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    Wyświetlanie 1-10 z 10
    Tytuł:
    Damage Analysis of the Blade to the Rotor Hub Connection in the Wind Turbine
    Autorzy:
    Gremza, G.
    Zamorowski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/104789.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Rzeszowska im. Ignacego Łukasiewicza. Oficyna Wydawnicza
    Tematy:
    undersized bolts
    mechanical properties
    bolts
    wind turbine
    blade failures
    model of joint
    Opis:
    The paper analyzes possible causes of bolts fracture in the connection of the blade to the hub of the wind turbine rotor. This failure has been growth shortly after the wind turbine was started, a few days after the storm. During the storm, electric power was turned off in the whole surrounding area for many hours, therefore it was impossible to control the device. After an initial analysis of failure modes in other wind turbines, it was found, that the bolts failure in the analysed case may be regarded as quite rare. Due to the fact that a significant part of bolts was broken brittle (flat fracture surfaces and lack of permanent elongation), it was decided to analyse the structure of the material in the direction of stress corrosion and hydrogen embrittlement. Among others, microscope analysis of fracture surfaces after their proper cleaning from corrosion products was carried out. The broken bolts were made as undersized, what is mainly used in fasteners intended for hot-dip galvanizing. On the basis of the purchase documentation analysis, it was presumed that the bolts were not galvanized by their manufacturer, which is obliged to perform the routine inspection in production process preventing the introduction of the hydrogenated bolts into the market. Besides the bolts examination, the scenarios of connection loads in extreme situations, in particular the impact of wind with high energy in the most unfavourable direction relative to the blade and nacelle, as well as the force resulting from the impact of the rotating blade on the tower that preceded the collapse of the whole structure, were considered. Conclusions from the performed tests and calculations by use of two calculation models of the connection were presented.
    Źródło:
    Czasopismo Inżynierii Lądowej, Środowiska i Architektury; 2018, 65, 2; 55-67
    2300-5130
    2300-8903
    Pojawia się w:
    Czasopismo Inżynierii Lądowej, Środowiska i Architektury
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An Impact of Assembly Interference on Stresses in the Die Tool System During Bolt Forging
    Autorzy:
    Nowotyńska, I.
    Kut, S.
    Osetek, M.
    Powiązania:
    https://bibliotekanauki.pl/articles/353903.pdf
    Data publikacji:
    2019
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    forging
    modelling
    simulation
    bolts
    stress analysis
    Opis:
    The article presents an analysis of stresses in the current tool system of the die during the implementation of the third forging operation of the screw M12 class 10.9 with cylinder head and hexagonal socket. It was assumed that the level of negative cracking due to stress can be reduced by using a mounting interference between the die and the tube blank. Due to the design of the tool system value of the die, the interference value cannot be too large. Therefore, an analysis of the influence of the interference between the die and the tube blank in a die tool system on the value and distribution of stresses in the individual components. An analysis of the assembly stresses and the stresses occurring during the process of deformation of the shaped head of the screw was done. The calculations were performed using a commercial software package MARC / Mentat.
    Źródło:
    Archives of Metallurgy and Materials; 2019, 64, 4; 1471-1478
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Fibrous Structure of the Bolt and Its Effect on the Joint Reliability
    Autorzy:
    Dubiel, Tomasz
    Balawender, Tadeusz
    Osetek, Mirosław
    Powiązania:
    https://bibliotekanauki.pl/articles/2049126.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cold forging
    bolts
    fasteners
    grain flow pattern
    Opis:
    The use of cold forging is a widely used solution in many industries. One application is the manufacture of bolts and fasteners. The largest amounts of bolts are used in the automotive and machine industry. Those customers demand high standards of quality and reliability from producers based on ISO 9001 and IATF 16949. Also, the construction, agriculture and furniture industries are raising their expectations for deliveries from year to year. Automotive companies issue their standards specifying specific requirements for products. One of these standards is the aviation standard SAE USCAR 8-4; 2019, which speaks of a compatible arrangement of fibers in the bolt head and in the area of transition into the mandrel. The article presents the cold forging process of flange bolts. Obtaining a compatible, acceptable and incompatible grain flow pattern based of the above mantioned standard was presented. Then the results of FEM simulation were correlated with the performed experiment. The effect of incompatible grain flow system was discussed and presented as the crack initiating factor due to delta ferrite, hydrogen embrittlement, tempering embrittlement. The reliability of the connections was confirmed in the assembly test for yield stress on a schatz machine. The advantages of this method and the difference compared to the tensile test were presented.
