scholarly journals Express method for the testing of tribotechnical properties of lubricants

2021 ◽  
pp. 65-69
Author(s):  
K. V. Moiseev ◽  
◽  
A. I. Popenov ◽  
R. N. Bakhtizin ◽  
◽  
...  
Keyword(s):  
Rolling Resistance ◽  
Angular Speed ◽  
Metallographic Analysis ◽  
Well Drilling ◽  
Outer Race ◽  
Data Registration ◽  
Tribotechnical Properties ◽  
Resistance Moment ◽  
Rolling Elements ◽  
The Moment

The paper presents the results of experimental study of the tribotechnical properties of lubricants on a unit that simulates the geometric, kinematic and force similarity of well drilling conditions. Bearings with different radial clearances and the same chemical-thermal treatment were investigated. Data registration was carried out on cathode, loop oscilloscopes and electronic recorders. The load on the bearing, the moment of rolling resistance on the journal, and the angular speed of rotation of the outer race were recorded. The temperature was registered using artificial and semiartificial thermocouples. A strobotachometer was used to determine the portable speed of the rolling bodies. The external appearance of all rolling elements was investigated, metallographic analysis of thin surface layers of all rolling elements was carried out, mathematical processing of test results was carried out. It is shown that for the express assessment of the tribotechnical properties of lubricants, the amplitude value of the oscillation of the rolling resistance moment can be used. Keywords: friction; lubrication; tribotechnical Properties; drilling.

An improved model for investigating the vibration characteristics of ball bearing owing to outer race waviness under high speed

2021 ◽  
Vol 69 (2) ◽  
pp. 89-101
Author(s):  
Pingping Hou ◽  
Liqin Wang ◽  
Zhijie Xie ◽  
Qiuyang Peng
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Vibration Measurement ◽  
Vibration Frequencies ◽  
Outer Race ◽  
Response Characteristics ◽  
Lagrange’S Equation ◽  
Rolling Elements ◽  
Initial Clearance ◽  
Improved Model

In this study, an improved model for a ball bearing is established to investigate the vibration response characteristics owing to outer race waviness under an axial load and high speed. The mathematical ball bearing model involves the motions of the inner ring, outer ring, and rolling elements in the radial XY plane and axial z direction. The 2Nb + 5 nonlinear differential governing equations of the ball bearing are derived from Lagrange's equation. The influence of rotational speed and outer race waviness is considered. The outer race waviness is modeled as a superposition of sinusoidal function and affects both the contact deformation between the outer raceway and rolling elements and initial clearance. The MATLAB stiff solver ODE is utilized to solve the differential equations. The simulated results show that the axial vibration frequency occurred at l fc and the radial vibration frequencies appeared at l fc fc when the outer race waviness of the order (l) was the multiple of the number of rolling elements (k Nb) and that the principal vibration frequencies were observed at l fc fc in the radial x direction when the outer race waviness of the order (l) was one higher or one lower than the multiple of the number of rolling elements (k Nb 1). At last, the validity of the proposed ball bearing model was verified by the high-speed vibration measurement tests of ball bearings.

scholarly journals Modeling and Dynamic Analysis of Spherical Roller Bearing with Localized Defects: Analytical Formulation to Calculate Defect Depth and Stiffness

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Behnam Ghalamchi ◽  
Jussi Sopanen ◽  
Aki Mikkola
Keyword(s):  
Dynamic Model ◽  
Contact Stiffness ◽  
Roller Bearing ◽  
Measurement Data ◽  
Contact Forces ◽  
Hertzian Contact ◽  
Radial Clearance ◽  
Outer Race ◽  
Rolling Elements ◽  
Localized Defects

Since spherical roller bearings can carry high load in both axial and radial direction, they are increasingly used in industrial machineries and it is becoming important to understand the dynamic behavior of SRBs, especially when they are affected by internal imperfections. This paper introduces a dynamic model for an SRB that includes an inner and outer race surface defect. The proposed model shows the behavior of the bearing as a function of defect location and size. The new dynamic model describes the contact forces between bearing rolling elements and race surfaces as nonlinear Hertzian contact deformations, taking radial clearance into account. Two defect cases were simulated: an elliptical surface on the inner and outer races. In elliptical surface concavity, it is assumed that roller-to-race-surface contact is continuous as each roller passes over the defect. Contact stiffness in the defect area varies as a function of the defect contact geometry. Compared to measurement data, the results obtained using the simulation are highly accurate.

Six Sigma to distinguish patterns in COVID-19 approaches

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Willem Salentijn ◽  
Jiju Antony ◽  
Jacqueline Douglas
Keyword(s):  
Six Sigma ◽  
Design Methodology ◽  
Similar Data ◽  
National Data ◽  
Common Cause ◽  
Content Type ◽  
Data Registration ◽  
The Moment ◽  
Special Causes ◽  
Cross National

PurposeCOVID-19 has changed life as we know. Data are scarce and necessary for making decisions on fighting COVID-19. The purpose of this paper is to apply Six Sigma techniques on the current COVID-19 pandemic to distinguish between special cause and common cause variation. In the DMAIC structure, different approaches applied in three countries are compared.Design/methodology/approachFor three countries the mortality is compared to the population to distinguish between special cause variation and common cause variation. This variation and the patterns in it are assessed to the countries' different approaches to COVID-19.FindingsIn the DMAIC problem-solving approach, patterns in the data are distinguished. The special cause variation is assessed to the special causes and approaches. The moment on which measures were taken has been essential, as well as policies on testing and distancing.Research limitations/implicationsCross-national data comparisons are a challenge as countries have different moments on which they register data on their population. Furthermore, different intervals are taken, varying from registering weekly to registering yearly. For the research, three countries with similar data registration and different approaches in fighting COVID-19 were taken.Originality/valueThis is the first study with Master Black Belts from different countries on the application of Six Sigma techniques and the DMAIC from the viewpoint of special cause variation on COVID-19.

