraulic receivers on pressure pulsations have been omitted.
PL
W artykule zaproponowano metodykę wypracowania modelu nieliniowości rdzenia transformatora w środowisku Simulink/SimPowerSystems w oparciu o eksperymentalnie wyznaczone pętle histerezy i pierwotne krzywe magnesowania realnego transformatora. Zweryfikowano jakość takiego modelu poprzez odniesienie wyników symulacji zachowania się transformatora w różnych scenariuszach obwodowych do wyników obserwacji realnego obiektu.
EN
In the paper the method for Simulink/SimPowerSystems nonlinear core transformer model parameterization based on real transformer core data observations is proposed. The quality of such a model was verified through comparison of simulated and real transformer behavior observations in different circuit scenarios.
20
EN
The article presents a new class of smart materials which are magnetic shape memory alloys. These alloys combines both good dynamics and large strains. These properties make it possible to use these materials in positioning transducers which are alternative for classical electromagnetic transducers such as proportional solenoids. Unfortunately as other smart materials, MSMA are distinguished by hysteresis phenomenon which loop in this case is very wide and asymmetric. Authors present result of strain measurement which was performed for decreasing amplitude sine input signal. Based on this result phenomenological generalized Prandtl-Ishlinskii model was matched and compared.
PL
Artykuł zawiera opis nowej grupy materiałów inteligentnych, jaką są materiały z magnetyczną pamięcią kształtu. Materiały te łączą w sobie dobre właściwości dynamiczne oraz duży zakres możliwych odkształceń. Właściwości te powodują, iż istnieje realna szansa na praktyczną ich aplikację w konstrukcji przetworników pozycjonujących, które mogą konkurować z rozwiązaniami klasycznymi np. elektromagnesami proporcjonalnymi. Autorzy zaprezentowali wynik pomiaru wydłużenia dla gasnącej amplitudy sinusoidalnego sygnału sterującego. Na podstawie zarejestrowanych wyników dopasowano do nich uogólniony fenomenologiczny model histerezy Prandtla-Ishlińskiego oraz dokonano porównania.
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