Vibration Characteristics Diagnosis and Estimation of Fault Sizes in Rolling Contact Bearings: A Model Based Approach

2021 ◽  
pp. 1-40
Author(s):  
Imran Jamadar
Keyword(s):  
Experimental Data ◽  
Rolling Contact ◽  
Experimental Methodology ◽  
Vibration Acceleration ◽  
Data Set ◽  
Outer Race ◽  
Model Based ◽  
Computational Performance ◽  
Acceleration Amplitude ◽  
Inner Race

Abstract A novel model based technique is presented in this paper for the estimation of the fault size in different components of rolling contact bearings. A detailed dimensional analysis of the problem is carried out and experimental methodology using Box-Behnken design is applied to generate the experimental data set. First, analysis of the vibration acceleration amplitude at the fault frequency, its dependence on the bearing operating and fault parameters using the obtained vibration data set is carried out by statistical analysis of variance. Numerical equations are developed then using the experimental data set for the correlation of the vibration acceleration amplitude in frequency domain with the fault sizes based on the developed dimensionless terms. A hybrid Back propagation neural network integrating genetic algorithms is also developed so as to check the computational performance of the developed model equations. Validation of the proposed method is carried experimentally also for three seeded defect sizes on outer race, inner race and rolling element. The maximum model accuracy observed is for inner race defect case with predictive accuracy of 99.44 percentage and for the roller defect case it is 98.77 percentage. The deviance observed for the model predictive performance is maximum for outer race defect case with least accuracy of 90.47 percentage amongst all.

Turbocharger Performance Maps Building Using a Hot Gas Test Stand

2008 ◽  
Author(s):  
Giuliano Gardolinski Venson ◽  
Jose´ Eduardo Mautone Barros
Keyword(s):  
Experimental Data ◽  
Empirical Model ◽  
Quadratic Equation ◽  
Test Stand ◽  
Experimental Methodology ◽  
Maximum Deviation ◽  
Gas Generator ◽  
Hot Gas ◽  
Model Based ◽  
Semi Empirical

This work presents the experimental methodology used in turbochargers tests using a hot gas test stand. The test consists in recording the characteristic curves of the turbochargers, known as flow maps or performance maps. A tubular combustion chamber, designed to operate burning gaseous fuels, is used to drive the set. By using a hot gas generator it’s possible to simulate the real operational condition of the turbine. The experimental configuration allows reproducing the self-sustained turbocharger operation. The test stand instrumentation is based on virtual instrumentation, where acquisition of the sensors and control are made by computer. For the performance maps obtainment, the experimental data are treated through an empirical model based in a quadratic equation involving two variables, mass flow rate and rotational speed. The results present the performance and efficiency maps for the APL-240 Master Power turbocharger, used in commercial heavy trucks. With the results is made a comparison between the experimental maps with the maps gotten through a semi-empirical model based in modified Euler equation. The maximum deviation for compressor and turbine semi-empirical pressure ratios are respectively 8% and 14% in relation to the experimental data.

scholarly journals GPU acceleration of a model-based iterative method for Digital Breast Tomosynthesis

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. Cavicchioli ◽  
J. Cheng Hu ◽  
E. Loli Piccolomini ◽  
E. Morotti ◽  
L. Zanni
Keyword(s):  
Graphics Processing Unit ◽  
Digital Breast Tomosynthesis ◽  
Projection Algorithm ◽  
Processing Unit ◽  
Data Set ◽  
Breast Tomosynthesis ◽  
Model Based ◽  
Computational Performance ◽  
Gradient Based ◽  
Time Required

AbstractDigital Breast Tomosynthesis (DBT) is a modern 3D Computed Tomography X-ray technique for the early detection of breast tumors, which is receiving growing interest in the medical and scientific community. Since DBT performs incomplete sampling of data, the image reconstruction approaches based on iterative methods are preferable to the classical analytic techniques, such as the Filtered Back Projection algorithm, providing fewer artifacts. In this work, we consider a Model-Based Iterative Reconstruction (MBIR) method well suited to describe the DBT data acquisition process and to include prior information on the reconstructed image. We propose a gradient-based solver named Scaled Gradient Projection (SGP) for the solution of the constrained optimization problem arising in the considered MBIR method. Even if the SGP algorithm exhibits fast convergence, the time required on a serial computer for the reconstruction of a real DBT data set is too long for the clinical needs. In this paper we propose a parallel SGP version designed to perform the most expensive computations of each iteration on Graphics Processing Unit (GPU). We apply the proposed parallel approach on three different GPU boards, with computational performance comparable with that of the boards usually installed in commercial DBT systems. The numerical results show that the proposed GPU-based MBIR method provides accurate reconstructions in a time suitable for clinical trials.

