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EN
The aerodynamic research into models of an aircraft aims at creating the main characteristics of aerodynamic forces and moments and the aerodynamic characteristics of coefficients of aerodynamic forces and moments, based on real dimensions. The method of 3D printing was used to create a model of an aircraft. The model with the previously set printing parameters and commands for a 3D printer, in the right order, was imported into MakerBot Print. The final stage was printing the model. The printed components of the model of an aircraft were imperfect due to the incorrectly set printing parameters. The model with the previously set printing parameters and commands for a 3D printer, in the right order, was imported into MakerBot Print. The final stage was printing the model. The printed components of the model of an aircraft were imperfect due to the incorrectly set printing parameters. The printing parameters were corrected in the next printing sessions so the surfaces of the components were good enough and grinding was unnecessary. Some excess material was removed in each of the printed components, and the slots were cleaned. Then, the individual models were put together. The article describes the technique of creating a model of an aircraft to map its exact geometry for experimental wind tunnel research. 3D printing enables us to experimentally investigate a created geometry, in particular to investigate further prior to releasing an aircraft to service. The 3D model employs the model created in line with the previous CFD analysis.
EN
The paper presents experimental and numerical results of the stamping process of an axially-symmetrical element. The subject of the study was a sample made of a 0.47 mm thick aluminium alloy Al-1100 sheet. Experimental studies were conducted on a universal testing machine, while numerical simulations were carried out on two different numerical software programs Abaqus® and Deform-3D. The results obtained from the numerical analysis allowed to develop a numerical model of the stamping process.
PL
W artykule przedstawiono wyniki badań eksperymentalnych i numerycznych procesu tłoczenia elementu osiowo-symetrycznego. Przedmiotem badań była próbka wykonana ze stopu aluminium Al-1100 o grubości 0,47 mm. Badania doświadczalne przeprowadzono na uniwersalnej maszynie wytrzymałościowej, natomiast symulacje numeryczne zrealizowano w dwóch różnych programach komputerowych Abaqus® oraz Deform-3D. Wyniki uzyskane z analizy numerycznej pozwoliły na opracowanie numerycznego modelu procesu tłoczenia.
EN
The paper proposed a numerical model of a shear connection between a reinforced concrete slab and a steel shape. The connection was made using a top-hat profile. A method for conducting experimental research on shear connections in the composite structures was presented. Geometric dimensions and material parameters of the analysed model of connection, on which the experimental research was conducted, were noted. The results of the conducted experimental research were compared to the results of the numerical analysis performed using ANSYS software. displecement curves were analysed for both cases and any correlation between experimental and numerical results was noted.
PL
W pracy zaproponowano model numeryczny połączenia ścinanego płyty żelbetowej z kształtownikiem stalowym. Zespolenie wykonano przy użyciu łącznika kapeluszowego. Przedstawiono sposób prowadzenia badań doświadczalnych połączeń ścinanych w konstrukcjach zespolonych. Podano wymiary geometryczne oraz parametry materiałowe analizowanego modelu połączenia, dla którego wykonano badania eksperymentalne. Porównano wyniki przeprowadzonych badań doświadczalnych z wynikami analizy numerycznej wykonanej przy użyciu programu ANSYS. Przeanalizowano przebieg krzywych poślizgu dla obu przypadków wskazując korelację między wynikami doświadczalnymi i numerycznymi.
PL
Elementem pomiarowym przepływomierza jest kolano rurowe, które znajduje się w praktycznie każdej instalacji przemysłowej. Kolano, jako element już istniejący w instalacji, nie wprowadza dodatkowych strat ciśnienia. Metoda ta choć mało popularna stanowi często jedyną możliwość pomiaru strumienia cieczy. Celem niniejszej pracy jest sprawdzenie możliwości i dokładności wyznaczenia charakterystyki przepływomierza kolanowego bez przeprowadzania kalibracji na obiekcie rzeczywistym. Praca obejmuje wyznaczenia charakterystyki rzeczywistego kolana segmentowego w oparciu o badania modelu laboratoryjnego i obliczenia numeryczne CFD.
