The Effect of the EHD Pressure Spike on Rolling Bearing Fatigue

1987 ◽  
Vol 109 (3) ◽  
pp. 444-450 ◽  
Author(s):  
L. Houpert ◽  
E. Ioannides ◽  
J. C. Kuypers ◽  
J. Tripp
Keyword(s):  
Pressure Distribution ◽  
High Stress ◽  
Surface Damage ◽  
Rolling Bearing ◽  
Shear Stresses ◽  
Stress Concentrations ◽  
Surface Layers ◽  
Rolling Bearings ◽  
Life Model ◽  
Pressure Spike

A recently proposed fatigue life model for rolling bearings has been applied to the study of lifetime reduction under conditions conducive to microspalling. The presence of a spike in the EHD pressure distribution produces large shear stresses localized very close to the surface which may account for early failure. This paper describes a parametric study of the effect of such spikes. Accurate stress fields in the volume are calculated for simulated pressure spikes of different height, width and position relative to a Hertzian pressure distribution, as well as for different lubricant traction coefficients and film thicknesses. Despite the high stress concentrations in the surface layers, reductions in life predicted by the model are modest. Typically, the pressure spike may halve the life, with the implication that subsurface fatigue still dominates. In corroboration of this prediction, preliminary experimental work designed to reproduce microspalling conditions shows that microindents due to overrolling particles are a much more common form of surface damage than microspalling.

DETERMINING THE RESOURCE OF THE OUTER RING OF A ROLLING BEARING BASED ON SIGNAL REGISTRATION AND SIMULATION OF THE TIME DEPENDENCE OF ACOUSTIC EMISSION PARAMETERS

2020 ◽  
pp. 26-34
Author(s):  
V. V. Nosov ◽  
I. A. Pavlenko ◽  
A. P. Artyushchenko ◽  
E. V. Grigoriev
Keyword(s):  
Acoustic Emission ◽  
Time Dependence ◽  
Experimental Studies ◽  
Surface Damage ◽  
Rolling Bearing ◽  
Diagnostic Value ◽  
Outer Ring ◽  
Rolling Bearings ◽  
Useful Signal ◽  
Informative Signals

Traditionally, the problem of monitoring the condition of rolling bearings can be solved based on registration of control signals that occur when the bearing performs a kinematic function due to contact of surface damage which is accumulated and caused by the processes of friction, impact, heat generation, contact electrical interaction, generation of elastic vibrations from them, etc. Relative to the bearing function of bearings, the diagnostic value of such signals is quite low, since they depend on many factors that are not related to resource-determining processes and play a destabilizing role in establishing the connection between control parameters and condition. The solution of the problem must be carried out based on a systematic approach linking the control of the object with the main criterion of its performance. Since the cause of bearing failures is fatigue processes occurring in the material of their elements, the most promising methods are those based on the registration of signals associated with the restructuring of the structure and the accumulation of damage of the material, and in particular, the method of acoustic emission (AE) based on recording the phenomenon of waves of elastic radiation at loading. The development of the acoustic emission method for monitoring the state of rolling bearings is based on a multi-level model of the time dependence of AE parameters, and the control is based on the assessment of the intensity parameters of the resource-determining stage of uniform elastic fracture of representative structural elements of the material of the test object. AE informative signals are selected, and diagnostic parameters are determined at the interlevel transition from macro- to micro- and nano-level. The idea of the transitions is to select representative informative parameters and to trace the connection between them through AE strength indicators that can highlight a useful signal in conditions of high instability and heterogeneity of the accompanying processes. The experimental stup and the results of experimental studies of AE of rolling bearings with an artificially created defect on the surface of the outer ring are described, the results of control are compared with the results of the analysis of the stress-strain state around the created defect, the informative value of the concentration and kinetic index and the possibility of evaluating the resource based on it are shown.

Fault Diagnosis System of Rolling Bearing Based on Wavelet Analysis

2012 ◽  
Vol 166-169 ◽  
pp. 951-955 ◽  
Author(s):  
Li Na Wang ◽  
Hong Bo Wang ◽  
Yong Hui Cai ◽  
Shi Long Wang
Keyword(s):  
Fault Diagnosis ◽  
Wavelet Analysis ◽  
Friction Pair ◽  
Surface Damage ◽  
Rolling Bearing ◽  
Rolling Bearings ◽  
Diagnosis System ◽  
Stationary Signals ◽  
Diagnosis Method ◽  
Fault Diagnosis System

According to the characteristics of fault vibration of rolling bearing (non-stationary signals), a method of fault diagnosis based on wavelet analysis is put forward. In the method, the signals included faulty information of rolling bearing are decomposed and reconstructed by Matlab software, and by zoom frequency spectrum analysis, the fault information composition of the rolling bearings can be extracted effectively to determine the faulty type of the rolling bearings. Based on the above, an applicable fault diagnosis system for rolling bearing with surface damage in friction pair was developed. It has been proven by practice that the diagnosis method of system is surefire and its results are stable and reliable. Through being improved and expanded，the system can be applied to collect and analyze other vibration signals.

