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EN
The subject of the study is a sandwich plate-strip subjected to a four-point load. An analytical model of the strip was developed, taking into account the classical zig-zag theory, namely the broken line hypothesis. Three parts of the plate-strip are distinguished: two of them are the edge parts, where bending and the shear effect is considered, the third one is the middle part subjected to pure bending. The total maximum deflection of the plate-strip and the maximum deflection of the selected middle part of the plate-strip are calculated. The FEM-numerical study is carried out similarly to the analytical approach. The experimental study was carried out on the test stand in the Institute of Rail Vehicles TABOR. The analytical, numerical and experimental results are compared each with other. The sandwich panels can be used as parts of the floor or rail vehicle paneling.
PL
Przedmiotem badań jest trójwarstwowe pasmo płytowe poddane czteropunktowemu zginaniu. Opracowano analityczny model tego pasma, korzystając z klasycznej teorii linii łamanej nazywanej teorią Zig-Zag. W paśmie tym wyróżniono trzy przedziały: dwa brzegowe, w których występuje zginanie i ścinanie oraz jeden środkowy, w którym występuje czyste zginanie. Wyznaczono całkowite ugięcie maksymalne pasma płytowego oraz maksymalne ugięcie odcinka środkowego. Przeprowadzono obliczenia numeryczne metodą elementów skończonych (MES) dla takiego samego modelu pasma, jak wyżej wspomniany model analityczny. Próbę doświadczalną przeprowadzono na stanowisku badawczym w Instytucie Pojazdów Szynowych. Porównano wyniki badań analitycznych, numerycznych i doświadczalnych. Analizowane płyty warstwowe mogą być stosowane, m. in. jako części podłogi lub poszycia pojazdu szynowego.
PL
Dokonano przeglądu badań doświadczalnych kształtowników stalowych giętych na zimno. Badania były wykonywane przez Katedrę Konstrukcji Budowlanych Politechniki Rzeszowskiej w ramach umowy przemysłowej nr RB-U-18218 pt. "Wykonanie badań przemysłowych w zakresie profili giętych na zimno, stosowanych w konstrukcjach hangarów lotniczych dla firmy KOBEX".
EN
The article presents a review of experimental tests of cold-formed steel profiles carried out by the Department of Building Structures at the Rzeszów University of Technology under industrial contract No. RB-U-18218 entitled "Pertorming industrial research in the field of cold-formed profiles used in the construction of aircraft hangars for the company KOBEX".
EN
A retaining wall is built to provide support to the soil when there is a change in elevation of the ground. Weep holes present in the retaining wall help water to seep through it. Filter protection should be made behind the weep holes to prevent soil erosion around the weep holes. The classic filter material that is widely used is gravel, which is packed according to Hudson’s law. Laboratory experiments were conducted to understand the seepage function of alternative material such as crumb rubber and geocomposite (fabricated) in a homogenous sand layer and in-situ soil. The time taken by the water to reach the weep holes was calculated and compared. From the results, it is suggested to use crumb rubber as an alternative packing material behind the weep hole.
PL
W pracy przedstawiono wyniki badań doświadczalnych mających na celu określenie wielkości i rozkłady naprężeń własnych w typowych słupach skrzynkowych spawanych z kształtowników profilowanych na zimno. Badania wykonano metodą trepanacyjną, rejestrując zmianę stanu odkształceń po rozcięciu na paski modelu krótkiego słupa. Wyniki badań porównano z rezultatami innych badaczy i mogą one stanowić podstawę do dalszych analiz stateczności ścian słupa skrzynkowego z uwzględnieniem naprężeń własnych.
EN
The paper presents the results of investigations aimed at determining the size and distribution of residual stresses in box columns welded from cold-formed sections. Trepanation method (strip cutting method) is used to determine the change in the state of deformation after cutting into strips of the short column model. The results were compared with the results of other researchers and may form the basis for further analyses of the stability of the walls of the box column, taking into account the natural stresses.
6
Content available remote Wybrane badania symulacyjne i doświadczalne toru bezstykowego
PL
W artykule przedstawiono zagadnienia dotyczące toru bezstykowego oraz omówiono problemy związane z jego eksploatacją. Istotną część artykułu stanowią wyniki badań symulacyjnych wykonanych dla opracowanego modelu toru bezstykowego obciążonego różnymi wartościami sił wzdłużnych, które mogą się pojawić podczas eksploatacji. Siły działają w szynie wskutek pojawienia się naprężeń termicznych o wartościach uzależnionych od zmiany temperatury szyny. Oprócz badań symulacyjnych przedstawiono również koncepcję badań doświadczalnych, które będą wykonywane na wybranym odcinku linii kolejowej. Do pomiaru sił wzdłużnych w różnych warunkach obciążenia i utrzymania toru bezstykowego wykorzystany będzie przyrząd MS-02. Wyniki pomiarów wykonanych w eksploatowanym torze posłużą w dalszej perspektywie do zweryfikowania i dalszego doskonalenia modeli numerycznych.