EN
The measuring element of the flowmeter is a tubular bend which can be found in practically every industrial installation. Tubular bend, as an element already existing in the installation, does not bring additional pressure losses. This method, although not popular, is often the only way to measure the liquid stream flow. The purpose of this paper is to check the ability and accuracy of characteristic designation for the knee-shaped flow meter without calibration on a real object. Article includes the determination of the actual segmental tubular bend characteristics based on laboratory model and numerical CFD calculations.
EN
Purpose: The aim of the work was to analyse the critical state of thin-walled composite profiles with top-hat cross section under axial compression. Design/methodology/approach: The purpose of the work was achieved by using known approximation methods in experimental and finite element methods for numerical simulations. The scope of work included an analysis of the behavior of thin-walled composite structures in critical state with respect to numerical studies verified experimentally. Findings: In the presented work were determined the values of critical loads related to the loss of stability of the structures by using well-known approximation methods and computer simulations (FEM analysis). Research limitations/implications: The research presented in the paper is about the potential possibility of determining the values of critical loads equivalent to loss of stability of thin-walled composite structures and the future possibility of analyzing limit states related to loss of load capacity. Practical implications: The practical approach in the actual application of the described specimen and methodology of study is related to the necessity of carrying out of strength analyzes, allowing for a precise assessment of the loads upon which the loss of stability (bifurcation) occurs. Originality/value: The originality of the research is closely associated with used the thinwalled composite profile with top-hat cross-section, which is commonly used in the fuselage of passenger airplane. The methodology of simultaneous confrontation of the obtained results of critical loads by using approximation methods and using the linear eigenvalue solution in numerical analysis demonstrates the originality of the research character. Presented results and the methodology are intended for researchers, who are concerned with the topic of loss of stability of thin-walled composite structures.
6
Content available remote Experimental modal analysis of the turbine blade
EN
In this paper the results of an experimental modal analysis of the turbine blade were presented. Investigations were made using the electrodynamic vibration system. As the results of analysis, the resonant frequencies of the blade were performed. The results of experimental investigations are dependent on many parameters of vibration system defined before the start of the test. In the first part of this study the influence of the frequency sweep rate on values of blade resonant frequency was investigated. In the next part of the work the effect of excitation intensity on value of the blade vibration amplitude was investigated. The stiffness of the grip used for fixation of the blade to the movable shaker head can have a large influence on the results of an experimental modal analysis. The fir tree slots of the blade were compressed in the grip using a special screw with fine thread. In the last part of the work the influence of the torque used for screw home on results of the modal analysis of the blade was examined. As the results of performed investigations the final conclusions were formulated.
PL
Praca przedstawia wyniki eksperymentalnej analizy modalnej łopatki turbiny silnika lotniczego. Badania przeprowadzono za pomocą systemu wibracyjnego. Jako wyniki przedstawiono analizę modalną i częstotliwości rezonansowych łopatki turbiny. Uzyskane rezultaty badań eksperymentalnych są zależne od wielu czynników definiowanych na wstępie testu. W pierwszej części pracy określono wpływ prędkości przemiatania oraz intensywności wymuszenia na wartość częstotliwości rezonansowej łopatki turbiny. W następnej części pracy badano wpływ intensywności wymuszenia na wartość amplitudy wibracji łopatki. Jednym z istotnych parametrów mających wpływ na częstotliwości rezonansowe uzyskane w badaniach doświadczalnych jest sztywność uchwytu służącego do zamocowania łopatki do głowicy wzbudnika. Połączenie jodełkowe łopatki zostało utwierdzone przez docisk realizowany za pomocą śruby z gwintem drobnozwojnym, zapewniającym uzyskanie dużych sił docisku przy ograniczonej wartości momentu dokręcenia. W ostatniej pracy określono także wpływ momentu dokręcenia śruby dociskowej na wartości uzyskanych częstotliwości rezonansowych łopatki. Na podstawie przeprowadzonych badań sformułowano wnioski końcowe.
