Theoretical and experimental studies to predict vibration responses of defects in spherical roller bearings using dimension theory

Measurement ◽  
2020 ◽  
Vol 161 ◽  
pp. 107846 ◽  
Author(s):  
Surajkumar G. Kumbhar ◽  
Edwin Sudhagar P ◽  
R.G. Desavale
Keyword(s):  
Experimental Studies ◽  
Dimension Theory ◽  
Roller Bearings ◽  
Vibration Responses

Fault Diagnostics of Roller Bearings Using Dimension Theory

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Surajkumar G. Kumbhar ◽  
Edwin Sudhagar P
Keyword(s):  
Operating Conditions ◽  
Dimension Theory ◽  
Production Volume ◽  
Force Transmission ◽  
Rolling Bearings ◽  
Roller Bearings ◽  
High Production Volume ◽  
Vibration Responses ◽  
Multivariable Regression ◽  
High Production

Abstract Rolling bearings accomplishes a smoother force transmission between relative components of high production volume systems. An impending fault may cause system malfunction and its maturation lead to a catastrophic failure of the system that increases the possibility of unscheduled maintenance or an expensive shutdown. These critical states demand a robust failure diagnosis scheme for bearings. The present paper demonstrates a novel way to develop a dynamic model for the rotor-bearing system using dimensional analysis (DA) considering significant geometric, operating, and thermal parameters of the system. The vibration responses of faulty spherical roller bearings are investigated under various operating conditions for validation of the developed model. Multivariable regression analysis is performed to expose the potential of the approach in the detection of the bearing failure. Results obtained unveil the simple and reliable nature of the dynamic modeling using DA.

Image-Based Movement Analysis of Bearing Cages of Cylindrical Hybrid Roller Bearings

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Eberhard Abele ◽  
Lars Holland
Keyword(s):  
Rotational Speed ◽  
Experimental Studies ◽  
Movement Analysis ◽  
Movement Behavior ◽  
Operation Condition ◽  
Roller Bearings ◽  
Injection Molded ◽  
Motion Behavior

Movement analyses of bearings focusing on cage motion behavior are often conducted by simulations, typically by investigating the cage whirl. Some experimental studies exist in which a metal cage or a modified one is analyzed with sensors. This paper presents an image-based approach for investigating the cage motion of an injection molded, window-type cage under operation condition. Besides analyses at constant rotational speed, the cage center movement behavior for different accelerations is investigated.

scholarly journals METHOD OF THEORY OF DIMENSIONS IN EXPERIMENTAL RESEARCH OF SYSTEMS AND PROCESSES

2021 ◽  
pp. 233-240
Author(s):  
Vasyl Dmytriv ◽  
Ihor Dmytriv ◽  
Іvan Horodetskyy ◽  
Roman Horodniak ◽  
Taras Dmytriv
Keyword(s):  
Graphical Representation ◽  
Experimental Studies ◽  
Reynolds Numbers ◽  
Similarity Criteria ◽  
Dimension Theory ◽  
Factor Space ◽  
Experimental Modelling ◽  
Number Of Factors ◽  
D Model ◽  
Dimensionless Similarity

The method and parameters of experimental modelling of systems and processes in mechanical engineering are substantiated. The theory of similarity and dimensionality is used as an intermediate link between theory and experiment. The dimension of the factor space depends on the number of factors. The set of factors is grouped into dimensionless similarity criteria. The selected criteria are in certain dependence, such as the Galileo test, Euler and Reynolds numbers. Examples of application in experimental studies are given. The use of dimension theory in a factor-planned experiment allows reducing the number of factors, simplifies the mathematical interpretation of the response criterion and provides a graphical representation in the form of 3-D model.

