A Finite Element Investigation of a Bearing/Cartridge Interface for a Fretting Corrosion Study

1985 ◽  
Vol 107 (2) ◽  
pp. 157-163 ◽  
Author(s):  
R. J. Stover ◽  
H. H. Mabie ◽  
M. J. Furey
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Analytical Study ◽  
Experimental Tests ◽  
Tangential Direction ◽  
Rolling Element Bearings ◽  
Interface Conditions ◽  
Finite Element Technology ◽  
Rolling Element ◽  
Contact Pressures

The bearing/cartridge interfaces of a Ship Service Motor Generator Set (SSMG) were modeled by using finite element technology. The purpose of this analytical study was to verify the results of earlier experimental tests made on an actual SSMG unit. This research is part of a larger research project to examine the important parameters influencing the fretting of rolling element bearings. Models for the bearings at both ends of the unit were developed, and loads simulating the ball pass loads were applied to these models; the contact pressures, radial deformations, and relative displacements at the interface were calculated. The resulting data showed the interface conditions to be extremely complex with the contact pressures varying from zero to a maximum of 55.4 MPa (8030 psi) as the balls passed by. The maximum relative displacements occurred in the tangential direction (2.44 μm) and were independent of the axial boundary conditions.

Influence of Axial Excitations and of Boundary Conditions on the Parametric Instability of a Beam

1995 ◽  
Author(s):  
Régis Dufour ◽  
Alain Berlioz ◽  
Thomas Streule
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ritz Method ◽  
Parametric Instability ◽  
Experimental Tests ◽  
Time Varying ◽  
Periodic Force ◽  
Modal Reduction ◽  
Time Varying Parameter ◽  
The Stability

Abstract In this paper the stability of the lateral dynamic behavior of a pinned-pinned, clamped-pinned and clamped-clamped beam under axial periodic force or torque is studied. The time-varying parameter equations are derived using the Rayleigh-Ritz method. The stability analysis of the solution is based on Floquet’s theory and investigated in detail. The Rayleigh-Ritz results are compared to those of a finite element modal reduction. It shows that the lateral instabilities of the beam depend on the forcing frequency, the type of excitation and the boundary conditions. Several experimental tests enable the validation of the numerical results.

A NEW GEARBOX FAULT DIAGNOSIS METHOD BASED ON LUCY–RICHARDSON DECONVOLUTION

2015 ◽  
Vol 39 (3) ◽  
pp. 593-603
Author(s):  
Xinghui Zhang ◽  
Jianshe Kang ◽  
Hongzhi Teng ◽  
Jianmin Zhao
Keyword(s):  
Fault Diagnosis ◽  
Experimental Studies ◽  
Experimental Tests ◽  
Rolling Element Bearings ◽  
Envelope Analysis ◽  
Rolling Element ◽  
Negative Effect ◽  
Diagnosis Method ◽  
Good Identification ◽  
Incipient Fault Diagnosis

Gear and bearing faults are the main causes of gearbox failure. Till now, incipient fault diagnosis of these two components has been a problem and needs further research. In this context, it is found that Lucy–Richardson deconvolution (LRD) proved to be an excellent tool to enhance fault diagnosis in rolling element bearings and gears. LRD’s good identification capabilities of fault frequencies are presented which outperform envelope analysis. This is very critical for early fault diagnosis. The case studies were carried out to evaluate the effectiveness of the proposed method. The results of simulated and experimental studies show that LRD is efficient in alleviating the negative effect of noise and transmission path. The results of simulation and experimental tests demonstrated outperformance of LRD compared to classical envelope analysis for fault diagnosis in rolling element bearings and gears, especially when it is applied to the processing of signals with strong background noise.

scholarly journals Possible reasons for early artificial bone failure in biomechanical tests of ankle arthrodesis systems

2015 ◽  
Vol 1 (1) ◽  
pp. 507-509
Author(s):  
H. Martin ◽  
N. Gutteck ◽  
J.-B. Matthies ◽  
T. Hanke ◽  
G. Gradl ◽  
...  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Experimental Tests ◽  
Element Model ◽  
Ankle Arthrodesis ◽  
Artificial Bone ◽  
Basic Model ◽  
Simplified Finite Element Model ◽  
Biomechanical Tests ◽  
Horizontal Displacements

AbstractIn order to demonstrate the influence of the boundary conditions in experimental biomechanical investigations of arthrodesis implants two different models were investigated. As basic model, a simplified finite element model of the cortical bone was used in order to compare the stress values with (Model 1) and without (Model 2) allowing horizontal displacements of the load application point. The model without constraints of horizontal displacements showed considerably higher stress values at the point of failure. Moreover, this investigation shows that the boundary conditions (e.g. constraints) have to be carefully considered, since simplifications of the reality with experimental tests cannot always be avoided.