    Źródło:
    Archives of Metallurgy and Materials; 2021, 66, 4; 1075-1085
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The Phenomenon of Hydrogen Embrittlement in High-Strength Bolts
    Autorzy:
    Dubiel, Tomasz
    Balawender, Tadeusz
    Osetek, Mirosław
    Powiązania:
    https://bibliotekanauki.pl/articles/2203713.pdf
    Data publikacji:
    2023
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    cold forging
    hydrogen embrittlement
    high-strength bolts
    Opis:
    The hydrogen embrittlement of metals is caused by the penetration and accumulation of hydrogen atoms inside the metal. The failure of the product due to hydrogen embrittlement is delayed in time and does not occur immediately after its manufacture, but several hours, days, or even weeks later. Therefore, the chances of detecting hydrogen embrittlement when checking the quality of the finished product are very slim. The use of high-strength bolts in industry is associated with the risk of hydrogen embrittlement. This phenomenon poses a threat to the safe use of devices by limiting or completely losing the functionality of the bolt joint. Even a low influence of moisture can trigger failure mechanisms. The article proposes a method for assessing the risk of hydrogen embrittlement for high-strength bolts in class12.9. For this purpose, bolts made of material grade 32CrB4 were prepared and in a controlled manner the grain flow inconsistency was made, leading in extreme cases to the production of the forging lap. To perform the study, the device proposed by the European Assessment Document (EAD) was adapted to the testing of hydrogen embrittlement of threaded fasteners in concrete. The concrete substrate was replaced with metal spacers that were preloaded with a bolt. The use of the wedge distance under the bolt head led to the generation of two stress states - tensile and compressive, which translated into an increased risk of hydrogen embrittlement. After being tested, the bolts were visually and microscopically inspected to assess potential locations for cracks and hydrogen propagation. As a result of the conducted tests, it was found that the prepared test method allows to assess the resistance or susceptibility of the bolt to threats related to hydrogen embrittlement.
    Źródło:
    Archives of Metallurgy and Materials; 2023, 68, 1; 395--402
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamic load analysis of the connecting bolts in a universal joint
    Autorzy:
    An, Yuchen
    Liu, Jing
    Li, Zengguang
    Powiązania:
    https://bibliotekanauki.pl/articles/2087028.pdf
    Data publikacji:
    2022
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    dynamic loads
    connecting bolts
    universal joint
    dynamic model
    Opis:
    Dynamic loads of the connecting bolts in a universal joint can greatly affect the bolt fatigue and fracture, as well as the machinery safety and stability. But few researches focused on those. To obtain the dynamic load characteristics of the connecting bolts in a universal joint, this paper established a flexible dynamic model for the connecting bolts. A multibody dynamic model of a universal joint is developed. The dynamic loads on the connecting bolts of the universal joint are analyzed. The influences of the preloads, speeds and loads are studied. The amplitude and frequency properities are obtained. The effect of the preload is small when the preload is in the range of 80%~120% of the standard value. The load and speed have great influence on the time- and frequency-domain dynamic loads of the bolts. The flexible dynamic model of the connecting bolt is closer to the actual situation than the rigid model since it can consider the preload and deformation of the bolts. This study can provide guidance for the fatigue life prediction of the universal shaft and its bolts.