PL
W artykule zwrócono uwagę na rosnący deficyt kruszywa łamanego ze skał litych. Deficyt oraz koszty transportu tego typu kruszyw z południa Polski w znacznym stopniu utrudniają realizację znaczących inwestycji regionu Warmii i Mazur, zwłaszcza w drogownictwie. W oparciu o wyniki badań przeprowadzonych przez autorów oraz rezultaty badań publikowanych autorzy wykazują, że kruszywa naturalne z kopalń woj. warmińsko-mazurskiego spełniają wymagania stawiane kruszywom drogowym i popierają ich zastosowanie w elementach konstrukcji nawierzchni. Zwracają także uwagę na możliwość zmniejszenie nakładów finansowych przy realizacji takich inwestycji w regionie Warmii i Mazur.
EN
The article notes the fact that an expanding deficit appears, when it comes to the crushed-stone aggregate created with the use of rocks. Deficit and costs of transport pertaining to such aggregate, with shipments being sent from the southern part of Poland, make it significantly more difficult to implement relevant investments in the Warmian-Masurian region, especially when it comes to the road infrastructure. On the basis of the results of the research carried out by the authors, and the results of the research which had been already published, the researchers make an attempt at proving that natural aggregate coming from the mines located in the Warmian-Masurian Voivodeship meet the requirements defined for the road-building aggregate. The authors endorse application of the said aggregate in the works related to creation of new road surfaces. The Article also stresses the possible reduction of the financial expenditure, when such investments are realized in the Warmian-Masurian region.
EN
In steady-state conditions when the fluid temperature is constant, there is no damping and time lag so the temperature measurement can be performed with a high accuracy. But when the fluid temperature is varying rapidly as during the start-up, quite appreciable differences occur between the exact and measured temperature because of the time required for the transfer of heat to the thermocouple placed inside a thermometer pocket. The temperature of the fluid is one of the key parameters affecting the proper operation of thermodynamic cycles, so the precise determination of its value is very important. The speed of the response of control systems to a temperature change is closely related to the time constant of the used thermocouples. The paper presents a significant impact of fluid velocity changes (in this case air) on the value of time constants of thermometers. For this purpose, the experimental study was carried out using sheathed thermometers with different diameters and hot junctions. The time constants determined for various thermometers are compared.
EN
In this work, the influence of the engine rotational speed on the natural frequencies of the turbine blade was investigated. In first part of the work the experimental modal analysis of the blade were made using the vibration system. The investigated blade was fixed to the movable head of the shaker. The blade amplitude was measured using the piezoelectric accelerometers. As results of experimental modal analysis, the resonant frequencies for first three modes of vibration were determined. In the next step of the work, the numerical models of the blades with different size of the finite elements were performed in order to check the convergence of the numerical solution. For each models the natural frequencies were determined for the non-rotated blade. The numerical results were next compared to the results of experimental modal analysis. After this comparison, one model only was selected for the further computations. In the last part of the work, the complex multi-steps analysis was performed in order to investigate the influence of turbine rotational speed on the modes and natural frequencies of the blade. Obtained results are important from both the research and also the practical point of view and have an influence on reliability of the engine.
EN
The thermo-magnetic convection of paramagnetic fluid in a strong magnetic field is studied. The fluid is aqueous solution of glycerol with gadolinium nitrate hexahydrate. Experimental enclosure – rectangular vessel with aspect ratio equal to 2 – was heated from the bottom, and cooled from the top. Temperature difference between top and bottom walls was kept constant ΔT=5K. The magnetic induction was increased stepwise from 1 to 10 [T]. On the basis of temperature measurements, analysis of heat transfer and fluid flow were performed, showing that magnetic field strongly enhance heat transfer (over 300%) and that aspect ratio of the enclosure has a great influence on heat exchange in the system.
