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Tytuł:
Analiza zjawiska odspajania katodowego powłoki na podstawie badań terenowych oraz badań laboratoryjnych
Cathodic disbondment of coating on the basis of field and laboratory tests – phenomenon analysis
Autorzy:
Stochaj, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/1835083.pdf
Data publikacji:
2019
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
potencjał
odspojenie katodowe
badania terenowe
badania laboratoryjne
potential
cathodic disbondment
field tests
laboratory tests
Opis:
W artykule omówiono wyniki uzyskane podczas badań laboratoryjnych i terenowych zjawiska odspajania katodowego powłoki pod wpływem nadmiernej polaryzacji katodowej. Zjawisko to podczas nadmiernej polaryzacji gazociągów może być przyczyną naruszenia integralności gazociągu. W wyniku odspajania powłoki w miejscu defektu pod powierzchnię powłokową dostaje się elektrolit, który w wyniku niekorzystnego nadmiernego oddziaływania ochrony katodowej w miejscu defektu powłoki ułatwia dalsze niekontrolowane jej odspajanie. Prąd ochrony katodowej w wyniku powiększania się powierzchni defektu pod powłoką ma utrudniony dostęp, przez co w miejscu defektu nie może być zapewniona skuteczna ochrona. Do badań wybrano 6 powłok wytwarzanych w kraju, które najczęściej stosuje się w czasie eksploatacji w różnych warunkach terenowych. W celu przeprowadzenia badań na terenie Instytutu Nafty i Gazu wykonano stanowisko terenowe, na którym zainstalowano 42 próbki do badań, które podłączono do instalacji ochrony katodowej. Do wykonania badań laboratoryjnych zaprojektowano i wykonano stanowisko, które wyposażono w odpowiedni sprzęt badawczy. Opracowano harmonogram badań, który obejmował przeprowadzenie badań w czasie 24 miesięcy w latach 2016 do 2018. Podczas badań na stanowisku terenowym i laboratoryjnym regularnie kontrolowano parametry polaryzacji. W czasie 24 miesięcy badań zgodnie z harmonogramem próbki do badań były wyciągane z ziemi i poddawane szczegółowym oględzinom. Następnie próbki badano na wielkość odspojenia katodowego, a uzyskane wyniki badań wstępnie analizowano i archiwizowano. Uzyskane wyniki badań laboratoryjnych porównano z wynikami badań terenowych. Przedstawiono analizę i omówiono otrzymane wyniki badań. Z analizy wyników badań wyciągnięto wnioski. W artykule zawarto wniosek, że zjawisko odspajania katodowego jest silnie związane z rodzajem powłoki oraz jakością przygotowania powierzchni stalowej rury przed nałożeniem powłoki.
The article discusses the results of tests obtained during laboratory and field tests of cathodic disbondment under the influence of excessive cathodic polarization. This phenomenon, during over-polarization of gas pipelines, may be a reason to breach the integrity of the gas pipeline. As a result of disbondment of the coating in the place of the defect, an electrolyte gets underneath the surface of the coating, which due to the unfavorable excessive influence of cathodic protection in the place of the defect of the coating facilitates further uncontrolled detachment. The cathodic protection current, as a result of the enlargement of the defect surface under the coating, has difficult access, which means that its effective protection cannot be ensured in the place of the defect. Six coatings manufactured in the country were selected for the tests, which are most often used during operation in various field conditions. In order to carry out the tests, a field station was made on which 42 test samples were installed, which were connected to the cathodic protection installation. A station was designed and constructed to perform laboratory tests, which were equipped with appropriate research equipment. A research schedule was prepared, which included testing within 24 months in 2016 to 2018. During field and laboratory tests, polarization parameters were regularly monitored. The obtained results of laboratory tests were compared with the results of field tests. During the 24 months of testing according to the schedule, the test samples were taken out of the ground and subjected for detailed inspection. The samples were then tested for cathodic disbondment, and the obtained test results were initially analyzed and archived. The obtained results of laboratory tests were compared with the results of field tests. The analysis was presented and the obtained test results were discussed. The analysis of the research results drew conclusions. The paper concludes that the phenomenon of cathodic disbondment is strongly associated with the type of coating and the quality of surface preparation of the steel pipe before applying the coating.