Dynamic Analysis of Ball Bearings Due to Clearance Effect

2009 ◽  
Author(s):  
S. H. Upadhyay ◽  
S. C. Jain ◽  
S. P. Harsha
Keyword(s):  
Chaotic Behavior ◽  
Equations Of Motion ◽  
Peak Frequency ◽  
System Response ◽  
Ball Bearings ◽  
Outer Race ◽  
Lagrange’S Equation ◽  
Rolling Elements ◽  
Machine Systems ◽  
The Individual

In this paper, the nonlinear dynamic behavior of ball bearings due to radial internal clearance and rotor speed has been analyzed. The approach presented in this paper accounts for the contact between rolling elements and inner/outer races. The equations of motion of a ball bearing are formulated in generalized coordinates, using Lagrange’s equation considering the vibration characteristics of the individual constitute such as inner race, outer race, rolling elements. The effects of speed of rotor in which rolling element bearings shows periodic, quasi-periodic and chaotic behavior are analyzed. The results also show the intermittent chaotic behavior in the dynamic response is seen to be strongly dependent on the speed of the rotor. The results are obtained in the form of frequency responses. The validity of the proposed model verified by comparison of frequency components of the system response with those obtained from experiments. The peak-to-peak frequency response of the system for each speed is obtained. The current study provides a powerful tool design and health monitoring of machine systems.

Rolling Resistance Moment-Based Adhesion Characterization of Microspheres

2008 ◽  
Vol 84 (12) ◽  
pp. 996-1006 ◽  
Author(s):  
W. Ding ◽  
H. Zhang ◽  
C. Cetinkaya
Keyword(s):  
Rolling Resistance ◽  
Resistance Moment

Nanoparticle Detachment Using Shock Waves

2005 ◽  
Vol 219 (3) ◽  
pp. 91-102 ◽  
Author(s):  
D Zhou ◽  
A. T. J. Kadaksham ◽  
M. D. Murthy Peri ◽  
I Varghese ◽  
C Cetinkaya
Keyword(s):  
Shock Waves ◽  
Direct Simulation Monte Carlo ◽  
Rolling Resistance ◽  
Nanoparticle Interactions ◽  
Gas Molecule ◽  
Resistance Moment ◽  
Discrete Nature ◽  
Frequency Excitation ◽  
Gas Molecules ◽  
Simulation Monte Carlo

The fundamentals of nanoparticle detachment at the sub-100nm level using pulsed laser-induced plasma (LIP) shock waves are investigated in the current study. Two detachment mechanisms based on rolling resistance moment and rolling by resonant frequency excitation are identified as possible detachment mechanisms for nanoparticles. The gas molecule-nanoparticle interactions are studied using the direct simulation Monte Carlo method to gain knowledge about the nature of the detachment forces and moments acting on a nanoparticle in the LIP shock wave field. The discrete nature of the gas molecules colliding with the particle on the sub-100 nm length scale is linked to the stochastic transient moment experienced by the particle. Both experimental and computational findings of the current study indicate that nanoparticle detachment at the sub-100 nm level is possible by LIP shock waves.

scholarly journals Analisa Getaran Akibat Kerusakan Deep Grove Ball Bearing Seri 6003RS

2019 ◽  
Vol 9 (02) ◽  
pp. 39-43
Author(s):  
Muhamad Riva’i ◽  
Nanda Pranandita
Keyword(s):  
Ball Bearing ◽  
Rolling Bearing ◽  
Internal Diameter ◽  
Outer Diameter ◽  
Outer Race ◽  
Deep Groove ◽  
Deep Groove Ball Bearing ◽  
Rolling Element ◽  
Rolling Elements ◽  
Vibration Measuring

Measurement of the damage of elements in bearing can be by measuring the vibration generated in the form of a frequency signal when the pad is rotating. Measurement of vibration on the bearing by using vibration measuring instrument. Damage to the rolling bearing includes damage to the cage, outer ring, inner ring and balls. The rolling bearings used in this study are deep groove ball bearing type 6003 RS with internal diameter (d) = 17 mm, outer diameter (D) = 35 mm, bearing thickness (B) = 10, number of rolling elements (Nb) = 10 pieces, and the diameter of the rolling element (Bd) = 4.75 mm. In the rotation of the bearing (Fr) = 2003 rpm (33.38 Hz) we found the experimental results of bearings that have been damaged in the outer race at 138 Hz frequency, inner race damage at 196 Hz frequency, (ball) at a frequency of 88.8 Hz and cage damage at a frequency of 13.8 Hz.

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