scholarly journals Fatigue Damage of an Asperity in Frictionless Normal Contact with a Rigid Flat

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 545
Author(s):  
Zhou Chen ◽  
Yibo Jiang ◽  
Zheming Tong ◽  
Shuiguang Tong
Keyword(s):  
Fatigue Damage ◽  
Element Model ◽  
Fatigue Wear ◽  
Research Directions ◽  
Normal Loading ◽  
Normal Contact ◽  
Slowing Down ◽  
Surface Fatigue ◽  
Severe Fatigue ◽  
Elastic Shakedown

Surface fatigue wear widely exists, and it occurs as long as a sufficient number of loading–unloading cycles are applied. Slowing down surface fatigue wear requires understanding the evolution of fatigue damage in the surface. Real surfaces are composed of many asperities; therefore, it is important to study the fatigue damage of a single asperity. A finite element model of an asperity subjected to cyclic elastic–plastic normal loading was developed under frictionless contact condition. The asperity can be either completely or partially unloaded in a loading cycle. For the sake of completeness, both cases were investigated in the present study. The multiaxial Fatemi-Socie fatigue criterion was adopted to evaluate the fatigue damage of the asperity in elastic shakedown state, which was achieved after several loading cycles. For the case of complete unloading, severe fatigue damage was confined in a subsurface ridge starting from the edge of the maximum loaded contact area. The shape and volume of the wear particles were predicted based on a fundamentally valid assumption. For the case of partial unloading, the fatigue damage was much milder. Finally, potential research directions to expand the current study are suggested.

Fatigue analysis of spherical contact subjected to cyclic elastic-plastic normal loading

2021 ◽  
pp. 1-20
Author(s):  
Zhou Chen ◽  
Yibo Jiang ◽  
Zheming Tong ◽  
Shuiguang Tong ◽  
Jianrong Tan
Keyword(s):  
Rough Surface ◽  
Fatigue Damage ◽  
Contact Fatigue ◽  
Future Research ◽  
Research Directions ◽  
Normal Loading ◽  
Elastic Plastic ◽  
Surface Fatigue ◽  
Future Research Directions ◽  
Maximum Contact

Abstract Surface fatigue resulting from cyclic contact loading is a main reason for the rough surface wear. Since a rough surface consists of many asperities, the fatigue in one asperity is investigated. The multiaxial Fatemi-Socie fatigue criterion is adopted to study the contact fatigue in a spherical asperity subjected to cyclic elastic-plastic normal loading. The fatigue damage in the asperity is predicted. The maximum fatigue damage occurs at the edge of the maximum contact area. Two typical patterns are found for the fatigue damage distribution. Locations and orientations of fatigue microcrack initiation are also identified. Finally, future research directions are discussed.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

Applications of vibro-acoustic measurement and analysis in conjunction with tribological parameters to assess surface fatigue wear developed in the roller-bearing system

2021 ◽  
pp. 135065012098246
Author(s):  
Shashikant Pandey ◽  
Muniyappa Amarnath
Keyword(s):  
Roller Bearing ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Stribeck Curve ◽  
Fatigue Wear ◽  
Surface Fatigue ◽  
Rolling Element ◽  
Measurement And Analysis ◽  
Contact Surfaces ◽  
Bearing System

Rolling-element bearings are the most commonly used components in all rotating machinery. The variations in the operating conditions such as an increase in the number of operating cycles, load, speed, service temperature, and lubricant degradation result in the development of various defects such as pitting, spalling, scuffing, scoring, etc. The defects that appeared on rolling contact surfaces cause surface deterioration and change in the vibration and sound levels of the bearing system. The present experimental investigations are aimed at assessing the surface fatigue wear that appears on the contact surfaces of roller bearings. The studies considered the estimation of specific film thickness, analysis of surface fatigue wear developed on the rolling-element surfaces, surface roughness analysis, grease degradation analysis using Fourier transform infrared radiation, and vibration and sound signal measurement and analysis. The results obtained from the experimental investigation provide a good correlation between surface wear, vibration, and sound signals with a transition in the lubrication regimes in the Stribeck curve.