Źródło:
Nafta-Gaz; 2019, 75, 8; 482-488
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of notch depth on CTOD values in fracture tests of structural steel elements
Autorzy:
Kowalski, J.
Kozak, J.
Powiązania:
https://bibliotekanauki.pl/articles/258854.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
brittle fracture
CTOD
numerical modelling
laboratory tests
Opis:
In elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climate, the certifying institutions more and more often require Crack Tip Opening Displacement (CTOD) tests instead of conventional impact tests, especially for steel and welded joints of more than 40 mm in thickness in the case of high-strength steel, and more than 50 mm for the remaining steels. The geometry of specimens and the test procedure are standardised; however, these standards provide some margin for specimen notch depth. The paper analyses the effect of notch depth difference, within the range permitted by the standards, on the recorded CTOD values of a given material. The analysis was performed via numerical modelling of destruction of specimens with different notch geometries and further verification of the obtained numerical results in laboratory tests. The calculations were carried out at the Academic Computer Centre in Gdansk.
Źródło:
Polish Maritime Research; 2018, 2; 85-91
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Fatigue Tests Of Landing Gears
Autorzy:
Skorupka, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/2105139.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
fatigue
landing gears
laboratory tests
dynamic testing
Opis:
Landing gears are one of the main components of an aircraft. The landing gear is used not only during take-off and landing but also, in most cases, during ground manoeuvres. Due to its function, the landing gear is also one of the key safety components of the aircraft due to dissipating landing loads acting on the aircraft. The mentioned loads come from both the vertical and horizontal speeds during touchdown and by the aircraft’s losing the speed by braking. The landing gear is then loaded with constantly changing forces acting in various directions during every landing, with the only difference coming from their magnitude. The repeatable loading conditions cause significant wear of the landing gear. This wear can be divided into two categories, one is the wear of consumable parts such as the brake linings and the other is the fatigue wear of the structural components. The latter type of wear is much more dangerous due to its slow, and in many cases, unnoticeable progression. Fatigue wear can be estimated by numerical analyses - this method works with a great degree of probability on single components but due to the complexity of the landing gear as a whole it is not precise enough to be applied to the full structure. In order to evaluate the fatigue of the whole landing gear the best method accepted by regulations is the laboratory testing method. It involves a series of various drop tests resembling the real landing condition distribution. The aim of the tests is to check the fatigue wear of the landing gear and to prove its reliability for certification and/or operational purposes. In this paper the author describes the basics of the landing gear fatigue wear, possibilities of its evaluation and presents laboratory dynamic method used for extensive tests in life-like operation conditions.
Źródło:
Fatigue of Aircraft Structures; 2020, 12; 69--77
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tests and selection methodology for brake linings friction material
Autorzy:
Grygorcewicz, P.
Tywoniuk, A.
Powiązania:
https://bibliotekanauki.pl/articles/245139.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
brakes
brake linings
friction material
laboratory tests
Opis:
This article presents selected issues related to the selection methodology of the brake linings during the research process. It is a very important issue due to effect on the vehicle safety. Safety concerns are applicable to both road/track vehicles and aircraft. Scientific institutions and research centers make continuous efforts in order to improve brake lining materials and full-scale brakes. Analytical prediction of the friction material properties and behavior is not accurate enough due to complexity of the physical phenomena. Analysis of the friction materials is difficult due to scarce of data given by the manufacturers. Every friction material needs to be tested in order to prove its properties. First stage of the selection is the tests made in laboratory using both model and full-scale techniques. Because of the laboratory tests, following parameters are obtained: weight and geometrical brake wear, braking torque, friction coefficient and brake temperature. All of these factors must be taken into account for linings selection and design a prototype of the brake. Selection of the friction material can be performed in consideration of various requirements of the brake system users and law defined factors. Authors of the paper base on the extensive experience of the Institute of Aviation, Landing Gear Laboratory tests of brake linings.
