Damage Equivalent Test Methodologies as Design Elements for Journal Bearing Systems

Summer, Florian; Bergmann, Philipp; Grün, Florian

doi:10.3390/lubricants5040047

Cited by 14 publications

(7 citation statements)

References 21 publications

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“…Some useful recommendations for future scientific studies in this area are also given in this paper. Paper [7] is devoted to experimental studies of sliding support systems. Two laboratory test procedures are presented and their ability to visualize certain bearing performance parameters is emphasized.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Revealing deformation of segments and their supports in a hydrostatic segmental bearing

Nazin

2021

EEJET

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At present, there are theoretical and experimental studies of such bearings without taking into account the elastic deformation of the bearing segments. The rotor bearings of powerful turbines at nuclear power plants are subjected to loads as high as tens of tons. One of the important issues in designing segmental bearings operating under these conditions consists in taking into account elastic deformations of the segments. A schematic diagram of a segmental hydrostatic bearing was presented and the principle of its operation was described. When determining the deformation of spherical support, a formula of change in volume of a solid steel ball subjected to uniform pressure was applied. To determine the segment deformation in the axial direction, differential equation of bending of the strip beam as the initial one. The basic equation of deformation of rods with a curved axis acting in the plane of curvature was taken as a starting point of determining the segment deformation in the circumferential direction. It was found in the studies that the maximum deformation of the segment is 4.5 % of radial clearance at a feed pressure of 5 MPa and can affect the bearing characteristics. A substantially nonlinear character of deformations along the segment axis was revealed. It was found that the pressure of the working fluid significantly affects the segment thickness. With an increase in feeding pressure from 1 MPa to 10 MPa, the thickness of the steel segment increased more than 2 times and the thickness of the bronze segment increased more than 3 times. It was established that the pressure of the working fluid exceeding 10 MPa substantially affects the deformation of the spherical support and the bearing clearance. The study results will make it possible to determine more accurately the main characteristics of the segmental bearing and design it more efficiently.

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Section: Literature Review and Problem Statementmentioning

confidence: 99%

Revealing deformation of segments and their supports in a hydrostatic segmental bearing

Nazin

2021

EEJET

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“…To guarantee reproducible hydrodynamic conditions, the heat control uses a thermo couple, measuring the oil temperature in the reservoir (accuracy < 1°K). The combination of free rotation of the bearing adapter, supported by a load cell on the main frame, enables a sensitive friction force measurement and subsequently a friction coefficient measurement with a relative error of ≈ 2.3% (details can be found in [9]). A pre-and post-test measurement of bearing shell weight and thickness is used for determining bearing wear.…”

Section: The Physical Simulation Modelmentioning

confidence: 99%

“…In these equations, ∆p is the applied pressure gradient for the pressure flow calculation p Inlet − p Outlet , ∆x is the distance between inlet and outlet, and b is the width of the micro model. The flow rate of the rough lubricating gap is the output of the CFD simulation and can be determined by Equation (9). It calculates the flow through a surface A cross , which lies across the flow direction, using the velocity vectors u from the CFD calculation together with normal vectors n of A cross .…”

Section: The Virtual Simulation Strategymentioning

confidence: 99%

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Assessment of Shaft Surface Structures on the Tribological Behavior of Journal Bearings by Physical and Virtual Simulation

et al. 2020

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Optimizing the surface topography of cast iron crankshafts offers the opportunity to use this material as an alternative to steel in high-performance combustion engines. In the past, this was not possible due to the higher wear on bearing shells and the higher friction losses in relation to forged steel shafts. In order to find an optimized shaft micro topography, the friction and wear behavior of steel and cast iron shafts with different surface treatments were compared to each other, using a combined physical (experimental) and a virtual (computational) simulation approach. The experiments were carried out with a rotary tribometer using a journal bearing test configuration with the possibility to test real-life bearing shells and shaft specimens, manufactured from real-life crankshafts. In the experiments, a polished steel shaft with low bearing wear was effective. The optimization of cast iron crankshafts by a novel surface treatment showed a significant reduction of bearing wear in relation to the classical surface finishing procedures of cast iron shafts. A computational simulation approach, considering the real-life micro topography by using the Navier–Stokes equations for the calculation of micro hydrodynamics, supports the assessment of fluid friction. The virtual simulation shows, in accordance to the experimental results, only a minor influence of the investigated shaft topographies on the fluid friction. Further optimization of shaft surfaces for journal bearing systems seems possible only by the usage of patterned micro topographies.

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“…Bearing segment test methodology: (a) Set-up and test area/skills; (b) Implementation of the set-up on a tribometer test rig TE92. CP = electrical resistance measurement[22].…”

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confidence: 99%

Lubrication Regime Classification of Hydrodynamic Journal Bearings by Machine Learning Using Torque Data

2018

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Hydrodynamic journal bearings are used within a wide range of machines, such as combustion engines, gas turbines, or wind turbines. For a safe operation, awareness of the lubrication regime, in which the bearing is currently operating, is of great importance. In the current study, highspeed data signals of a torque sensor, sampled with a frequency of 1000 hz in a time range of 2.5 s, obtained on a journal bearing test-rig under various operating conditions, are used to train machine learning models, such as neural networks and logistic regression. Results indicate that a fast Fourier transform (fft) of the highspeed torque signals enables accurate predictions of lubrication regimes. The trained models are analysed in order to identify distinctive frequencies for the respective lubrication regime.

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Damage Equivalent Test Methodologies as Design Elements for Journal Bearing Systems

Cited by 14 publications

References 21 publications

Revealing deformation of segments and their supports in a hydrostatic segmental bearing

Revealing deformation of segments and their supports in a hydrostatic segmental bearing

Assessment of Shaft Surface Structures on the Tribological Behavior of Journal Bearings by Physical and Virtual Simulation

Lubrication Regime Classification of Hydrodynamic Journal Bearings by Machine Learning Using Torque Data

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