Experimental studies on the vortex-induced forces of a 4:1 rectangular cylinder and two typical bridge girders

2019 ◽  
Vol 23 (3) ◽  
pp. 399-410
Author(s):  
Ming Li ◽  
Yanguo Sun ◽  
Yongfu Lei ◽  
Mingshui Li
Keyword(s):  
Oscillation Amplitude ◽  
Experimental Studies ◽  
Attack Angle ◽  
Box Girder ◽  
Pressure Distributions ◽  
Vibration Technique ◽  
Power Spectral ◽  
Vibration Responses ◽  
Frequency Components ◽  
The Mean

Wind tunnel tests were performed on a 4:1 rectangular (REC) cylinder, a trapezoidal (TRA) girder, and a typical streamlined (STR) box girder to investigate the vortex-induced forces and their spanwise correlations. First, using the free vibration technique, the vortex-induced vibration responses and the Strouhal number were investigated at different Scruton numbers and attack angles. Then, the mean and standard deviations of the vortex-induced pressure coefficients of the three models were analyzed through simultaneous pressure measurements. The power spectral density and the spanwise correlation of vortex-induced pressures at some typical points were also studied. Finally, the spanwise correlations of vortex-induced forces acting on the three models in the cases of different vibration amplitudes and attack angles were investigated. The results show that the attack angle has a significant effect on the vortex-induced pressure distributions for the three types of girders. The second frequency components of the vortex-induced pressure occur near the trailing edge of the upper surface for the three types of sections. The correlation of vortex-induced force decreases with the increase in the oscillation amplitude for the REC model, but becomes larger for the TRA and STR models. With the increase in the attack angle, the spanwise correlations of vortex-induced forces on the three sections become weaker, especially for the REC model.

An overview of dynamic modeling of rolling-element bearings

2020 ◽  
pp. 095745652094827
Author(s):  
Surajkumar G Kumbhar ◽  
Edwin Sudhagar P ◽  
RG Desavale
Keyword(s):  
Dynamic Behavior ◽  
Dynamic Modeling ◽  
Operating Conditions ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Roller Bearings ◽  
Rolling Element ◽  
Vibration Responses ◽  
Vibration Signature ◽  
Element Bearing

The marvelous uniqueness of vibration responses of faulty roller bearings can be simply observed through its vibration signature. Therefore, vibration analysis has been claimed as an effective tool not only for primitive detection but also for subsequent analysis. The dynamic behavior of roller bearings has been investigated by systematic modeling of system and its validation under diverse operating conditions. This article presents an overview of imperative marks in the development of dynamic modeling of rolling-element bearing, which especially predicted vibration responses of damaged bearings. This study aims to address dimensional analysis; a new and imperative way to model the dynamic behavior of rolling-element bearings and their real-time performance in a rotor-bearing system. The findings are described with influential advantages over earlier research to pinpoint the intention behind its development. A literature summary is trailed by remarkable findings and future directions for research.

Structural Damage Detection Using Auto/Cross-Correlation Functions Under Multiple Unknown Excitations

2014 ◽  
Vol 14 (05) ◽  
pp. 1440006 ◽  
Author(s):  
Pinghe Ni ◽  
Yong Xia ◽  
Siu-Seong Law ◽  
Songye Zhu
Keyword(s):  
Damage Detection ◽  
Correlation Functions ◽  
Structural Damage ◽  
Cross Correlation ◽  
Structural Parameters ◽  
Experimental Studies ◽  
Detection Methods ◽  
Structural System ◽  
Vibration Responses ◽  
Structural System Identification

Traditional structural system identification and damage detection methods use vibration responses under single excitation. This paper presents an auto/cross-correlation function-based method using acceleration responses under multiple ambient white noise or impact excitations. The auto/cross-correlation functions are divided into two parts. One is associated with the structural parameters and the other with the energy of the excitation. These two parts are updated sequentially using a two-stage method. Numerical and experimental studies are conducted to demonstrate the accuracy and robustness of the proposed method. The effects of measurement noise and number of measurement points on the identification results are also studied.