A Multiphase Computational Study of Oil-Air Flow Within the Bearing Sector of Aeroengines

2015 ◽  
Author(s):  
Akinola A. Adeniyi ◽  
Hervé P. Morvan ◽  
Kathy A. Simmons
Keyword(s):  
Boundary Conditions ◽  
Computational Study ◽  
Roller Bearing ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Contact Friction ◽  
Outer Race ◽  
Roller Bearings ◽  
Rolling Elements ◽  
Inner Race

The bearing chamber of an aeroengine houses roller bearings and other structural parts. The spatial limitation, high operational speeds of the HP shaft and the proximity to the combustion chamber can make the operating conditions of the bearing chamber challenging. A roller bearing consists of an inner race, an outer race and a cage constraining a number of rolling elements. In the aeroengine application, oil is introduced into the bearing chamber via the inner race regions of the bearing into the rolling elements interstices. This provides lubrication for the roller bearings. The source of heat in the bearing chamber is mainly from rolling contact friction and the high temperature of combustion. Cooling results from the oil transport within the bearing chamber and thus an efficient transport of oil is critical to maintaining the integrity of the entire structure. The bearing chamber contains the oil which is eventually scavenged and recycled for recirculation. Experiments have been conducted over the years on bearing chamber flows but often simplified to create the best emulation of the real aeroengine. The complexity of the bearing chamber structure is also challenging for experimental measurements of the oil characteristic in the roller bearing elements and the bearing chamber compartment. Previous experiments have shown that the oil continuum breaks up in the bearing chamber compartment but it is not quantitatively clear how and what parameters affect these. Previous simulation attempt of bearing chamber, also, have been limited by the boundary conditions for the oil. This work presents a computational fluid dynamics (CFD) transient simulation of flow in the bearing sector in an attempt create boundary conditions for such models. The current results show that the oil emerges in the form of droplets into the bearing chamber compartment with speed of the order of 10% of the shaft rotation.

Antifriction Bearings Damage Analysis Using Experimental Data Based Models

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
R. G. Desavale ◽  
R. Venkatachalam ◽  
S. P. Chavan
Keyword(s):  
Experimental Data ◽  
Signal Analysis ◽  
Vibration Signal ◽  
Damage Analysis ◽  
Maintenance Strategies ◽  
Outer Race ◽  
Analysis Techniques ◽  
Catastrophic Failures ◽  
Original Contribution ◽  
Inner Race

Diagnosis of antifriction bearings is usually performed by means of vibration signals measured by accelerometers placed in the proximity of the bearing under investigation. The aim is to monitor the integrity of the bearing components, in order to avoid catastrophic failures, or to implement condition based maintenance strategies. In particular, the trend in this field is to combine in a simple theory the different signal-enhancement and signal-analysis techniques. The experimental data based model (EDBM) has been pointed out as a key tool that is able to highlight the effect of possible damage in one of the bearing components within the vibration signal. This paper presents the application of the EDBM technique to signals collected on a test-rig, and be able to test damaged fibrizer roller bearings in different working conditions. The effectiveness of the technique has been tested by comparing the results of one undamaged bearing with three bearings artificially damaged in different locations, namely on the inner race, outer race, and rollers. Since EDBM performances are dependent on the filter length, the most suitable value of this parameter is defined on the basis of both the application and measured signals. This paper represents an original contribution of the paper.