    Źródło:
    Eksploatacja i Niezawodność; 2022, 24, 2; 211--225
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improvement of fatigue life of riveted joints in helicopter airframes
    Autorzy:
    Rośkowicz, Marek
    Godzimirski, Jan
    Jasztal, Michał
    Gąsior, Jarosław
    Powiązania:
    https://bibliotekanauki.pl/articles/1841763.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    riveted joints
    hybrid joint
    fatigue life
    titanium driven blind bolts with pin
    ordinary mushroom head rivets
    Opis:
    Using original cold-formed rivets in repairs of airframes of helicopters is difficult due to no access to inside parts of the airframe. Thus, the main aim of the study was to investigate the possibility to use the blind rivets or hybrid joints by verification the fatigue performance of such joints that must be better than with original rivets. Riveted and hybrid joints have been experimentally tested under static and fatigue loads. Furthermore, numerical calculations of stress distribution for strapped joint have been conducted. The test results covered fatigue life of lap joints and models of repaired airframe sheets using ordinary mushroom head rivets ref. 3558A-4-10, titanium driven blind bolts with pin, ref. MBF2110AB-05-150 and modified hybrid joints. Using titanium driven blind bolts with pin instead of ordinary hammer-bucked rivets, can improve the fatigue life of element made of aluminum alloy AW 2024T3. There are advantages of replacing riveted joints with modified hybrid (rivet & adhesive) joints in threefold increase in fatigue life of repaired airframe structures.
    Źródło:
    Eksploatacja i Niezawodność; 2021, 23, 1; 165-175
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Improvement of fatigue life of riveted joints in helicopter airframes
    Autorzy:
    Rośkowicz, Marek
    Godzimirski, Jan
    Jasztal, Michał
    Gąsior, Jarosław
    Powiązania:
    https://bibliotekanauki.pl/articles/1841792.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
    Tematy:
    riveted joints
    hybrid joint
    fatigue life
    titanium driven blind bolts with pin
    ordinary mushroom head rivets
    Opis:
    Using original cold-formed rivets in repairs of airframes of helicopters is difficult due to no access to inside parts of the airframe. Thus, the main aim of the study was to investigate the possibility to use the blind rivets or hybrid joints by verification the fatigue performance of such joints that must be better than with original rivets. Riveted and hybrid joints have been experimentally tested under static and fatigue loads. Furthermore, numerical calculations of stress distribution for strapped joint have been conducted. The test results covered fatigue life of lap joints and models of repaired airframe sheets using ordinary mushroom head rivets ref. 3558A-4-10, titanium driven blind bolts with pin, ref. MBF2110AB-05-150 and modified hybrid joints. Using titanium driven blind bolts with pin instead of ordinary hammer-bucked rivets, can improve the fatigue life of element made of aluminum alloy AW 2024T3. There are advantages of replacing riveted joints with modified hybrid (rivet & adhesive) joints in threefold increase in fatigue life of repaired airframe structures.
    Źródło:
    Eksploatacja i Niezawodność; 2021, 23, 1; 165-175
    1507-2711
    Pojawia się w:
    Eksploatacja i Niezawodność
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Stabilization of Deep Roadways in Weak Rocks Using the System of Two-level Rock Bolts
    Autorzy:
    Tran, Tuan Minh
    Do, Ngoc Thai
    Dang, Trung Thanh
    Nguyen, Duyen Phong
    Vo, Trong Hung
    Powiązania:
    https://bibliotekanauki.pl/articles/2019328.pdf
    Data publikacji:
    2021
    Wydawca:
    Polskie Towarzystwo Przeróbki Kopalin
    Tematy:
    deep roadways
    large deformation mechanism
    control techniques
    numerical simulation
    weak rocks
    rock bolts
    odkształcenia
    symulacja numeryczna
    kotwie górnicze
    Opis:
    Large rock mass deformation around deep roadways in the weak rocks was a significant problem in mining activities in Vietnam and other countries. The excavation of roadways leads to high releasing stress, which exceeds the peak strength of spalling surrounding rock and causes it to enter the post-failure stage. Tensile failures then initiate and develop around the roadways, which causes the fragmentation, dilation, and separation of surrounding rock. The capacity of the primary support system is low, which results in a severe contraction in the whole section of roadways, which requires finding solutions to prevent the deformation of rock mass around roadways and technical solutions from stabilizing for deep roadways. To stability analysis of roadways can be applied analytical, experimental, semi-experimental, and numerical methods. This paper introduces the prevention mechanism of large deformation of rock mass around roadways using 2-level rock bolts. The research results show that using the system of two-level rock bolts can reduce the values of tensile stress on the boundary of roadways range from 10 to 15% compared with only one. The importance of the total displacement of rock mass on the boundary of roadways will be reduced from 3.47 to 13.85% using six long cable bolts.