Źródło:
Journal of KONES; 2014, 21, 1; 91-97
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tests of loading efficiency of worm-type cutting drums in longitudinally inclined longwall working
Autorzy:
Wydro, T.
Powiązania:
https://bibliotekanauki.pl/articles/111202.pdf
Data publikacji:
2018
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
laboratory tests
spoil loading
worm-type cutting drums
Opis:
This article presents the execution and results of tests of the loading efficiency of wormtype cutting drums as a function of the slope of a longwall working. The tests were carried out at various angles of longitudinal inclination of a longwall within a range of 0 degrees to 9 degrees along the strike. In real conditions, the separation of the two basic processes that take place during operation of a longwall shearer (i.e., milling and loading) is not possible; therefore, the research was carried out under laboratory conditions at the Department of Mining, Dressing, and Transport Machines at AGH University of Science and Technology in Krakow. The tests were carried out on a special station that allowed for the gradual change of the longitudinal and transverse slope of a longwall working. Based on the conducted tests, it was found that the inclination of a longwall working influences the loading efficiency; i.e., that, along with an increase in the angle of the longitudinal inclination, loading resistance increases while the loading efficiency decreases.
Źródło:
Mining – Informatics, Automation and Electrical Engineering; 2018, 56, 4; 65-73
2450-7326
2449-6421
Pojawia się w:
Mining – Informatics, Automation and Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Examples of the mass movement investigations in different types of deposits
Autorzy:
Bednarczyk, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1182856.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
osuwiska
techniki monitoringu
geotechnika inżynierska
testy
in situ
testy laboratoryjne
landslides
monitoring techniques
geotechnical engineering
in situ tests
laboratory tests
Opis:
W artykule przedstawiono przykłady geotechnicznych i geośrodowiskowych badań powierzchniowych ruchów masowych. Badania z zastosowaniem technik monitoringu obszarów osuwiskowych obejmowały zarówno badania in situ, jak i testy laboratoryjne. Przedstawione projekty obejmowały wybrane rodzaje testów w różnych utworach. Stosowano konwencjonalne wiercenia i pobieranie próbek, a także profilowania GPR, GPS i CPTU oraz monitoring inklinometryczny i piezometryczny. Wyniki testów terenowych porównano z badaniami laboratoryjnymi, takimi jak badania podstawowych właściwości fizycznych gruntów, pomiary edometryczne, badania w aparacie bezpośredniego ścinania, badania wytrzymałości na jednoosiowe ściskanie oraz badania trójosiowe. Niniejszy artykuł oparto na badaniach karpackich osadów fliszowych, wykonywanych dla polskiej administracji drogowej (finansowanych przez Europejski Bank Inwestycyjny), w ramach projektu "Osłona przeciwosuwiskowa", które nadal są kontynuowane. Przedstawiono również przykłady osuwisk występujących w polskich kopalniach odkrywkowych. Opisano także badania iłów polskich i norweskich, przeprowadzonych w ramach projektu finansowanego przez Norweską Radę Badań Naukowych i NATO, a także zaprezentowano wyniki wybranych projektów zabezpieczenia osuwisk oraz wyniki obliczeń stabilności zboczy.
Źródło:
Polish Geological Institute Special Papers; 2005, 20; 14--16
1507-9791
Pojawia się w:
Polish Geological Institute Special Papers
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oddziaływanie zasolonych wód kopalnianych na mechaniczne właściwości skał w kopalniach rud miedzi
Impact of mine brines on mechanical properties of rocks in copper mines
Autorzy:
Kijewski, P.
Lis, J.
Powiązania:
https://bibliotekanauki.pl/articles/350337.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
właściwości geomechaniczne
badania laboratoryjne
geomechanical properties
laboratory tests
Opis:
W obszarze złoża rud miedzi występują bardzo zróżnicowane warunki prowadzenia robót górniczych wynikające z właściwości masywu skalnego. Nowym zjawiskiem jest obecność wód zasolonych o stężeniu wzrastającym wraz z głębokością zalegania złoża. W artykule przedstawiono wyniki badań nad wpływem zmineralizowanych wód kopalnianych na podstawowe właściwości wytrzymałościowe i odkształceniowe wybranych odmian piaskowców i skał węlanowych.