EN
The research include information about impact size of the drum for behaviour of the bed. Research carry out for 5 various degree of the drum filling range from 15 to 35%. Analyzed data of the experimental and estimated results shows difference. The biggest distinction noticed for maximum velocity - 19,8 rpm (for drum with a diameter of 700 mm).
PL
Do prowadzenia nieliniowych analiz konstrukcji żelbetowych jest niezbędne obliczanie sztywności i zależności moment–krzywizna elementów. Analiza ta wymaga licznych uproszczeń, gdyż sztywność silnie zależy od zarysowania elementu. Dlatego rozwiązania teoretyczne powinny być poddawane weryfikacji doświadczalnej. Przedstawiono możliwość prowadzenia weryfikacji z zastosowaniem skanera optycznego 3D.
EN
Calculation of the stiffness, or relation: the bending moment-curvature, of the reinforced concrete elements, is necessary to carry out the nonlinear analysis of structures. Because the rigidity of the element strongly depends on the level of cracking, such analysis requires a number of simplifying assumptions. Hence, the theoretical solutions have to be subjected to experimental verification. In the paper, the effective method to conduct such experimental verification, using optical scanner 3D, is shown.
PL
Artykuł prezentuje doświadczenie autora i jego osobiste poglądy na wyzwania, które wynikają z nowych trendów w projektowaniu – Free Form Design (FFD). W oparciu o uzyskane doświadczenie można było zidentyfikować zagrożenia dla systemu konstrukcyjnego, jakie niesie ze sobą nieskrępowane tworzenie formy architektonicznej. Implikuje to potrzebę rozszerzenia zakresu i zmiany standardowego podejścia w analizie konstrukcyjnej.
EN
The paper presents the author’s experience and his personal views on the challenges that arise from the new trend in design – Free Form Design (FFD). Based on the experience gained it was possible to identify the hazards that unfettered creation of architectural form poses for the structural system. This implies the need for extension of range and change of the standard approach in the structural analysis.
EN
The article presents advantages offered by the modal analysis in diagnostics of wood-concrete composite beams. It enables estimating stiffness of a sheared connection between a wooden rib and concrete slab of beam and vertical stiffness of supports if the other mechanical properties of beam are known. The presented considerations are supported by the experimental results obtained for the full scale beam.
15
Content available remote Experimental analysis of picture quality after compression by different methods
EN
In this paper we present experimental results comparing the quality of still Black & White (B/W) images compressed using four methods: JPEG, JPEG2000, EZW and SPIHT. The compression was performed on three pictures with differing levels of detail and density (bit-rates - bpp) using VCDemo software. The quality of the compressed pictures is determined by values of MSE, SNR and PSNR. The values are presented in appropriate tables and diagrams. By comparing the values obtained, we have found the methods that give best results depending on the picture bitrate and level of detail.
PL
W artykule opisano rezultaty eksperymentalnego badania kompresji obrazu czarno/białego przy wykorzystaniu czterech metod: JPEG, JPEG2000, EZW i SPIHT. Kompresję wykonywano na trzech obrazach o różnym poziomie detali i różnej gęstości.
EN
Sandwich panels made of deep-profiled steel facesheet, thick and soft PUR core and thin aluminum facesheet are considered. The structural behavior of the panel in two arrangements is analyzed by the way of real experiments. Three-point bending tests were carried out. The laboratory tests unraveled non-linear characteristics of structural behavior. The local instability of the compressed faces was observed. The real experiments were compared with the results of numerical simulations.