On the Source of the Systematic Error of the Pressure Measurement Film Applied to Wheel–Rail Normal Contact Measurements

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Jagoba Lekue ◽  
Florian Dörner ◽  
Christian Schindler
Keyword(s):  
Finite Element ◽  
Measurement Error ◽  
Systematic Error ◽  
Pressure Measurement ◽  
Element Model ◽  
Normal Contact ◽  
Failure Pressure ◽  
Research Activities ◽  
Element Failure ◽  
Simulation Results

This paper presents research activities regarding the systematic error of the pressure measurement film when measuring the area of the wheel–rail contact. In particular, an explanation for the different error values shown by the different film types was sought. A finite element model was created based on the assumption that not only the film, but also the microcapsules on top of it alter the results. The performance of the existing film models was enhanced by defining microcapsules with element failure and deletion behaviors. The new model was capable of reproducing the trend shown by the systematic error in the experiments. The simulation results confirmed that the measurement error of a certain film type is not only caused by the film itself, but also depends on the failure pressure and especially the diameter of the capsules.

Structural health monitoring and fatigue damage estimation using vibration measurements and finite element model updating

2018 ◽  
Vol 18 (4) ◽  
pp. 1189-1206 ◽  
Author(s):  
Dimitrios Giagopoulos ◽  
Alexandros Arailopoulos ◽  
Vasilis Dertimanis ◽  
Costas Papadimitriou ◽  
Eleni Chatzi ◽  
...  
Keyword(s):  
Finite Element ◽  
Structural Health Monitoring ◽  
Finite Element Model ◽  
Fatigue Damage ◽  
Health Monitoring ◽  
Model Updating ◽  
Element Model ◽  
Finite Element Model Updating ◽  
Damage Estimation ◽  
Vibration Measurements

Fatigue Reliability Assessment for Brace-Column Details in a Semi-Submersible Hull

2014 ◽  
Author(s):  
Dilnei Schmidt ◽  
Lance Manuel ◽  
Hieu H. Nguyen ◽  
Luis Volnei Sudati Sagrilo ◽  
Edison Castro Prates de Lima
Keyword(s):  
Reliability Analysis ◽  
Fatigue Damage ◽  
Hot Spot ◽  
Response Spectra ◽  
Element Model ◽  
Response Analysis ◽  
Fatigue Reliability ◽  
Hot Spot Stress ◽  
Axial Forces ◽  
Uncertainty Estimates

Semi-submersible floating platforms used in the offshore deepwater environment have hull structures that are comprised of vertical cylinders (columns) connected by braces, pontoons, etc. Several of the connections between these various members are susceptible to fatigue damage. In fatigue damage assessment or fatigue reliability analysis, a global structural response analysis is typically carried out using a finite element model where internal forces or stresses in the various members are evaluated for specified sea states of interest at the site. Of specific interest in this study is the fatigue reliability analysis of brace-column connection details in a semi-submersible hull unit for selected Brazilian environmental conditions. Stress concentration factors for the selected critical hot spots are applied to the nominal component stresses due to axial forces and biaxial bending. The hot-spot stress response spectra are used with various spectral methods — referred to as Rayleigh, Modified Rayleigh (with bandwidth correction), and Dirlik — to estimate fatigue damage using Miner’s rule. Uncertainty estimates in fatigue damage rates and life based on the various methodologies are discussed and critical sea states are identified, highlighting dynamic and quasi-static influences on the predicted fatigue.

Effect of Crystallographic Texture on Deformation Fields in Fretting Contacts

2005 ◽  
Author(s):  
J. R. Mayeur ◽  
D. L. McDowell ◽  
R. W. Neu
Keyword(s):  
Plastic Strain ◽  
Half Space ◽  
Crystallographic Texture ◽  
Element Model ◽  
Partial Slip ◽  
Slip Regime ◽  
Microstructural Heterogeneity ◽  
Alpha Beta ◽  
Cyclic Plastic Strain ◽  
Elastic Shakedown

Fretting contacts in the partial slip regime are simulated by a finite element model of a rigid cylinder on an elastic-crystal viscoplastic half-space. The half-space is modeled as duplex Ti-6Al-4V, a polycrystalline metal alloy consisting of equiaxed primary alpha grains and secondary lamellar alpha+beta grains. Various realistic 3-D crystallographic textures are considered. The deformation fields generated by fretting are quantified in terms of cumulative effective plastic strain distributions and plastic strain maps. The results clearly demonstrate the importance of the various sources of microstructural heterogeneity in the surface layers. The main sources of microstructural heterogeneity include the distribution of phases, slip system strength anisotropy, and crystallographic texture. In basal textured materials with fretting on the edge, the plastic strain is more evenly distributed in the subsurface regions than in other textured cases. This is explained by the greater number of grains able to deform by soft slip modes and the symmetry of this type of texture relative to the fretting orientation. Transverse and basal/transverse textures result in more heterogeneously-distributed plastic strain with strain often concentrated in narrow vein-like structures with maximum accumulation near alpha/alpha+beta grain boundaries. Elastic shakedown is more difficult to achieve in the later case. Ratcheting is the primary mechanism for cyclic plastic strain accumulation.