There are different mining conditions resulting from the properties of rock-mass in the copper deposit. The new feature is the presence of brines with salt content increasing with the depth of ore. The paper presents the results of investigations on the impact of mine brines on basic strength and properties of select varieties of sandstones and carbonate rocks.
Źródło:
Górnictwo i Geoinżynieria; 2009, 33, 1; 333-343
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast, non-destructive measurement of roof-bolt loads
Autorzy:
Skrzypkowski, Krzysztof
Korzeniowski, Waldemar
Zagórski, Krzysztof
Dominik, Ireneusz
Lalik, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/178690.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
expansion-shell bolt
monitoring
non-destructive method
laboratory tests
Opis:
This paper discusses the pull-out laboratory tests and the monitoring of expansion-shell bolts with a length of 1.82 m. The bolts comprised the KE-3W expansion shell, a rod with a diameter of 0.0183 m and a profiled, circular plate with a diameter of 0.14 m, and a gauge of 0.006 m. The bolts were installed in a concrete block with a compressive strength of 75 MPa. The tests were conducted on a state-of-the-art test stand owned by the Department of Underground Mining of the AGH University of Science and Technology. The test stand can be used to test roof bolts on a geometric scale of 1:1 under static and rapidly varying loads. Also, the stand is suitable for testing rods measuring 5.5 m in length. The stand has a special feature of providing the ongoing monitoring of bolt load, displacement and deformation. The primary aim of the study was to compare the results recorded by two different measurement systems with the innovative Self-Excited Acoustic System (SAS) for measuring stress variations in roof bolts. In order to use the SAS, a special handle equipped with an accelerometer and exciter mounted to the nut or the upset end of the rod was designed at the Faculties of Mining and Geoengineering and Mechanical Engineering and Robotics of the AGH University of Science and Technology. The SAS can be used for non-destructive evaluation of performance of bolts around mining workings and in tunnels. Through laboratory calibration tests, roof bolt loads can be assessed using the in-situ non-destructive method.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 2; 93-101
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena przydatności wybranych testów in situ i badań laboratoryjnych dla identyfikacji i przeciwdziałania procesom geodynamicznym
In situ and laboratory tests valuation for recognition and counteraction in geodynamic processes
Autorzy:
Bednarczyk, Z.
Powiązania:
https://bibliotekanauki.pl/articles/349156.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
osuwiska
testy in situ
badania laboratoryjne
analiza stateczności
stabilizacja osuwisk
landslides
in situ tests
laboratory tests
slope stability analysis
landslide counteractions
Opis:
W artykule przedstawiono doświadczenia związane z wykorzystaniem różnorodnych metod badań in situ i laboratoryjnych dla określenia zasięgu, poznania genezy oraz możliwości przeciwdziałania procesom geodynamicznym. Omówiono wykorzystane przez autora metody badań, monitoringu oraz modelowania zachowania osuwisk na podstawie prac w kopalniach odkrywkowych węgla brunatnego, badań wykonywanych w Norwegii oraz w Karpatach fliszowych.
Experience connected with usage of different in-situ and laboratory test is described in the paper. It includes recognition of genesis and possibilities in geodynamic processes counteraction. Chosen by the author methods of landslide research, monitoring and modeling in open-cast mines, Norway and flysch Carpathians are presented.
Źródło:
Górnictwo i Geoinżynieria; 2007, 31, 3/1; 65-79
1732-6702
Pojawia się w:
Górnictwo i Geoinżynieria
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory tests on e-pellets effectiveness for ore tracking
Autorzy:
Błażej, R.
Kawalec, W.
Konieczna, M.
Król, R.
