EVALUATING THE INFLUENCE OF BENDING STRESS ON A 1H18N9 STEEL SHAFT WEAR PROCESS IN A WATER LUBRICATED SLIDING BEARING WITH A RUBBER BUSHING

Tribologia ◽  
2017 ◽  
Vol 276 (6) ◽  
pp. 79-85 ◽  
Author(s):  
Ewa PIĄTKOWSKA
Keyword(s):  
Wear Intensity ◽  
Bending Stress ◽  
Sliding Bearings ◽  
Sliding Bearing ◽  
Wear Process ◽  
Rubber Bearing ◽  
Before And After ◽  
Rubber Bushing ◽  
Bending Stresses ◽  
Lubricated Sliding

The issue of excessive wear of shaft journals co-working with a rubber bearing has been unexplained so far. Premature and sometimes very intensive wear of ship sliding bearings in water conditions is the reason for carry out very expensive and more frequent than expected repairs. The authors (E. Piątkowska, W. Litwin) made an attempt to find a case that influences the value of this wear described in the paper “Attempt at Evaluating the Influence of Bending Stress on Shaft Wear Process in Water Lubricated Sliding Bearing with Rubber Bush” (TRIBOLOGY 1/2017). These studies, however, did not explain the dependency of the wear process but showed how to progress further to find the answer to the question about the effect of bending stress on shaft wear. The research is continued on a modified test stand, and their results are presented in this paper. The profilographometer was used to evaluate the wear of the journal shaft. To compare wear intensity, roughness profiles have been 'removed' from the journals both before and after co-operation. They were compared in terms of bending stresses and bending moments.

ATTEMPT AT EVALUATING THE INFLUENCE OF BENDING STRESS ON SHAFT WEAR PROCESSES IN WATER LUBRICATED SLIDING BEARING WITH A RUBBER BUSHING

Tribologia ◽  
2018 ◽  
Vol 271 (1) ◽  
pp. 81-86 ◽  
Author(s):  
Ewa PIĄTKOWSKA ◽  
Wojciech LITWIN
Keyword(s):  
Experimental Tests ◽  
Test Stand ◽  
Test Series ◽  
Bending Stress ◽  
Sliding Bearing ◽  
Rubber Bushing ◽  
Bending Stresses ◽  
Research Goal ◽  
Hydropower Industry ◽  
Shaft Journal

Water lubricated bearings find increasingly wide application in shipbuilding or the hydropower industry, with the popularity stemming from their numerous advantages. Unfortunately, as it turns out, water lubricated bearings do not always meet expectations, because, on occasion, they become subject to intense, premature wear, which requires costly repair. One of the still unexplained phenomena is the process of excessive bearing wear, in particular, that of shaft journal co-working with rubber bushings. The research goal was to evaluate the influence of shaft bending stress on the degree of its wear. Experimental tests were carried out on a purpose-designed test stand. The results of the first test series confirmed that the shaft bending stresses do have impact on the magnitude of wear.

Development of the mathematical model for assessing the optimal measurement step when surveying the depth of the underground pipeline from the ground

2020 ◽  
Vol 10 (4) ◽  
pp. 364-371
Author(s):  
Ruslan V. Aginey ◽  
◽  
Rustem R. Islamov ◽  
Alexey A. Firstov ◽  
Elmira A. Mamedova ◽  
...  
Keyword(s):  
Mathematical Models ◽  
Survey Data ◽  
Ground Surface ◽  
Maximum Error ◽  
Large Error ◽  
Bending Stress ◽  
Buried Pipeline ◽  
Optimal Measurement ◽  
Pipeline Section ◽  
Bending Stresses

Existing methods for estimating the bending stresses of buried pipeline section based on the survey data for the depth of the axis of the pipeline from the ground surface are characterized by a large error between the real values of the bending stress and the values of the bending stress obtained from the calculation results based on the survey data. The purpose of this study is to improve the methodology for calculating the bending stresses of buried pipeline section based on the results of determining the depth of the axis of the pipeline from the ground surface, taking into account the design features of the pipeline and the used search equipment. Mathematical models are proposed that allow for the set value of the maximum error in determining bending stresses for a particular pipeline to choose the optimal measurement step before the survey, which will allow to reduce the error. Explanations are given on the choice of the maximum step of the study based on the strength characteristics of the pipeline. A calculation is provided that confirms the adequacy of the developed mathematical models and the possibility of their application in practice.