EN
The article presents issues related to the CWR (continuous welded track) and discusses the problems associated with its operation. An important part of the article is the results of simulation tests carried out for the developed model of a CWR track loaded with various values of longitudinal forces that may occur during operation. The forces act in the rail due to the occurrence of thermal stresses with values depending on the temperature change of the rail. In addition to simulation tests, the concept of experimental tests that will be performed on a selected section of the railway line is also presented. The MS-02 device will be used to measure longitudinal forces under various load conditions and to maintain the contactless path. The results of measurements made in the exploited track will be used in the long term to verify and further improve the numerical models.
PL
Przedstawiono wyniki serii badań elementów stalowych regałów wysokiego składowania w tym: połączenia zaczepowego między słupem a belką nośną, ścinania na zaczepach belek nośnych oraz nośności rygli. Specyfika pracy regałów wysokiego składowania sprawia, że badania są niezbędną częścią procesu projektowania tego rodzaju konstrukcji. Wyniki z badań będą stanowiły podstawę opracowania i walidacji modelu numerycznego.
EN
The article summarizes the results of experimental tests carried out on elements of steel static storage pallet rack system, including: bending tests on beam end connectors, shear tests on beam end connectors and connector locks, bending tests on beams. The specificity of the way pallet racks are constructed and transferring the applied loads makes testing an indispensable part of the design process of this type of structures. Test result will be used to create and validate the numerical model.
EN
This paper presented a systematic approach toward localized failure inspection of internally pressurized laminated ellipsoidal woven composite domes. The domes were made of thin glass fiber reinforced polymer (GFRP) woven composite layups [0,0,0], [0,30,0], [0,45,0], and [0,75,0]. The analytical results demonstrated that the circumferential regions near meridian w = 458 in prolate ellipsoidal domes and near meridian w = 908 in oblate ellipsoidal domes sustain the highest deformation under internal pressure. This observation was then confirmed by the numerical and experimental results. In addition, the numerical and experimental results showed localized rather than uniform failure in those regions, irrespective of changes in laminate stacking sequence. It was observed that localized failure occurs since the woven fibers configuration in some areas of woven remains in initial geometry (square shape), while the rests are deformed into the rhombic shape. In other words, by moving along the circumferential direction from the area close to u = 08 to u = 458 and u = 458 to u = 908, the shape of woven fibers gradually changes from square (strong area) to rhombic (weak area), and rhombic to square, respectively. Thus, to minimize failure pressure, the meridian region vulnerable to failure must initially be identified. Afterwards, the rhombic regions in the circumference corresponding to that meridian must be strengthened.
EN
Soil modification with Portland cement is the most common practice in geotechnical engineering. The application of micro-fine cement causes proper intrusion of the provided slurry into the soil voids and consequently decreases the porosity to a greater quantity. In order to determine the utility and behavior of cements with different blains, non-destructive and destructive tests such as grain-size distribution of cements by laser-ray, sedimentation, permeability and compressive strength were employed. The results of experimental studies and observations demonstrated a suitable mix-design for upper and lower parts of the cement-grading curve that are of prime importance for grouting and stabilization. Meanwhile, by increasing the fineness of the cement, the permeability decreases to a considerable extent and the compressive strength increases. Moreover, the blain content close to 5000 cm2/gr application led to the optimization of the effect of void reduction in a grouted soil mass compared to the lower and higher amount of blain content. The results of various tests indicate that an optimum blain can be used to achieve the designed geotechnical criteria.
10
EN
The purpose of this study is to find and develop a model for measuring global solar irradiation at various angles from 0° to 90°. Through empirical studies, a suitable model for the studied site at Ouled Djellal, Biskra (Algeria) was developed, with preliminary data to be used in thermal simulation software for building and simulation of solar energy systems. The results of the proposed model were compared with the experimental data and there was excellent correlation.