Powiązania:
https://bibliotekanauki.pl/articles/88970.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
RFID tag
ore tracking
DISIRE
laboratory tests
belt conveyor
traceability
Opis:
Assigning transported material with a supplementary information is becoming relevant for the needs of improving the efficiency of industrial processes. In the mining industry annotating the mined ore could bring benefits due to expected decrease of the processing energy consumption and increase of productivity. DISIRE project was focused on the implementation of e-pellets for various raw material processing and transportation processes. The paper presents laboratory tests of altern ative RFID equipment for annotating ore with marked tags. Several aspects of tags traceability were investigated for the needs of the industrial tests that were eventually done in the underground mine environment. The laboratory tests results were compared with the similar tests described in the literature, that were done in the different conditions.
Źródło:
Mining Science; 2018, 25; 7-17
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Haematological changes and metabolic alterations in SARS-CoV-2 infected patients hospitalised at an Infectious Diseases Center, Ibadan, Nigeria
Autorzy:
Alonge, Oluwagbenga
Arinola, Ganiyu
Powiązania:
https://bibliotekanauki.pl/articles/2183414.pdf
Data publikacji:
2022-12-30
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
COVID-19
laboratory tests
reference interval
repurposed drugs
therapeutic action
Opis:
Introduction and aim. Following the use of repurposing drugs to successfully manage coronavirus disease 2019 (COVID-19) patients in an Infectious Diseases Center (IDC) in Nigeria, it was imperative to assess haematological changes and metabolic alterations in these patients which may inform recommendations for future use. Material and methods. Blood samples of admitted COVID-19 Nigerian patients during therapeutic management were analysed for haematological- (total white blood cells (WBC), lymphocyte, monocyte, neutrophil, eosinophil, basophil and neutrophil:lymphocyte ratio) and blood chemistry- parameters [total protein, total and conjugated bilirubin, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine transaminase (ALT), gamma-glutamyl transferase (GGT), albumin, urea, creatinine, total cholesterol, triglycerides, low-density lipoprotein (LDL), high-density lipoprotein (HDL), PO₄³⁻, Ca²⁺, uric acid, Na⁺, K⁺, Cl⁻ and HCO₃⁻] using autoanalysers. The percentages of patients having values below, within and above reference ranges were compared using Chi-square test while the mean values at admission were compared with mean values at discharge using Student t-test. Results. The mean values of total protein, albumin, Na⁺, HCO₃⁻, uric acid, Ca²⁺, WBC, platelets, lymphocytes, eosinophils and basophils were significantly increased in COVID-19 patients at discharge compared with COVID-19 patients at admission. Also, more percentages of COVID-19 patients at discharge compared with COVID-19 patients at admission had albumin, ALP, total bilirubin, HDL, Na⁺, K⁺, Cl⁻, HCO₃⁻, urea, creatinine, WBC, lymphocytes, neutrophils, monocytes, eosinophils and basophils within normal reference intervals. Conclusion. This study showed that most metabolic and haematological derangements were normalised by repurposing drugs in most of the COVID-19 patients at this IDC, thus supporting the continuous use of this therapeutic option.