    Źródło:
    Inżynieria Mineralna; 2021, 2; 157--166
    1640-4920
    Pojawia się w:
    Inżynieria Mineralna
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of applying supplementary web plates on structural joint moment resistance and rotational stifness
    Wpływ zastosowania nakładek wzmacniających środnik na nośność i sztywność doczołowego węzła śrubowego
    Autorzy:
    Urbańska-Galewska, E.
    Deniziak, P.
    Powiązania:
    https://bibliotekanauki.pl/articles/402497.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Świętokrzyska w Kielcach. Wydawnictwo PŚw
    Tematy:
    steel structures
    bolted joints
    supplementary web plates
    T-stubs with 4 bolts
    konstrukcje stalowe
    połączenia śrubowe
    nakładki wzmacniające środnik
    Opis:
    Continual trend to simplify structural elements and find less time-consuming solutions on construction site as well as inevitable increase in labour costs determine for instance elimination of those technological steps that are difficult to automation. Welding additional reinforcements and web stiffeners are great examples of such a step. The method presented in EN 1993-1-8 [8] is a result of long-term studies focused on calculating the moment resistance and stiffness of joints without transverse web stiffeners. Design calculations shown in this paper are based on resistance and stiffness growth analysis applying supplementary web plates. Authors consider validity of this solution due to construction effort and building durability remembering about minimization of the costs.
    Źródło:
    Structure and Environment; 2014, 6, 2; 11-17
    2081-1500
    Pojawia się w:
    Structure and Environment
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Strength testing of rock and ground anchor rods under static and dynamic loads
    Badania wytrzymałościowe żerdzi kotwi górniczych i gruntowych przy obciążeniu statycznym i dynamicznym
    Autorzy:
    Frąc, Witold
    Pytlik, Andrzej
    Pacześniowski, Krzysztof
    Powiązania:
    https://bibliotekanauki.pl/articles/2106544.pdf
    Data publikacji:
    2020
    Wydawca:
    Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
    Tematy:
    rock bolts
    soil nails
    injection micropiles
    resistance to static and dynamic load
    fatigue tests
    kotwie górnicze
    gwoździe gruntowe
    mikropale iniekcyjne
    wytrzymałość na obciążenie statyczne i dynamiczne
    badania zmęczeniowe
    Opis:
    Various types of anchor rods are commonly used for rock mass and soil reinforcement, produced either as full-section steel rods or tubes with threads along their entire length, which are used for the injection of liquid binders. This paper presents the methodology and sample results of strength tests of self-drilling injection anchor rods with R32 rope threads. Such rods are used both in underground mining and in geoengineering under static and dynamic (impact) loads. The results of tests of injection micropiles with trapezoidal thread diameters in the range of T51–T111 mm, used mainly in geoengineering, are provided as well. This paper also presents the basic requirements for the fatigue loading of nails and injection micropiles used in geoengineering, based on standards and the European Assessment Document (EAD), applicable in the European Union.
    Do wzmacniania górotworu oraz gruntu powszechnie stosuje się różnego typu żerdzie kotwi wykonane zarówno w postaci stalowych prętów o pełnym przekroju, jak i rur z gwintem na całej długości, które służą do iniekcji spoiw płynnych. W artykule przedstawiono metodykę oraz przykładowe wyniki wytrzymałościowych badań żerdzi kotwi samowiercących iniekcyjnych z gwintem falistym R32. Tego typu żerdzie stosowane są zarówno w górnictwie podziemnym, jak i geoinżynierii, przy obciążeniu statycznym i dynamicznym – o charakterze impulsowym (udarowym). Przedstawiono również wyniki badań mikropali iniekcyjnych o średnicach gwintu o zarysie trapezowym z zakresu T51–T111 mm, stosowanych głównie w geoinżynierii. Na podstawie norm oraz dokumentu EAD (European Assessment Document), obowiązującego w Unii Europejskiej, w artykule przedstawiono także podstawowe wymagania w zakresie obciążeń zmęczeniowych, stawiane gwoździom i mikropalom iniekcyjnym stosowanym w geoinżynierii.
    Źródło:
    Mining – Informatics, Automation and Electrical Engineering; 2020, 58, 2; 71-78
    2450-7326
    2449-6421
    Pojawia się w:
    Mining – Informatics, Automation and Electrical Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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