11
Content available remote Experimental study of the flow around two finite square cylinders
EN
An experimental investigation is conducted on the air flow past two wallmounted finite length side-by-side square cylinders, each of the aspect ratio AR = 7. The cylinder center-to-center spacing ratio T/d is varied from 2 to 6, where d is the side-width of the cylinder. The cylinders are placed at three incidence angles with respect to the freestream velocity, i.e. both cylinders at zero incidence angle (case I), both cylinders at 45° incidence angle (case II), and one cylinder at zero incidence angle with the other at 45° incidence angle (case III). The pressure distributions on the surfaces of the cylinders are measured at Reynolds numbers of 5.9 × 104–8.1 × 104. In addition, the flow structures are visualized in a smoke wind tunnel at the Reynolds number of 2 × 103. Depending on the flow characteristics, four flow structures are identified at the mid-height of the cylinders, namely the asymmetric flow, antiphase shedding flow, leading-edge separated flow and wedge flow. The sectional drag near the bottom is more sensitive to T/d than that near the top. The sectional drag coefficient measured at 0.5d below the mid-span can represent the surface-averaged drag coefficient on the entire cylinder.
12
EN
This paper presents an experimental study on structural performance of concrete poles used in electric power distribution network (EPDN). Three full scale 12-m concrete poles were tested; and a numerical study on a 7-span distribution line was also carried out in order to investigate lateral behavior of the network under severe weather conditions, as it is believed EPDN has a vital role on sustainability of power transmission from the power planet to the consumers which might be hundreds kilometers far away. One of the main issues in EPDN is concrete poles’ collapse under simultaneous wind and ice loads in some unreachable snow covered areas. However, the results show that the prescribed loading regimes by standards do not induce any damage into the distribution network nevertheless some unforeseen loads like gust wind load in heavy weather conditions cause the poles’ failure. Therefore, a non-linear pushover analysis was carried out to find out the weakest part of the distribution network; and finally some suggestions for increasing the EPDN's sustainability are made.
EN
Dome curvatures of pressure vessels often sustain highest level of stresses when subjected to various loading conditions. This research is aimed at investigating the effect of dome geometrical shape (hemispherical, torispherical, and ellipsoidal domes) on mechanical deformation and crack length of laminated woven reinforced polymer (GRP) composite pressure vessels under low-velocity impact (LVI) (case one) or combination of LVI and internal pressure (case two). The study is based on finite element (FE) simulations with laboratory-based experimental validation studies. It was observed that the maximum vertical displacements () and crack length along the diameter of deformation (a) are both of lower magnitude in case one. Damage intensity and fracture differ for different combinations of loading. Only matrix breakage and debonding occurs in case one and fiber breakage occurs in case two. The dome geometric shapes used in this study were found to be invariant to both damage intensity and failure modes. Irrespective of the type of load applied, the magnitude of and crack length correlate with dome geometric shape as the maximum and the minimum occur in torispherical and hemispherical domes, respectively. The maximum and the minimum crack lengths also take place in torispherical and hemispherical domes, respectively.
EN
Atmospheric temperature and directed solar radiation have a significant effect on the temperature field of high-speed railway (HSR) concrete bridge and ballastless track structure. However, temperature actions are random process of which distribution laws are difficult to explore, and existing statistical methods for structure temperature analysis are still not precise. So far, there are few researches for annual temperature spectra and design codes for bridge–track system. Based on the one-year observation data, this paper investigated the temperature actions for Chinese HSR bridge–track structure. By utilizing reliability high moment theory, a statistical method which could built virtual distribution was put forward. Based on the renewed study, the effects of waterproof for deck were taken into consideration, a temperature action model was proposed which is suitable for both bridge and track structure. In addition, for track structure, the previous temperature load models were modified. Apart from that, by proposing the concepts of temperature uniform and fluctuant spectra, the research evaluated service performance of structure. Finally, the distribution regularities of uniform temperature spectra were fitted by Fourier series, and the relationship between structural and atmospheric uniform temperature was established (formula (25)). As a result, according to 50 years recorded atmospheric temperature data, the prediction model of the structure extreme temperature was suggested, and by taking the recurrence interval of 100, 150 and 300 years, the extreme temperatures of the system are 52.23, 54.34 and 57.77 °C.
PL
W pracy przedstawiono narzędzia doświadczalne i symulacyjne, które mogą być wykorzystywane w ocenie jakości i trwałości wybranych elementów nawierzchni kolejowej. W artykule zaprezentowano wybrane wyniki badań doświadczalnych naprężeń własnych w procesie produkcji elementów stalowych rozjazdów kolejowych, jak też wyniki badań eksploatacyjnych używanych do oceny konstrukcji nawierzchni. Oprócz badań doświadczalnych zaprezentowane zostały wyniki badań symulacyjnych stanowiących m.in. uzupełnienie badań poligonowych.
