Discovering Irregular Diagnostic Proper Orthogonal Decomposition Signatures in Healthy Marine Ball Bearings

2012 ◽  
Author(s):  
Ioannis T. Georgiou ◽  
Nikolaos Kintzios
Keyword(s):  
Spatial Distribution ◽  
Ball Bearing ◽  
Flexible Structures ◽  
Ball Bearings ◽  
Radial Acceleration ◽  
Outer Race ◽  
Structural Health ◽  
Proper Orthogonal ◽  
The Impact ◽  
Acceleration Signals

Presented is a structural health condition diagnosis based on optimal space-time decompositions of ensembles of acceleration signals developed in the complex physical domain of marine ball bearings when interrogated by a set of diagnostic impulsive forces. Ensembles of diagnostic forces and ensembles of collocated responses acceleration signals are decomposed into proper orthogonal modes. Typical inner and ensembles of nondestructive impact diagnostic forces covering three times the inner and outer races are strongly dominated by a single POD mode with uniform spatial distribution and a sharp pulse time modulation. There exist high order modes with very small amount of energy. This indicates that the impact response of the suspended ball bearing depends slightly on the impact location. Diametrically opposite, the typical ensemble of radial acceleration signals collected at a point on the outer race has a very broad POD energy spectrum. All POD modes have energy fractions of the same order and irregular (no periodic) space modulations. Despite this spatial irregularity, all POD spatial modulations have astonishingly common statistical properties: nearly zero mean values, and nearly identical standard deviations at the value level of the uniform spatial distribution of the dominant POD mode of the ensembles of diagnostic forces. The result is that the healthy ball bearing spreads nearly evenly the energy of collocated acceleration signals to a large number of POD modes. The analysis aims at gaining a basic understanding of the behavior of collocated acceleration signals developed in the complex domains of multi-body flexible structures with applications in structural health monitoring of marine-aeronautical machinery critical elements such as propellers, bearings, brakes, clutches and gearboxes.

Detection of Coherence in Collocated Experimental Acceleration Signals in a Flexible Aluminum Multi-Beam Structure

2011 ◽  
Author(s):  
Ioannis T. Georgiou
Keyword(s):  
State Of The Art ◽  
Normal Modes ◽  
Piezoelectric Sensors ◽  
Beam Structure ◽  
Original Result ◽  
Unit Space ◽  
Modes Of Vibration ◽  
Proper Orthogonal ◽  
The Impact ◽  
Acceleration Signals

The present work concerns the study of the experimental Proper Orthogonal Decomposition (POD) modes of three simultaneously acquired ensembles of collocated impulse-induced acceleration signals in a complex multi-beam aluminum structure. The impact-induced locally transverse acceleration of a three-beam structure is measured simultaneously at three fixed points with state-of-the-art piezoelectric sensors. Each ensemble of collocated databases is processed by the POD Transform to find out that it is underlined by strong coherence in space and time manifested by a small number of POD modes. It is found that the unit space modulations of the first-the dominant-POD modes of the three databases of experimental acceleration signals form an orthonormal set. The same is true for their companion unit time modulations. This original result leads to the identification of three normal modes of vibration for the complex beam structure.

Investigation of Dynamic Processes in Ball Bearings with Defects

2013 ◽  
Vol 198 ◽  
pp. 651-656 ◽  
Author(s):  
Marijonas Bogdevičius ◽  
Viktor Skrickij
Keyword(s):  
Mathematical Model ◽  
Ball Bearing ◽  
Dynamic Processes ◽  
Experimental Investigations ◽  
Ball Bearings ◽  
Outer Race ◽  
Rolling Element ◽  
Inner Race

The paper considers the dynamics of ball bearings with defects. A mathematical model of a ball bearing with defects is offered. The performed theoretical and experimental investigations of ball bearings with defects are described. Five cases of various defects are investigated, including the defective outer race, the defective inner race, the defective rolling element, the defective inner and outer races, the rolling element and a separator, the worn-out ball bearing.

scholarly journals Performance of 75-Millimeter Bore Arched Outer-Race Ball Bearings

1977 ◽  
Vol 99 (3) ◽  
pp. 346-352 ◽  
Author(s):  
H. H. Coe ◽  
B. J. Hamrock
Keyword(s):  
Experimental Data ◽  
Computer Program ◽  
Analytical Study ◽  
Ball Bearing ◽  
Ball Bearings ◽  
Shaft Speed ◽  
Operating Characteristics ◽  
Outer Race ◽  
Deep Groove ◽  
Deep Groove Ball Bearing

An investigation was performed to determine the operating characteristics of 75-mm bore, arched outer-race bearings, and to compare the data with those for a similar, but conventional, deep groove ball bearing. Further, results of an analytical study, made using a computer program developed previously, were compared with the experimental data. Bearings were tested up to 28,000 rpm shaft speed with a load of 2,200 N (500 lb). The amount of arching was 0.13, 0.25, and 0.51 mm (0.005, 0.010, and 0.020 in.). All bearings operated satisfactorily. The outer-race temperatures and the torques, however, were consistently higher for the arched bearings than for the conventional bearings.