Experimental Validation of Wave Vibration Analysis of Complex Vibrations in a Two-Story Metallic Space Frame Based on the Timoshenko Bending Theory

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
C. Mei
Keyword(s):  
Cross Sections ◽  
Torsional Rigidity ◽  
Experimental Studies ◽  
Space Frame ◽  
Bending Vibrations ◽  
Space Frames ◽  
Out Of Plane ◽  
Vibration Responses ◽  
Steel Space Frame ◽  
Numerical Approaches

In a space frame, there exist in- and out-of-plane bending, axial, and torsional vibrations. The analysis of complex vibrations in such structures has relied mostly on numerical approaches. In this study, a wave-based analytical approach is applied to obtain solutions to vibrations in space frames. Both free and forced wave vibration responses are obtained, with bending vibrations modeled using the Timoshenko theory. A two-story steel space frame is built to validate the analytical results, and good agreements have been reached between the analytical and experimental studies. The effect of torsional rigidity adjustment on the accuracy of predicted vibrational responses in structures involving rotationally nonsymmetric cross sections is also examined.

Robust Balancing Approach for Rotating Machines Based on Fuzzy Logic

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Vinícius Nunes Carvalho ◽  
Bruno Ferreira Resende Rende ◽  
Arinan Dourado Guerra Silva ◽  
Aldemir Ap Cavalini ◽  
Valder Steffen
Keyword(s):  
Fuzzy Logic ◽  
Experimental Studies ◽  
Measurement Data ◽  
Data Sets ◽  
Rotating Machines ◽  
Rotating Machine ◽  
Fuzzy Transformation ◽  
Influence Coefficients ◽  
Fuzzy Logic Approach ◽  
Vibration Responses

Unbalance is one of the most common malfunctions found in rotating machines generating high vibration amplitudes that can lead to fatigue and wear of rotor elements. There are several well-known balancing techniques wherein one of the most widespread approaches is the so-called influence coefficients method (IC method). Aiming to increase the robustness of the standard IC method, in this paper, a revised IC balancing methodology for rotating machines is proposed. In this sense, a preprocessing stage is applied to access the uncertainties affecting the rotating machine. In this sense, measurement data sets evaluated under the fuzzy logic approach are used. Thus, the rotor vibration responses measured over a long period are considered by means of a fuzzy transformation (defining unbalance fuzzy sets). The unbalance condition of the rotating machine is determined through a defuzzification process. This unbalance condition is then introduced in the IC method algorithm aiming at obtaining correction weights and associated angular positions that increase the balancing robustness as compared with the classical approach. Numerical and experimental studies are used to evaluate the effectiveness of the proposed methodology. The obtained results illustrate the capacity to increase the balancing overall robustness.

3-D reconstruction and analysis of mammalian mitotic spindle structure

1992 ◽  
Vol 50 (1) ◽  
pp. 578-579
Author(s):  
Kent McDonald ◽  
David Mastronarde ◽  
Rubai Ding ◽  
Eileen O'Toole ◽  
J. Richard McIntosh
Keyword(s):  
Cross Sections ◽  
Mitotic Spindle ◽  
Experimental Studies ◽  
Video Camera ◽  
Three Dimensions ◽  
Mitotic Spindles ◽  
Black And White ◽  
Reconstruction Methods ◽  
Spindle Structure ◽  
Tissue Culture Line

Mammalian spindles are generally large and may contain over a thousand microtubules (MTs). For this reason they are difficult to reconstruct in three dimensions and many researchers have chosen to study the smaller and simpler spindles of lower eukaryotes. Nevertheless, the mammalian spindle is used for many experimental studies and it would be useful to know its detailed structure.We have been using serial cross sections and computer reconstruction methods to analyze MT distributions in mitotic spindles of PtK cells, a mammalian tissue culture line. Images from EM negatives are digtized on a light box by a Dage MTI video camera containing a black and white Saticon tube. The signal is digitized by a Parallax 1280 graphics device in a MicroVax III computer. Microtubules are digitized at a magnification such that each is 10-12 pixels in diameter.

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