Fatigue damage of a heavy-haul railway tunnel invert under a 33-tonne axle cyclic load

2019 ◽  
Vol 234 (5) ◽  
pp. 498-510
Author(s):  
Mingnian Wang ◽  
Yinting Zhao ◽  
Ziqiang Li ◽  
Dagang Liu ◽  
Li Yu
Keyword(s):  
Fatigue Damage ◽  
Cyclic Load ◽  
Large Scale ◽  
Surrounding Rock ◽  
Monitoring Methods ◽  
In Situ Tests ◽  
Railway Tunnel ◽  
Severe Fatigue ◽  
Heavy Haul ◽  
Heavy Haul Railway

The average cyclic load of heavy-haul railway trains is generally larger than that of a conventional mixed passenger and freight railway. This load leads to more severe fatigue damage to structures, including the concrete in a tunnel invert. This study focuses on the fatigue damage of a tunnel invert under a cyclic load of 33 tonnes. The damage classifications for the tunnel inverts are given based on field investigations. With large-scale in-situ tests on the Zhang-Tang Heavy-Haul Railway Tunnel, the pressure–time distributions for the additional dynamic stresses on the surface of the track-bed for various classes of the surrounding rock are proposed. They were subsequently validated against numerical simulation using the ANSYS Workbench module. Fatigue damage of the tunnel invert is demonstrated using both numerical and monitoring methods. It has been observed that the damage to the tunnel invert becomes severe and extensive if the quality of the surrounding rock degrades. Damage zones develop first at the top of the invert and then expand to a deeper position, depending on the rock grade.

Repairing Surface Fatigue Damage of the Metal Material by Heat Treatment

2010 ◽  
Vol 154-155 ◽  
pp. 425-428
Author(s):  
Ting Liang Guo ◽  
Zhao Xing Han
Keyword(s):  
Heat Treatment ◽  
Fatigue Damage ◽  
Material Surface ◽  
Temperature Threshold ◽  
Threshold Behavior ◽  
Tempering Temperature ◽  
Metal Material ◽  
Surface Fatigue ◽  
Material Fatigue ◽  
Metal Materials

In this paper, using experimental method studied to repair surface fatigue damage of the metal material by heat treatment. Analyzed the mechanism to repair surface fatigue damage of the metal material by heat treatment. From the test, it have been found that the Metal materials has temping threshold behavior in repairing it’s fatigue damage by heat treatment. For the same kind of material, there is a threshold characteristics in choosing tempering temperatures when repaired the fatigue damage of metal material surface through changed tempering temperatures. Experimental results shows that the temping temperature threshold to repair metal material fatigue damage is the first tempering temperature after materials was hardened before it was in fatigue damage.

Sensitivity analysis of the wheel–rail normal contact on the basis of continuous factors

2016 ◽  
Vol 231 (9) ◽  
pp. 1022-1034
Author(s):  
Florian Dörner ◽  
Tobias Bettinger ◽  
Christian Schindler
Keyword(s):  
Sensitivity Analysis ◽  
Rail Steel ◽  
Lateral Displacement ◽  
Element Model ◽  
Normal Contact ◽  
Wagon Wheel ◽  
Input Parameters ◽  
Important Input ◽  
Wheel Radius

The exact characterization of the wheel–rail normal contact situations is essential for its wear, fatigue, and guidance analysis. To simulate this contact, numerous input parameters are required. Many of them have to be estimated. The aim of this sensitivity analysis was to investigate the direct effects and interactions of the input parameters on the contact pressure distribution of a freight wagon wheel on a straight track. For this purpose, a finite element model was parametrized in such a way that all the parameters were continuous. This research demonstrates that the output parameters of the wheel–rail contact simulations have a broad deviation and the input variable with the most influence on the contact form and position is the lateral displacement of the wheelset. Nevertheless, the profile shape of the wheel and rail, the wheel radius, and the relative wheel–rail inclination are important input parameters as well, and also need to be considered for exact simulations of the wheel–rail contact. On the other hand, the deviation of material parameters of wheel and rail steel can be neglected.

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