A New Fatigue Life Model for Rolling Bearings

1985 ◽  
Vol 107 (3) ◽  
pp. 367-377 ◽  
Author(s):  
E. Ioannides ◽  
T. A. Harris
Keyword(s):  
Fatigue Life ◽  
Rolling Bearing ◽  
Fatigue Tests ◽  
Operating Conditions ◽  
Rolling Bearings ◽  
Structural Fatigue ◽  
Probability Of Survival ◽  
Life Model ◽  
Life Predictions ◽  
Fatigue Criterion

This paper describes a novel model for the prediction of fatigue life in rolling bearings. Central to this model is the postulation of a statistical relationship between the probability of survival, the fatigue life, and a stress-related fatigue criterion level above a fatigue limit for an elementary volume of material in the bearing. Using this concept, the stress volume to fatigue and the fatigue life of the bearing can be calculated for different loads, material and operating conditions. Comparisons between experimentally obtained rolling bearing fatigue lives and lives predicted using this theory indicate its ability to account for phenomena hitherto excluded from fatigue life predictions. Furthermore, comparisons between experimentally obtained fatigue lives for other specimens used in structural fatigue tests and fatigue lives predicted using the new model show good agreement.

scholarly journals A novel method for diagnosing rolling bearing surface damage by electric impedance analysis

2022 ◽  
Author(s):  
Georg Martin ◽  
Florian Michael Becker ◽  
Eckhard Kirchner
Keyword(s):  
Impedance Analysis ◽  
Surface Damage ◽  
Time Domain Analysis ◽  
Rolling Bearing ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Rolling Bearings ◽  
Monitoring Method ◽  
Novel Method ◽  
Bearing Damage

This paper presents a novel condition monitoring method for rolling bearings, based on measuring the electric bearing impedance. The method can diagnose the presence of damage by frequency-domain analysis, and its extension along the raceway by time-domain analysis. The latter enables the assessment of the severity and the progression of bearing damage. A fatigue test shows that the occurrence of pittings in the bearing raceways causes characteristic peaks in the impedance signal, and that the duration of the peaks increases during damage progression. A second test series with artificial damage shows that the duration of the peaks depends on the bearing load and the length of the damage along the raceway and confirms the explanation hypothesis.

Efficiency of application of the phase-chronometric method and neurodiagnostics for monitoring the degradation of rolling bearings during operation

2020 ◽  
pp. 43-50
Author(s):  
A.S. Komshin ◽  
K.G. Potapov ◽  
V.I. Pronyakin ◽  
A.B. Syritskii
Keyword(s):  
Life Cycle ◽  
Wavelet Analysis ◽  
Metrological Support ◽  
Rolling Bearing ◽  
Technical Condition ◽  
Measurement Information ◽  
Rolling Bearings ◽  
Vibration Diagnostics ◽  
Bearing Life ◽  
Alternative Approach

The paper presents an alternative approach to metrological support and assessment of the technical condition of rolling bearings in operation. The analysis of existing approaches, including methods of vibration diagnostics, envelope analysis, wavelet analysis, etc. Considers the possibility of applying a phase-chronometric method for support on the basis of neurodiagnostics bearing life cycle on the basis of the unified format of measurement information. The possibility of diagnosing a rolling bearing when analyzing measurement information from the shaft and separator was evaluated.

The pressure spike mystery

2021 ◽  
pp. 135065012110330
Author(s):  
Yoshitsugu Kimura
Keyword(s):  
Pressure Distribution ◽  
Pressure Spike

An intuitive understanding of the pressure spike appearing in the elastohydrodynamic pressure distribution is presented. This comes from my personal memories of Professor Dowson from my first encounter with his book to my final conversation with him.

scholarly journals Behavior of Offshore Pile in Calcareous Sand—Case Study

2021 ◽  
Vol 9 (8) ◽  
pp. 839
Author(s):  
Tarek N. Salem ◽  
Nadia M. Elkhawas ◽  
Ahmed M. Elnady
Keyword(s):  
Load Capacity ◽  
High Stress ◽  
Embedment Depth ◽  
Shear Stresses ◽  
Northern Coast ◽  
Compression Tests ◽  
Calcareous Sand ◽  
Element Analysis ◽  
Mixing Ratios

The erosion of limestone and calcarenite ridges that existed parallel to the Mediterranean shoreline forms the calcareous sand (CS) formation at the surface layer of Egypt's northern coast. The CS is often combined with broken shells which are considered geotechnically problematic due to their possible crushability and relatively high compressibility. In this research, CS samples collected from a site along the northern coast of Egypt are studied to better understand its behavior under normal and shear stresses. Reconstituted CS specimens with different ratios of broken shells (BS) are also investigated to study the effect of BS ratios on the soil mixture strength behavior. The strength is evaluated using laboratory direct-shear and one-dimensional compression tests (oedometer test). The CS specimens are not exposed to significant crushability even under relatively high-stress levels. In addition, a 3D finite element analysis (FEA) is presented in this paper to study the degradation offshore pile capacity in CS having different percentages of BS. The stress–strain results using oedometer tests are compared with a numerical model, and it gave identical matching for most cases. The effects of pile diameter and embedment depth parameters are then studied for the case study on the northern coast. Three different mixing ratios of CS and BS have been used, CS + 10% BS, CS + 30% BS, and CS + 50% BS, which resulted in a decrease of the ultimate vertical compression pile load capacity by 8.8%, 15%, and 16%, respectively.

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