EN
A new portable system for experimental investigation in the process of sheet metal hemming was developed. In the introduction, information was provided about the need to use machine vision systems to solve problems that occur in the process of hemming. Then, a test stand designed for the practical implementation of a three-step hemming process was presented. Among the different vision systems available, a method using laser light scanning for reconstruction of the geometry of the examined hemmed sample was selected. An optical system for studies of the measurement technique and a method of image analysis used in the described example of the plastic forming process were presented. In this process, first, the test sample image is recorded, and it is analysed next to obtain information about an outline of the deformed line. Further in the text, a new method proposed by the author for the reconstruction of a 3D outline of the hemmed sample was disclosed along with a technique to calculate the value of strain on its surface. Finally, a portable measurement system for quality control of the hemmed surface edges was shown for the industrial application.
PL
Nowy, przenośny system doświadczalny został zaproponowany do analizy procesu zawijania. We wstępie przedstawiono informację o potrzebie wykorzystania systemów wizyjnych w analizie problemów występujących w procesie zawijania. Następnie, przedstawiono konstrukcję narzędzi do realizacji trzystopniowego procesy zawijania. Pośród licznych wizyjnych urządzeń pomiarowych stosowanych do pomiarów i rekonstrukcji 3D elementów zawijanych, zaproponowana została przez autora metoda skanowania. W przedstawionym artykule, odniesiono się do problemów zaproponowanych technik pomiarowych i procesu obróbki obrazu w odniesieniu do przykładów doświadczalnych. Po pierwsze, zapisany obraz próbki jest analizowany pod kątem jej geometrii. W dalszej części, przedstawiono szczegóły odnośnie zaproponowanej nowej metody rekonstrukcji geometrii wraz z pomiarem wartości odkształcenia. Na koniec, przedstawiono, system przenośny kontroli jakości w ujęciu przemysłowym.
PL
Płyta warstwowa jest kompozytem o bardzo atrakcyjnych właściwościach – dzięki swojej budowie jest elementem jednocześnie wytrzymałym i lekkim. Idea pozwalająca na osiągniecie tych własności bazuje na współpracy materiałów o różnych parametrach wytrzymałościowych, co prowadzi jednoczenie do pewnych trudności w analizie i projektowaniu. Celem niniejszej pracy jest lepsze poznanie zachowania płyty warstwowej z okładzinami z płyty cementowo-magnezjowej i rdzeniem wykonanym z polistyrenu ekspandowanego poddanej obciążenie statycznemu na drodze badań laboratoryjnych oraz poprzez analizę stworzonego na ich podstawie modelu obliczeniowego. W celu określenia niezbędnych charakterystyk wytrzymałościowych przeprowadzono testy zginania i ściskania materiałów składowych oraz na próbkach kompozytu. Uzyskane wyniki pozwoliły na stworzenie uproszczonego modelu numerycznego metody elementów skończonych w programie komercyjnym. Z jego pomocą przeprowadzono symulację wspomnianych wcześniej badań doświadczalnych i dokonano porównania otrzymanych wyników z wielkościami pomierzonymi eksperymentalnie.
EN
A sandwich panel exemplifies a durable and light-weight composite structure. The idea of constructing a new substance of superior properties by combining materials possessing completely different mechanical characteristics can cause considerable difficulties in a proper modelling and designing. The aim of the present work is to extend the knowledge of the behavior of a composite sandwich panel with an expanded polystyrene foam core placed between two facings made of magnesium oxide boards under static load in a course of experimental analysis and FEM calculation. In order to obtain a comprehensive picture of the mechanical performance of the sandwich structure a set of compressive, shear and flexural tests were performed both for each single component and for the entire structures. The results obtained in experimental tests were used to create a simplified FEM model within the commercial program ABAQUS/CAE. The results of FEM simulations of the compression and flexure tests for a composite sandwich structure were compared with experimental data.
20
Content available remote Numerical and experimental vibration analysis of domestic washing machine drum
EN
The vibration of a drum of the washing machine Samsung WF0804 caused by the unbalanced mass attached to the rotating unit was examined. The motion equations of the washing machine drum were derived. The stand for experimental measurement was presented. The numerical results were compared with experimental measurements. General conclusions were mode. The analysis will make up the basis for experimental studies aimed at finding the most effective way of balancing drum vibrations.
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