Determination of Rolling Contact Stress Distribution by X-ray Diffraction

1989 ◽  
Vol 33 ◽  
pp. 341-352
Author(s):  
David L. Milan
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Contact Stress ◽  
Rolling Direction ◽  
Roller Bearing ◽  
Rolling Contact ◽  
Outer Race ◽  
Contact Stress Distribution ◽  
Inner Race

AbstractAn investigation was conducted of the potential for detection of the contact stress distribution in tapered roller bearing components made of carburized steel. Various raceway stress distributions were created by control of the profile and alignment of the rolling surfaces. Determination of residual stress in the rolling direction and peak breadth were made using a multiple tilt sin2 ψ technique. The measurements were made at the surface and at depths below the surface. It was found that the distribution of residual stress and peak breadth perpendicular to the rolling direction in the layers below the surface of the inner race correlated highly with the imposed contact stress distribution. The correlation was less in the case of the outer race. The residual stress distribution measured on the surface of the inner race was observed to be inversely proportional to the contact stress distribution.

scholarly journals Autonomous Fingerprinting and Large Experimental Data Set for Visible Light Positioning

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3256
Author(s):  
Tyrel Glass ◽  
Fakhrul Alam ◽  
Mathew Legg ◽  
Frazer Noble
Keyword(s):  
Experimental Data ◽  
Visible Light ◽  
Nearest Neighbor ◽  
Channel Model ◽  
Ground Truth ◽  
Small Data ◽  
Large Set ◽  
K Nearest Neighbor ◽  
Data Set ◽  
Model Based

This paper presents an autonomous method of collecting data for Visible Light Positioning (VLP) and a comprehensive investigation of VLP using a large set of experimental data. Received Signal Strength (RSS) data are efficiently collected using a novel method that utilizes consumer grade Virtual Reality (VR) tracking for accurate ground truth recording. An investigation into the accuracy of the ground truth system showed median and 90th percentile errors of 4.24 and 7.35 mm, respectively. Co-locating a VR tracker with a photodiode-equipped VLP receiver on a mobile robotic platform allows fingerprinting on a scale and accuracy that has not been possible with traditional manual collection methods. RSS data at 7344 locations within a 6.3 × 6.9 m test space fitted with 11 VLP luminaires is collected and has been made available for researchers. The quality and the volume of the data allow for a robust study of Machine Learning (ML)- and channel model-based positioning utilizing visible light. Among the ML-based techniques, ridge regression is found to be the most accurate, outperforming Weighted k Nearest Neighbor, Multilayer Perceptron, and random forest, among others. Model-based positioning is more accurate than ML techniques when a small data set is available for calibration and training. However, if a large data set is available for training, ML-based positioning outperforms its model-based counterparts in terms of localization accuracy.

Nonlinear Mechanics of Rolling Contacts With Surface Defects

2010 ◽  
Author(s):  
Mohsen Nakhaeinejad ◽  
Jaewon Choi ◽  
Michael D. Bryant
Keyword(s):  
Surface Defects ◽  
Nonlinear Behavior ◽  
Rolling Contact ◽  
Rolling Element Bearing ◽  
Rolling Element Bearings ◽  
Detailed Model ◽  
Outer Race ◽  
Model Based ◽  
Rolling Contacts ◽  
Rolling Element

Nonlinear behavior of force and displacements in rolling contacts with the presence of surface defects are studied. Model-based fault assessments in rolling element bearings and gears require detailed modeling and dynamics of faults. A detailed model of rolling element bearings with direct correspondence between parameters of the model and physical components is developed. The model incorporates dynamics of faults, nonlinear contacts, slips and surface separations. Mechanics of contacts with inner race faults (IRF), ball faults (BF), and outer race faults (ORF) are studied using the developed model. Contacts force, displacement and impulse signals are studied for different size and types of surface defects. It is shown that impulse signals contain useful information about the severity of surface defects in rolling element bearing. Results provide model-based diagnostics a deep knowledge of rolling contact mechanics with surface defects to be used for fault assessments.

EXPERIMENTAL DATA SET NO. 24: PHASE DISTRIBUTION IN BUBBLY FLOW

1992 ◽  
Vol 6 (1-4) ◽  
pp. 257-301 ◽  
Author(s):  
Akimi Serizawa ◽  
Isao Kataoka ◽  
Itaru Michiyoshi
Keyword(s):  
Experimental Data ◽  
Phase Distribution ◽  
Bubbly Flow ◽  
Data Set
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