Źródło:
European Journal of Clinical and Experimental Medicine; 2022, 4; 383-390
2544-2406
2544-1361
Pojawia się w:
European Journal of Clinical and Experimental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Laboratory tests and analysis of CIPP epoxy resin internal liners used in pipelines – part II: comparative analysis with the use of the FEM and engineering algorithms
Autorzy:
Abel, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/1845155.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
no-dig technologies
laboratory tests
close-fit lining
sewer rehabilitation
Opis:
In the case of underground network infrastructure it can be seen that objects functioning in the second technical condition, according to DWA-ATV 143-2, and subjected to rehabilitation with the use of close-fit trenchless technologies are capable of withstanding external loads. The main external load that is taken into account in engineering calculations in the case of conduits in the second technical condition is external groundwater pressure. In order to compare design parameters obtained with the use of various calculation methods, a comparative analysis was conducted in order to determine the values of critical pressure. The calculations were carried out using popular engineering algorithms. In addition, analyses using the Finite Element Method and Abaqus software as a computational tool were carried out for the purpose of verifying laboratory tests. This paper aims to broaden knowledge concerning the possibility of performing control numerical analyses for close-fit liners installed in pipelines that are in the second technical condition according to DWA-ATV 143-2. The analyses were carried out on ten 3D models. The models were parameterized in order to reflect the CIPP samples in the most accurate way. The computational models were built based on assumptions, which are commonly used in this type of scientific analysis, regarding material parameters and their interactions. The direct value of the performed engineering calculations and numerical analyses is the extension of knowledge in the field of strength parameters that are obtained by various material groups of close-fit liners. Comparative analysis of the results of laboratory tests and numerical analyses, and the conclusions that result from them, constitute the basis for the optimization of the design process and the individual approach to issues related to the use of liners that strengthen underground pipelines.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 3; 307-322
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lift Force Measurement in Landing Gears Dynamic Tests
Autorzy:
Skorupka, Zbigniew
Powiązania:
https://bibliotekanauki.pl/articles/2105196.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
fatigue
Landing Gears
laboratory tests
dynamic testing
lift force measurement
Opis:
As one of the key components of the aircraft in terms of both operation and safety landing gears are of special interest of the aviation regulations. During the touch down landing gears need to dissipate as much of the energy as possible maintaining the lowest volume and weight as required by the aviation design restrictions. According to the aviation regulations landing gears have to be tested in order to prove the dissipation of the calculated landing energy and to evaluate actual loads acting on the fuselage via the mounting nodes of the landing gears. The tests need to replicate the real landing conditions as closely as possible - including the lift force (or lift) acting on the aircraft during landing. The lift force during landing is not sufficient to maintain the aircraft in flight but acts as the relief force to the aircraft weight resulting in lowering loads applied to the fuselage and decreasing landing energy needed to be dissipated. The lift force or lift has to be taken into account during laboratory tests of landing gears. The lift force needs to be simulated in all of the landing gears dynamic tests: performance optimization, proof of the operation for the certification, and the fatigue evaluation. There are two main methods of applying the lift during the tests: equivalent/effective mass or direct lift application. The latter is used at the Landing Gear Laboratory of the Lukasiewicz Research Network - Institute of Aviation (where author works on daily basis). The lift is applied by the pneumatic cylinders built in the test stand. Until recently the control of the lift force value was performed indirectly by the measurement of the pressure inside the pneumatic system. Recently the experimental direct measurement system using force transducers was introduced in order to directly measure the lift force during every test. In the presented paper, the author gives an overview of the lift force measurement system including its design and the results of the preliminary use evaluation.
Źródło:
Fatigue of Aircraft Structures; 2021, 13; 8--16
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of steel and polypropylene fibers addition on selected properties of fine-grained concrete
Wpływ dodatku włókien stalowych i polipropylenowych na wybrane właściwości betonu drobnoziarnistego
Autorzy:
Denisiewicz, A.
Socha, T.
Kula, K.
Pasula, A.
Powiązania:
https://bibliotekanauki.pl/articles/395771.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fibers
fine-grained concrete
laboratory tests
włókna
beton drobnoziarnisty
badania laboratoryjne
Opis:
The article presents results of laboratory tests of selected mechanical and physical properties of fine-grained fiber concrete. Tests were conducted on samples with a different degree of reinforcement made on the basis of steel and polypropylene fibers. For the designed concrete mixtures and prepared samples, slump class, shrinkage, compressive and bending strength and water tightness were determined.
W artykule zaprezentowano wyniki badań laboratoryjnych wybranych właściwości mechanicznych i fizycznych fibrobetonów drobnoziarnistych. Badania przeprowadzono na próbkach o różnym stopniu zbrojenia wykonanych na bazie włókien stalowych oraz polipropylenowych. Dla zaprojektowanych mieszanek betonowych oraz wykonanych próbek wyznaczono klasę konsystencji, skurcz, wytrzymałość na ściskanie i zginanie oraz wodoszczelność.
Źródło:
Civil and Environmental Engineering Reports; 2018, No. 28(4); 138-148
2080-5187
2450-8594
Pojawia się w:
Civil and Environmental Engineering Reports
Dostawca treści:
Biblioteka Nauki
Artykuł

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