Analysis of Traction Characteristics of Grease-Lubricated Sliding Bearing

2013 ◽  
Vol 655-657 ◽  
pp. 640-643
Author(s):  
Bo Yuan Yang ◽  
Xiaofan Yan ◽  
Bing Su
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Room Temperature ◽  
Extreme Pressure ◽  
Test Rig ◽  
Sliding Bearing ◽  
Traction Coefficient ◽  
Lubrication Effect ◽  
Lubricated Sliding

Adopting the test rig of traction characteristics of grease-lubricated sliding bearing, the practical condition of sliding bearing was simulated and the traction coefficient of DGG Grease under different temperature, velocity and load was tested. Besides, the traction characteristics of the grease were also elaborated. The results indicate that the traction coefficient increases when the temperature gradually rises from room temperature while it gradually decreases when the temperature exceeds 85°C. Under the condition of high temperature and high pressure, the extreme pressure additive has obvious effects, the traction coefficient reducing and maintaining constant, so a better lubrication effect is realized.

scholarly journals A Novel Method for Tooth Bending Stress Calculation of Gears With Asymmetric Teeth

2021 ◽  
Author(s):  
Oguz DOGAN ◽  
Celalettin YUCE ◽  
Fatih KARPAT
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Experimental Studies ◽  
Element Model ◽  
Bending Stress ◽  
Element Analysis ◽  
Stress Calculation ◽  
Bending Stresses ◽  
New Equation ◽  
Asymmetric Factor

Abstract Today, gear designs with asymmetric tooth profiles offer essential solutions in reducing tooth root stresses of gears. Although numerical, analytical, and experimental studies are carried out to calculate the bending stresses in gears with asymmetric tooth profiles a standard or a simplified equation or empirical statement has not been encountered in the literature. In this study, a novel bending stress calculation procedure for gears with asymmetric tooth profiles is developed using both the DIN3990 standard and the finite element method. The bending stresses of gears with symmetrical profile were determined by the developed finite element model and was verified by comparing the results with the DIN 3990 standard. Using the verified finite element model, by changing the drive side pressure angle between 20° and 30° and the number of teeth between 18 and 100, 66 different cases were examined and the bending stresses in gears with asymmetric profile were determined. As a result of the analysis, a new asymmetric factor was derived. By adding the obtained asymmetric factor to the DIN 3390 formula, a new equation has been derived to be used in tooth bending stresses of gears with asymmetric profile. Thanks to this equation, designers will be able to calculate tooth bending stresses with high precision in gears with asymmetric tooth profile without the need for finite element analysis.

scholarly journals 309 Evaluation test of water-lubricated sliding bearing materials for marine coupling

2005 ◽  
Vol 2005.58 (0) ◽  
pp. 99-100
Author(s):  
Michiyoshi Kono ◽  
Tuyoshi Kawazoe ◽  
Tetuya Okumura ◽  
Akira Nakasima ◽  
Hidesirou Moritaka ◽  
...  
Keyword(s):  
Sliding Bearing ◽  
Evaluation Test ◽  
Bearing Materials ◽  
Lubricated Sliding

Comparison of the Friction and Wear Properties of PTFE Coatings under Vacuum Conditions before and after Gamma Irradiation

2011 ◽  
Vol 311-313 ◽  
pp. 1177-1181 ◽  
Author(s):  
Xing Dong Yuan ◽  
Bin Xu ◽  
Xiao Jie Yang ◽  
Hai Long Ma
Keyword(s):  
Friction Coefficient ◽  
Gamma Irradiation ◽  
Friction And Wear ◽  
Sliding Velocity ◽  
Wear Properties ◽  
Sliding Speed ◽  
Wear Process ◽  
Before And After ◽  
Three Stages ◽  
Friction And Wear Properties

The friction and wear properties of Polytetrafluoroethylene (PTFE) coatings before and after gamma irradiation were studied under vacuum conditions. Experimental results indicated that the friction and wear properties of PTFE coatings were improved by gamma irradiation. Results showed that the wear process of PTFE coatings before and after gamma irradiation consists of three stages. The steps for the irradiated PTFE are slightly longer than that for the non-irradiated samples. The friction coefficient of irradiated PTFE coatings reduces slightly compared to that of the non-irradiated samples. The friction coefficients of the PTFE coatings before and after gamma irradiation first increase with the increase of sliding velocity and then decrease with the increase of sliding velocity, and The friction coefficient of PTFE coatings before and after gamma irradiation decreases with the increase of load. The wear of irradiated PTFE coatings is slightly lower than that of non-irradiated PTFE coatings. The wear of PTFE coatings before and after gamma irradiation first decreases with the increase of sliding speed and then increases as the sliding speed increases. The wear of PTFE coatings first decreases with the increase of load and then increases with the increase of load. Scanning electron microscope (SEM) was utilized to investigate the worn surfaces.