Fault Symptoms of Rolling Element Bearings Under Variable Operating Conditions: A Multi Domain Analysis

2012 ◽  
Author(s):  
P. Borghesani ◽  
R. Ricci ◽  
S. Chatterton ◽  
P. Pennacchi
Keyword(s):  
Digital Signal ◽  
Experimental Tests ◽  
Diagnostic Techniques ◽  
Operating Conditions ◽  
Small Scale ◽  
Rolling Element Bearings ◽  
Envelope Analysis ◽  
Spectral Kurtosis ◽  
Rolling Element ◽  
Variable Operating Conditions

Diagnostics of rolling element bearings have been traditionally developed for constant operating conditions, and sophisticated techniques, like Spectral Kurtosis or Envelope Analysis, have proven their effectiveness by means of experimental tests, mainly conducted in small-scale laboratory test-rigs. Algorithms have been developed for the digital signal processing of data collected at constant speed and bearing load, with a few exceptions, allowing only small fluctuations of these quantities. Owing to the spreading of condition based maintenance in many industrial fields, in the last years a need for more flexible algorithms emerged, asking for compatibility with highly variable operating conditions, such as acceleration/deceleration transients. This paper analyzes the problems related with significant speed and load variability, discussing in detail the effect that they have on bearing damage symptoms, and propose solutions to adapt existing algorithms to cope with this new challenge. In particular, the paper will i) discuss the implication of variable speed on the applicability of diagnostic techniques, ii) address quantitatively the effects of load on the characteristic frequencies of damaged bearings and iii) finally present a new approach for bearing diagnostics in variable conditions, based on envelope analysis. The research is based on experimental data obtained by using artificially damaged bearings installed on a full scale test-rig, equipped with actual train traction system and reproducing the operation on a real track, including all the environmental noise, owing to track irregularity and electrical disturbances of such a harsh application.

Condition monitoring studies on ball bearings considering solid contaminants in the lubricant

2010 ◽  
Vol 224 (8) ◽  
pp. 1727-1748 ◽  
Author(s):  
V Hariharan ◽  
P S S Srinivasan
Keyword(s):  
Particle Size ◽  
Condition Monitoring ◽  
Experimental Tests ◽  
Solid Particles ◽  
Contaminant Concentration ◽  
Ball Bearings ◽  
Rolling Element Bearings ◽  
Rolling Bearings ◽  
Rolling Element ◽  
Vibration Signatures

Rolling element bearings are common in any rotating machinery. They are subject to failure under continuous running. Therefore they have received a great deal of attention in the field of condition monitoring. In rolling element bearings, contamination of lubricant grease by solid particles is one of the several reasons for an early bearing failure. In this context, this article investigates the effect of contamination of lubricant by solid particles on the dynamic behaviour of rolling bearings. Silica powder at three concentration levels and different particle sizes was used to contaminate the lubricant. Experimental tests have been performed on the ball bearings lubricated with grease, and the trends in the amount of vibration affected by the contamination of the grease were determined. The contaminant concentration as well as the particle size is varied. Vibration signatures were analysed in terms of root mean square (RMS) values. From the results, some fruitful conclusions are made about the bearing performance. The effects of contaminant and the bearing vibration are studied for both good and defective bearings. The results show significant variation in the RMS velocity values on varying the contaminant concentration and particle size.

Parametric Instability of a Beam Due to Axial Excitations and to Boundary Conditions

1998 ◽  
Vol 120 (2) ◽  
pp. 461-467 ◽  
Author(s):  
R. Dufour ◽  
A. Berlioz
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ritz Method ◽  
Parametric Instability ◽  
Experimental Tests ◽  
Time Varying ◽  
Periodic Force ◽  
Modal Reduction ◽  
Time Varying Parameter ◽  
The Stability

In this paper the stability of the lateral dynamic behavior of a pinned-pinned, clamped-pinned and clamped-clamped beam under axial periodic force or torque is studied. The time-varying parameter equations are derived using the Rayleigh-Ritz method. The stability analysis of the solution is based on Floquet’s theory and investigated in detail. The Rayleigh-Ritz results are compared to those of a finite element modal reduction. It is shown that the lateral instabilities of the beam depend on the forcing frequency, the type of excitation and the boundary conditions. Several experimental tests enable the validation of the numerical results.

