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1
Content available remote Influence of the lubricant properties on fatigue resistance of ic engine slide bearing lining
100%
Kłopocki J. , Kurzych K.
Journal of KONES
|
2002
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tom Vol. 9, No. 1-2
357-361
EN
In the paper the possible influance of the lubricant properties on the fatigue resistance of the IC slide bearing lining has been considered and sommee preliminary experimental tests were performed. The laboratory test stand SKMR – 2 for bending critical stress evaluation has been described. The test results obtaained for half – bearing made of AlSn20Cu1 material, for reversed bending load at the temperature 20C and two different test conditions: bearing being immersed in the lubrricating oil and bearing without contact with oil, are presented.
2
Content available remote Loading pattern effects on fatigue resistance of slide bearing lining
100%
Sikora J. , Kłopocki J.
Journal of KONES
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2003
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tom Vol. 10, No. 3-4
323-327
EN
In the paper the stress state in the journal bearing sliding layer subjected to the dynamic test loading of various load pattern is analysed . The testing apparatus MWO - generating rotational loading vector and SMOK test rig-with unidirectional dynamic loading vector are compared in this respect.
3
Content available remote Testing of fatigue strength limit of slide bearing materials
80%
Sikora J. , Kłopocki J. , Majewski W.
Journal of KONES
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2003
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tom Vol. 10, No. 1-2
259-267
EN
In the paper the results of fatigue strength experimental investigation of some bi- and three-metallic thin-walled bearing bushes are presented. Typical views of observed bearing surface fatigue cracks are shown. Critical values of tangential stresses in bearing lining have been calculated and discussed.
4
Content available remote Investigation on the IC engine lubricating oil effects on journal bearing life
80%
Sikora J. , Kłopocki J. , Majewski W. , Kurzych K.
Journal of KONES
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2003
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tom Vol. 10, No. 1-2
251-258
EN
In the paper the results of IC Engine sliding bearing lining fatigue strength experimental investigations are presented. In particular the effects of the lubricating oil type have been considered.
5
Content available Selected problems of experimental investigation of dynamically loaded journal bearings
80%
Sikora J. , Kłopocki J. , Majewski W.
Journal of KONES
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2007
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tom Vol. 14, No. 4
433-440
EN
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.
6
Content available Some problems of slide bearing material fatigue evaluation
80%
Sikora J. , Kłopocki J. , Majewski W. , Kurzych K.
Journal of KONES
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2007
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tom Vol. 14, No. 4
427-432
EN
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.
7
Content available remote Test rig for metallic plain strips of bearing material fatigue investigations - design and evaluation of properties
80%
Sikora J. , Kłopocki J. , Kurzych K. , Majewski W.
Journal of KONES
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1998
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tom Vol. 5, No. 1
274-279
EN
In the paper the necessity of bearing material fatigue investigation aimed at the assessment of their indurance limit for the plain strips of bearing materials is explained. The design and evaluation of SKMR-I tester that is following the recommendation of ISO 7905/3, are described. Preliminarily tests of AlSn20Cul material were performed confirming the ability of SKMR-I to assess the endurance limit for multilayer bearing materials.
8
Ocena tribologicznych efektów niektórych dodatków uzupełniających oleje smarowe.
80%
Kłopocki J. , Majewski W. , Sikora J.
Zeszyty Naukowe Politechniki Gdańskiej. Mechanika
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1998
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tom Nr 77(559)
41-56
PL
Przedstawiono wyniki badań wpływu wybranych dodatków do silnikowych olejów smarowych na właściwości tribologiczne smarowanych skojarzeń ciernych. Smary testowano w dwóch wariantach: bez dodatków uzupełniających oraz z dodatkami oferowanymi w handlu jako dodatki uniwersalne poprawiające odporność na zużycie, a także zmniejszające opory ruchu. W badaniach wykorzystano testy stosowane na aparacie czterokulowym, oparte na procedurach opisanych w normach.
9
Content available Fatigue resistance investigation of the IC engine MB11 bearings, working under conditions of dynamic unidirectional loadings
80%
Sikora J. , Kłopocki J. , Majewski W.
Journal of KONES
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2008
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tom Vol. 15, No. 2
449-456
EN
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.
10
Content available Mechanism of the fatigue cracks development in bearing slide layer
80%
Sikora J. , Kłopocki J. , Majewski W.
Journal of KONES
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2009
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tom Vol. 16, No. 4
423-427
EN
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.
11
Content available remote Fatigue test bearings with geometrically modyfied sliding surface
80%
Kłopocki J. , Majewski W. , Sikora J. , Siwek B.
Journal of KONES
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2004
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tom Vol. 11, No. 1-2
329-334
EN
In the paper a new type of a fatigue test bearing with geometrically modified sliding surface is described. Some of the advantages of these bearings are considered on the bases of comparison to standard solution bearing. Preliminary fatigue test results of the modified bearings are demonstrated and discussed.
12
Content available remote Research on fatigue resistance of metal hydrodynamic journal bearings
80%
Sikora J. , Kłopocki J. , Majewski W.
Journal of KONES
|
2000
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tom Vol. 7, No. 1-2
458-459
EN
The problems of fatigue resistance of the dynamically loaded journal bearings have been presented. The methodology for experimental investigation of critical loadings for bearing lining have been discussed.
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