EN
The paper presents experimental and simulation instruments that can be used to evaluate the quality and durability of selected the superstructure and its components. The article presents selected results of experimental residual stress tests in the steel production process of railway turnouts as well as the results of operational tests used to evaluate the construction of the pavement. In addition to experimental research, the results of simulations are presented as supplementary training.
PL
W artykule przedstawiono rodzaje, właściwości i metody określania cech mechanicznych zbrojeniowych prętów kompozytowych FRP. Na podstawie analizy wyników badania właściwości wytrzymałościowych prętów z włóknem szklanym GFRP i prętów z włóknem bazaltowym BFRP zaprezentowano metody określania gwarantowanej wytrzymałości na rozciąganie i gwarantowanego modułu sprężystości zbrojenia niemetalicznego według standardów ACI 440.1R oraz CSA-S807. Jako przykład procedury projektowania elementu betonowego zbrojonego prętami FRP omówiono metodę obliczania nośności na zginanie według ACI 440.1R. Do obliczeń wykorzystano wyniki badań właściwości mechanicznych prętów GFRP i BFRP.
EN
The paper presents the sorts, properties and designing methods for structures with FRP bars. The methods to determine the guaranteed tensile strength and guaranteed modulus of elasticity according to the guidelines for non-metallic reinforcement ACI 440.1R and CSA-S807 were presented, based on the analysis of strength parameters test results of GFRP bars and BFRP bars. As an example, the procedure of calculating the flexural capacity of structure reinforced with FRP bars according to ACI 440.1R was discussed. The results of the mechanical properties tests of GFRP bars and BFRP bars were used for calculation.
EN
The subject of the study was aluminum samples of varying thickness. The aim of the study was to perform the experimental stamping process of the samples on a universal testing machine and a numerical analysis on two independent computer systems Abaqus® and Deform-3D. As part of the numerical analysis, bilinear material model was included, taking into account elastic and plastic characteristics. The study was conducted in a dynamic environment with geometric nonlinearity. The results obtained from experimental research were confronted with those obtained by FEM computer simulation. During the research, numerical model of the stamping process has been developed, which was validated with the results of experimental research.
EN
The paper presents the experimental investigation carried out in order to identify bearing dynamic coefficients of two hydrodynamic bearings from impulse responses. In this method the stiffness, damping and mass coefficients of two hydrodynamic bearings were calculated in a single algorithm. For each rotational speed, were obtained 12 dynamic coefficients which enable to fully describe the dynamic state of the rotor. Exciting force signals, applied using an impact hammer were shown. Displacements of the shaft were measured by eddy current sensors. The measurements were carried out at various rotational speeds, including resonance speeds. The vibration amplitude in a resonance case increases significantly with time after the excitation was induced by an impact hammer. Excitations of the rotor with an impact hammer were recorded using a high-speed camera. These unique recordings and simultaneous analysis of the trajectory of the bearing journals depict the contact phenomena that occur during impulse excitation of the rotor.
PL
Przedstawiono wybrane wyniki badań doświadczalnych i teoretycznych dotyczących obciążeń konstrukcji budowlanych cyklicznym zamarzaniem/rozmarzaniem wody, oddziaływaniem wysokiej temperatury w warunkach pożarowych i krystalizacją soli. Przedstawiono także model matematyczny sprzężonych zjawisk cieplno-wilgotnościowych i degradacji w porowatych materiałach budowlanych, zawierających wodę i sole w niej rozpuszczone, z uwzględnieniem przemian fazowych: woda – lód i sól rozpuszczona – sól krystaliczna. Opracowano program komputerowy HMTRA/COMES, który zastosowano do analizy procesów degradacji materiałów budowlanych.
EN
In this article some results of experimental and theoretical research, concerning three types of environmental loads on building structures, i.e.: cyclic freezing/thawing of water, effect of high temperature at fire conditions, and salt crystallization. There was presented mathematical model of coupled hygro-thermal phenomena and deterioration in a porous building materials containing water and dissolved salt, considering phase changes: water – ice and dissolved salt – crystallized salt. The computer code HMTRA/COMES was developed and used for the analysis of building material degradation processes.
PL
Przedstawiono koncepcję wzmocnienia słupów murowych za pomocą taśm z kompozytów włóknistych, naklejanych przy użyciu żywic epoksydowych. Podano wyniki wstępnych badań doświadczalnych dotyczące mechanizmu niszczenia wzmacnianych słupów.
EN
The method of strengthening of masonry columns by FRP stripes glued with use of epoxy resin was shown in the paper. Results of preliminary experimental tests applied to behaviour of failure of strengthened columns were presented.
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