Numerical investigation of the oil–air distribution inside ball bearings with under-race lubrication

2021 ◽  
pp. 135065012110105
Author(s):  
Le Jiang ◽  
Yaguo Lyu ◽  
Wenjun Gao ◽  
Pengfei Zhu ◽  
Zhenxia Liu
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Volume Fraction ◽  
Volume Flow Rate ◽  
Ball Bearings ◽  
Outer Race ◽  
Rotating Speed ◽  
Oil Distribution ◽  
Hole Configuration ◽  
Inner Race

Oil distribution inside the under-race lubricated bearing is crucial for lubrication and cooling of high-speed ball bearings. An under-race lubricated ball bearing is modeled to numerically investigate the effects of operating parameters and feed hole configuration on the distribution behavior of lubricant oil. The results of the numerical simulation indicate that the average oil volume fraction changes with a convex trend as the outer race rotating speed increases, while it changes monotonically with the inner race rotating speed, oil volume flow rate, and oil temperature. The extent of oil spreading on the outer race, cage, ball, and inner race decreases successively. Optimizing the feed hole configuration according to the average oil volume fraction is helpful to achieve precise lubrication of the under-race lubricated ball bearing.

scholarly journals Wear and Friction of Tungsten-based Coatings of Steel under Sliding Contact

2018 ◽  
Author(s):  
Matthew Marko
Keyword(s):  
Ball Bearing ◽  
Sliding Contact ◽  
Ball Bearings ◽  
Grease Lubrication ◽  
Wear And Friction ◽  
The Coefficient Of Friction ◽  
Tungsten Surface ◽  
Steel Surfaces ◽  
The Impact ◽  
Ball Test

An investigation was made to determine the effects of tungsten surface coating on the coefficient of friction of sliding contact between lubricated steel surfaces. The four-ball test was modified, using a tungsten carbide ball bearing in the spindle to cause sliding contact onto three hard steel ball bearings coated with tungsten disulfide lamellar dry lubricant coating, with a coating of grease lubrication applied to the ball bearings. The coatings, loads, speed, and grease level was varied to best understand the impact of different conditions to the friction coefficient.

scholarly journals Friction of Tungsten-Based Coatings of Steel under Sliding Contact

Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 14 ◽  
Author(s):  
Matthew Marko
Keyword(s):  
Surface Coating ◽  
Ball Bearing ◽  
Sliding Contact ◽  
Ball Bearings ◽  
Grease Lubrication ◽  
The Coefficient Of Friction ◽  
Tungsten Surface ◽  
Steel Surfaces ◽  
The Impact ◽  
Ball Test

An investigation was made to determine the effects of tungsten surface coating on the coefficient of friction of sliding contact between lubricated steel surfaces. The four-ball test was modified, using a tungsten carbide ball bearing in the spindle to cause sliding contact onto three hard steel ball bearings coated with tungsten disulfide lamellar dry lubricant coating, with a coating of grease lubrication applied to the ball bearings. The coatings, loads, speed, and grease level were varied to best understand the impact of different conditions on the friction coefficient.

Load–Displacement Relationship of a Ball Bearing With Axial, Radial, and Angular Displacements for Both the Inner and Outer Rings

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Hiroyuki Ohta ◽  
Tomoya Sakaguchi ◽  
Masaharu Uchiumi
Keyword(s):  
Radial Displacement ◽  
Ball Bearing ◽  
Angular Displacement ◽  
Axial Displacement ◽  
Outer Ring ◽  
Ball Bearings ◽  
Outer Race ◽  
Load Displacement ◽  
Angular Displacements ◽  
Relationship Of

This paper deals with the load–displacement relationship of a ball bearing with axial, radial, and angular displacements for both the inner and outer rings. First, the expressions for the load–displacement relationship of ball bearings with any number of balls under the combined axial, radial, and moment loads were presented by using a system in which both the inner and outer rings are allowed to move in the axial, radial, and angular directions. Second, the presented expressions were compared with Jones' expressions (which are typical conventional expressions for the load–displacement relationship), then the range of application of Jones's expressions were elucidated. Third, the relative axial displacement, the relative radial displacement, and the relative angular displacement of a miniature ball bearing type 692 under the combined axial, radial, and moment loads were calculated. Finally, it was shown that the relative angular displacement in the case with no inner ring angular displacement is Ri/Ro times the relative angular displacement in the case with no outer ring angular displacement, in which Ri and Ro are the radii of the inner and outer race curvature center loci.