A 3D Finite Element Study of Fatigue Life Dispersion in Rolling Line Contacts

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Nick Weinzapfel ◽  
Farshid Sadeghi ◽  
Vasilios Bakolas ◽  
Alexander Liebel
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Material Properties ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Critical Shear Stress ◽  
Rolling Contact ◽  
Shear Stresses ◽  
Rolling Element Bearings ◽  
Rolling Element

Rolling contact fatigue of rolling element bearings is a statistical phenomenon that is strongly affected by the heterogeneous nature of the material microstructure. Heterogeneity in the microstructure is accompanied by randomly distributed weak points in the material that lead to scatter in the fatigue lives of an otherwise identical lot of rolling element bearings. Many life models for rolling contact fatigue are empirical and rely upon correlation with fatigue test data to characterize the dispersion of fatigue lives. Recently developed computational models of rolling contact fatigue bypass this requirement by explicitly considering the microstructure as a source of the variability. This work utilizes a similar approach but extends the analysis into a 3D framework. The bearing steel microstructure is modeled as randomly generated Voronoi tessellations wherein each cell represents a material grain and the boundaries between them constitute the weak planes in the material. Fatigue cracks initiate on the weak planes where oscillating shear stresses are the strongest. Finite element analysis is performed to determine the magnitude of the critical shear stress range and the depth where it occurs. These quantities exhibit random variation due to the microstructure topology which in turn results in scatter in the predicted fatigue lives. The model is used to assess the influence of (1) topological randomness in the microstructure, (2) heterogeneity in the distribution of material properties, and (3) the presence of inherent material flaws on relative fatigue lives. Neither topological randomness nor heterogeneous material properties alone account for the dispersion seen in actual bearing fatigue tests. However, a combination of both or the consideration of material flaws brings the model’s predictions within empirically observed bounds. Examination of the critical shear stress ranges with respect to the grain boundaries where they occur reveals the orientation of weak planes most prone to failure in a three-dimensional sense that was not possible with previous models.

scholarly journals Shock Tube Testing and Modelling of Annealed Float Glass

2018 ◽  
Vol 183 ◽  
pp. 01035
Author(s):  
Karoline Osnes ◽  
Tore Børvik ◽  
Odd Sture Hopperstad
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Prediction Model ◽  
Shock Tube ◽  
Fracture Strength ◽  
Blast Loading ◽  
Experimental Tests ◽  
Float Glass ◽  
Strength Prediction ◽  
Glass Strength

Failure of glass is dominantly brittle, and is caused by microscopic flaws randomly distributed on the surface. Fracture mainly initiates in these flaws, and this leads to a high variability in the glass strength, which depends on geometry, boundary conditions and loading situation. Consequently, the identification of the fracture strength, in e.g. finite element analyses, is not straightforward. For rapid loading conditions, as for blast loading situations, the glass strength is generally increased because flaws need time to grow into cracks. The current study aims to identify the probabilistic fracture strength of glass plates under blast loading as a function of the plate?s boundary conditions, geometry and loading by using a newly proposed strength prediction model. To validate this model in some measure, 12 blast tests on annealed float glass were performed in a shock tube. As expected, the tests showed a large scatter in fracture strength. The strength prediction model captured the main trends found in the experimental tests, but a closer investigation of the strain rate sensitivity of glass was deemed necessary. Finally, the results from the strength prediction model were used as input in a simulation of annealed float glass under blast pressure in the finite element program IMPETUS Afea Solver. By use of a node splitting technique, the simulations captured the behaviour displayed in the experimental tests to a great extent.

Thermal stressing of plain and prestressed masonry diaphragm walls

1996 ◽  
Vol 23 (4) ◽  
pp. 850-861 ◽  
Author(s):  
N. G. Shrive ◽  
A. Huizer ◽  
D. Tilleman ◽  
W. Eng
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Thermal Loading ◽  
Thermal Stresses ◽  
Thermal Analyses ◽  
Experimental Tests ◽  
Cross Wall ◽  
Thermal Tests ◽  
Simple Method ◽  
Diaphragm Walls

Diaphragm walls constitute a structurally efficient form of masonry. The effects of the large cross-wall temperature differentials which can develop during winter need to be examined. Finite element models of diaphragm walls were analysed to determine if thermal stresses could potentially cause structural distress. For validation, model walls were subjected to flexural loading and the results were compared with those from experimental tests on similar walls. Good agreement was found. Therefore, thermal analyses were performed. It was found that the resulting stresses were heavily dependent on the structural boundary conditions, but indicated the potential of cracking. Series of 2 and 3 m high walls were therefore constructed and subjected to thermal loading. The walls were subjected to different boundary conditions. The 3 m high walls were tested both plain and prestressed. None of the walls cracked as a result of the thermal loading. A simple method is presented for estimating the change in prestress force due to the temperature change in the wall. Key words: masonry, diaphragm walls, cavity walls, thermal tests, post-tensioning finite element modelling.

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