Autor: Sikora, W. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Selected problems of experimental investigation of dynamically loaded journal bearings
Autorzy:: Sikora, J.
Kłopocki, J.
Majewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/242758.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: combustion engine
engine parts
bearings
tribology
bearing fatigue
Opis:: In the paper some problems concerning relations between external bearing loadings and critical lining stresses are described for test stand with rotating load vector. According to the standard ISO 7905/1 this type of test stand, for dynamically loaded slide bearing, is recommended as a basic research unit for material testing in a complete bearing unit. The lining stress calculation results occurred being dependent on applied calculation model. The influence of sliding surface shape and housing stiffness on bearing fatigue have been considered. The MWO-stand operational principle, standard tested half-bearing, bearing housing of rigid profile, bearing housing of edge elastic profile, distribution of radial and circumferential stress in the slide layer of the bearing bush tested in MWO stand, typical damage of the bearing tested, finite element model geometry for bush and housing are illustrated in the paper. Performed calculations revealed that neglecting the shape and dimensions of the housing in calculation model of the contemporary thin-walled multilayer bearing bushes are leading to incorrect evaluation of critical stresses leading to fatigue cracks in slide layers of the bearing tested in machines with rotary load vector. That kind of bearing alloys is not employed in highly dynamically loaded bearings of contemporary machines, especially in IC engine bearing systems.
Źródło:: Journal of KONES; 2007, 14, 4; 433-440
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 2.

Tytuł:: Mechanism of the fatigue cracks development in bearing slide layer
Autorzy:: Sikora, J.
Kłopocki, J.
Majewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/245360.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: bearings
bearing slide layer
fatigue cracks
fracture mechanics
lubrication
fractography
Opis:: In the paper some problems concerning relations between slide bearings fatigue resistance and the bearing material and structure characteristics of the slide layer have been considered on the basis of bibliographic descriptions. In particular the mechanisms of the nucleation and development of cracks were discussed as dependent not only on the bearing dynamic loading pattern and number of loading cycles but also on the slide layer geometry and its structure design. Two basic types of the possible fatigue cracks were distinguished: structural and "magistral" ones. The process of the fatigue rapture formation and development were analyzed from the viewpoint of fracture mechanics according to the Nemec 's model. In particular types of fatigue cracks, structural cracks (cross-section of the bearing surface layer) and mechanism of fatigue crack development from the viewpoint of fracture mechanics, as well as fracture of magistral type (on the surface of the bearing) almost perpendicular to the circular direction of the bush, fatigue durability for various types of fracture developments, Fractures on the boundary of Si particle in AlSnl2 Si4 alloy and Sn particle in AlSn20 alloy, fractures on the boundary of the intermetallic compound grain CuAl2 in AlSn20 alloy are presented in the paper.
Źródło:: Journal of KONES; 2009, 16, 4; 423-427
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 3.

Tytuł:: Fatigue resistance investigation of the IC engine MB11 bearings, working under conditions of dynamic unidirectional loadings
Autorzy:: Sikora, J.
Kłopocki, J.
Majewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/243868.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: transport
plain bearings
bearings testing
bearings fatigue
Opis:: The slide bearing material MB11 fatigue resistance has been investigated with the application of SMOK - test stand in which dynamic unidirectional loadings to the test bearing is generated. Slide bearing layer consists of the bronze (Cu Pb22 Sn 3) sintered to the steel shell. Each of the tested bearing has been subject to the standard 20-hour test, under conditions of the full fluid lubrication. Methodology of the experiments, metallurgical test results and fractographic description of the lining fatigue crack zone are presented. The values of the fatigue strength parameters are also estimated. For the loading pattern that is characteristic for the test devices such as SMOK tester, because of the nominally negative high normal stresses in the damage area, the mechanisms of cracks generation could be explained as follows: yield stress can be reached when during compression at the bearing working temperature the local plastic deformation can appear. After completing the test, in the region of plastic deformation, the tensile stresses can be generated due to the temperature reduction. Slide material is much more sensitive to the tensile loadings than to the compressive one, especially in the area that is weaken by empty spaces. That might be reason for cracks generation. Additionally in the case of the thin-wall bearing shell, assembled in the elastic housing, the circumferentially oriented cracks can appear. It has been observed for high bearing loadings applied on the SMOK tester. Fatigue cracks in the MB11 material tested on the SMOK machine are of the surface net pattern, positioned paralleled to the slide surface (Fig. 8). Mainly structural cracks can be noticed when analyzing the metallographic description. This is related to the porosity of the alloy structure. This is much different from the aluminum alloy structure (the bearing alloy that was previously investigated) where arterial structures of cracks were dominant. The slide surface is the place of cracks nucleation. When in slide layer there are bigger soft material elements or voids it is also possible to observe generation of cracks in any place of the bulk thickness. During consequent development of the process the micro-cracks are spreading out and going to the next defected parts of the alloys. The continuous surface of separation is then developed. The micro-cracks space net which is typical for this kind of damage is not precisely oriented but rather random. The eventually oriented fracture is due to the not uniform structure.
Źródło:: Journal of KONES; 2008, 15, 2; 449-456
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 4.

Tytuł:: Some problems of slide bearing material fatigue evaluation
Autorzy:: Sikora, J.
Kłopocki, J.
Majewski, W.
Kurzych, K.
Powiązania:: https://bibliotekanauki.pl/articles/242756.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: bearings
tribology
bearing testing
fatigue investigations
fatigue performance
Opis:: A slide bearing alloy resistance against fatigue failures have been investigated for three different lubricants, different heat loadings and different stress ratio K values. The research methods and data handling procedures for determination of particular parameter effects on fatigue strength have been described and analysed for experiments that were set and performed in laboratory tester SKMR-2. Main and interaction effects of lubricant and stress ratio factors on bearing material fatigue strength have been analysed. Design scheme of the SKMR-2 head unit, Standard tested half-bearing, fatigue failures on the surface of the specimen, cross-section through the damaged surface layer of the specimen, fatigue limit stress amplitude vs. temperature and kind of oil, main effect of stress ratio, main effects of temperature and oil are illustrated in the paper. Main conclusions are cover in statements that fatigue strength of the bearing material is affected, to the highest degree, by the mechanical stress value and stress ratio and resistance to the fatigue cracks is being reduced for higher tensional stress, increase in temperature is resulting in decreasing of the fatigue strength rating values, fatigue strength of the slide layer is considerably dependent on the type of the used lubricant interactions of the type of the lubricants, their temperatures, loading stress ratio have been noticed.
Źródło:: Journal of KONES; 2007, 14, 4; 427-432
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Informacja

Wyszukujesz frazę "Sikora, W." wg kryterium: Autor

Źródło danych

Dostawca treści

Kolekcja

Rok wydania

Wydawca

Temat

Autor

Typ dokumentu

Język