scholarly journals Evaluation of Electron-Beam Welded Hollow Balls for High-Speed Ball Bearings

1971 ◽  
Vol 93 (1) ◽  
pp. 47-55 ◽  
Author(s):  
Harold H. Coe ◽  
Richard J. Parker ◽  
Herbert W. Scibbe
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Ball Bearing ◽  
Similar Data ◽  
Ball Bearings ◽  
Outer Race ◽  
Rolling Element ◽  
Solid Ball ◽  
Steel Balls ◽  
Weld Area

An experimental investigation was performed with two series (115 and 215) of 75 mm bore ball bearings using hollow balls as the rolling elements. The bearings were tested at 500 and 1000 pounds thrust loads at shaft speeds up to 24000 rpm. The 115 series bearings with 1/2-in. SAE 52100 steel balls showed very little difference in torque, outer-race temperature, or rolling-element fatigue life when compared to similar data for a solid ball bearing. The 215 series bearings with 11/16-in. AISI M-50 steel balls showed only slight differences in torque and outer-race temperature but a very significant decrease in rolling-element fatigue life compared to a solid ball bearing. The balls failed in flexure fatigue, due to a stress concentration in the weld area.

Temperature Rise Prediction of Oil-Air Lubricated Angular Contact Ball Bearings Using Artificial Neural Network

2019 ◽  
Vol 12 (3) ◽  
pp. 248-261
Author(s):  
Baomin Wang ◽  
Xiao Chang
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Temperature Rise ◽  
High Speed ◽  
Ball Bearing ◽  
Influence Factors ◽  
Ball Bearings ◽  
Ann Model ◽  
Angular Contact Ball Bearing ◽  
Artificial Neural

Background: Angular contact ball bearing is an important component of many high-speed rotating mechanical systems. Oil-air lubrication makes it possible for angular contact ball bearing to operate at high speed. So the lubrication state of angular contact ball bearing directly affects the performance of the mechanical systems. However, as bearing rotation speed increases, the temperature rise is still the dominant limiting factor for improving the performance and service life of angular contact ball bearings. Therefore, it is very necessary to predict the temperature rise of angular contact ball bearings lubricated with oil-air. Objective: The purpose of this study is to provide an overview of temperature calculation of bearing from many studies and patents, and propose a new prediction method for temperature rise of angular contact ball bearing. Methods: Based on the artificial neural network and genetic algorithm, a new prediction methodology for bearings temperature rise was proposed which capitalizes on the notion that the temperature rise of oil-air lubricated angular contact ball bearing is generally coupling. The influence factors of temperature rise in high-speed angular contact ball bearings were analyzed through grey relational analysis, and the key influence factors are determined. Combined with Genetic Algorithm (GA), the Artificial Neural Network (ANN) model based on these key influence factors was built up, two groups of experimental data were used to train and validate the ANN model. Results: Compared with the ANN model, the ANN-GA model has shorter training time, higher accuracy and better stability, the output of ANN-GA model shows a good agreement with the experimental data, above 92% of bearing temperature rise under varying conditions can be predicted using the ANNGA model. Conclusion: A new method was proposed to predict the temperature rise of oil-air lubricated angular contact ball bearings based on the artificial neural network and genetic algorithm. The results show that the prediction model has good accuracy, stability and robustness.

Modelling Agricultural Controls for Flooding and Soil Erosion

2018 ◽  
pp. 776-796
Author(s):  
Roger Moussa ◽  
Bruno Cheviron
Keyword(s):  
Spatial Distribution ◽  
Model Structure ◽  
Land Uses ◽  
Research Challenges ◽  
Water And Sediment ◽  
Flow Processes ◽  
Cultivation Practices ◽  
Modelling Strategies ◽  
The Impact ◽  
Significant Factors

Floods are the highest-impact natural disasters. In agricultural basins, anthropogenic features are significant factors in controlling flood and erosion. A hydrological-hydraulic-erosion diagnosis is necessary in order to choose the most relevant action zones and to make recommendations for alternative land uses and cultivation practices in order to control and reduce floods and erosion. This chapter first aims to provide an overview of the flow processes represented in the various possible choices of model structure and refinement. It then focuses on the impact of the spatial distribution and temporal variation of hydrological soil properties in farmed basins, representing their effects on the modelled water and sediment flows. Research challenges and leads are then tackled, trying to identify the conditions in which sufficient adequacy exists between site data and modelling strategies.

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