Relationship between Feedrate and Fatigue Life of Al7075-T6 Specimens before and after Shotpeening

2008 ◽  
Vol 580-582 ◽  
pp. 109-112 ◽  
Author(s):  
Hyoung Tae Kim ◽  
Ki Hoon Shin
Keyword(s):  
Fatigue Life ◽  
Loading Conditions ◽  
Mean Diameter ◽  
Before And After ◽  
Bending Stresses ◽  
The Mean ◽  
The Relationship

This paper presents a study on the relationship between feedrate and fatigue life of Al7075-T6 specimens before and after shotpeening. For this purpose, six groups of specimens, each of which consists of eight specimens, were first machined at six different feedrates (0.05, 0.10, 0.15, 0.20, 0.25, 0.30 mm/rev). Half of eight specimens in each group were then peened and the others remained un-peened. Next, the fatigue life was measured by using 4-point rotary bending machine. One observation was that the fast the feedrate was, the large the mean diameter of a specimen was. To apply the same bending stresses in all cases, different loading conditions were thus recalculated and applied to specimens based on their mean diameters. Finally, the effect of feedrate on the fatigue life was estimated by comparing twelve sets of specimens (six groups times two sets, peened and un-peened).

Analysis and Models for the Friction Coefficient of a Sliding Bearing

2013 ◽  
Vol 395-396 ◽  
pp. 826-830
Author(s):  
Bao Ming Wang ◽  
Jin Xin Xu ◽  
Fei Zhu ◽  
Zai Xin Wu
Keyword(s):  
Friction Coefficient ◽  
Rotational Speed ◽  
Moving Average ◽  
Grey System Theory ◽  
Grey System ◽  
Sliding Bearings ◽  
Sliding Bearing ◽  
Non Linear ◽  
Grey Relational Grade ◽  
Grey Relational

In this paper, the analyzing and modeling of the friction coefficient in sliding bearing is reported. Based on the grey system theory, the effects of rotational speed and load on the friction coefficient of the sliding bearings are investigated. The grey relational grade is an important parameter to measure the effects of rotational speed and load on friction coefficient of the sliding bearings. The grey relational grade analysis shows that load has an even more significant effect upon the friction coefficient compared with rotational speed. On the basis of analyzing and processing the experimental data, a nonlinear model for friction coefficient of a sliding bearing have been set up by NARMAX Non-Linear Auto-Regressive Moving Average with Exogenous Input. It was found that the NARMAX Non-Linear model has good accuracy and is applicable for the calculation of friction coefficient in sliding bearing.

Combined Stresses in an Orthotropic Plate Having a Finite Crack

1961 ◽  
Vol 28 (3) ◽  
pp. 372-378 ◽  
Author(s):  
D. D. Ang ◽  
M. L. Williams
Keyword(s):  
Orthotropic Plate ◽  
Fracture Initiation ◽  
Square Root ◽  
Bending Stress ◽  
Important Work ◽  
Combined Stresses ◽  
Finite Crack ◽  
Bending Stresses ◽  
Circumferential Distribution ◽  
Root Character

Using a formulation in integral equations, a solution for the combined extension-classical bending stress and displacement solution is presented for the case of an infinite orthotropic flat plate containing a finite crack. While the solution can be expressed in closed form for the entire field, primary emphasis is placed upon the stresses near the crack point. Qualitatively, no major difference in behavior due to orthotropy was found although certain quantitative features are noted, mainly as a function of the characteristic rigidity ratio (Ex/Ey)1/2. The inverse square-root character of the isotropic stress bending and extension is not changed by orthotropy, although amplitudes and distribution are affected. Account is taken of recent important work by Knowles and Wang dealing with Reissner bending of the plate which shows that the extensional and surface bending stresses are identical in singular character and circumferential distribution. A bending-extension interaction curve for fracture initiation is derived and shown to be linear when based upon the more exact bending theory.

Deformation and Bending Stress Analysis of a Three-dimensional, Thin-rimmed Gear

2001 ◽  
Vol 124 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Shuting Li
Keyword(s):  
Critical Stress ◽  
Gear Tooth ◽  
Three Dimensional ◽  
Deformation Model ◽  
Tooth Root ◽  
Bending Stress ◽  
The Finite Element Method ◽  
Stress Point ◽  
Bending Stresses ◽  
The Web

This paper analyzed the deformations and bending stresses of a three-dimensional (3D), thin-rimmed gear (TRG) through using the finite element method (FEM) and a whole gear deformation model. The gear’s deformations and stresses at every part are analyzed in detail. In contrast with tooth bending deformations of a solid gear, 3D-TRG has not only tooth bending deformations, but also rim and web bending deformations. This paper found that the thin rim and web share about 70% deformations in the total deformations of the 3D-TRG and the gear tooth share only about 30%. It is also pointed out by this paper that not only the root stresses of the 3D-TRG are much greater than the solid gear because of the rim and web deformations, but also there are much greater stresses existing in the joint of the thin rim and the web. Especially, when the rim thickness becomes very thin, stresses at the joint shall become much greater than the root stresses. It is very necessary to regard the joint as the second critical stress point as well as the tooth root when to design 3D-TRG.

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