Identification of Damages and Stress Analysis of Rail/Wheel Rolling Contact Region

2011 ◽  
Vol 462-463 ◽  
pp. 1152-1157 ◽  
Author(s):  
N.A. Akeel ◽  
M.A. Aziman ◽  
Zainuddin Sajuri ◽  
Ahmad Kamal Ariffin ◽  
A.W. Ikhsan
Keyword(s):  
Stress Distribution ◽  
Stress Analysis ◽  
Cross Section ◽  
Contact Area ◽  
Contact Region ◽  
Fem Simulation ◽  
High Hardness ◽  
Rolling Contact ◽  
Wheel Surface ◽  
Wheel Rolling

This paper presents the identification of damages and stress analysis of rail/wheel rolling contact region. The railhead surface of used rail track was investigated to identify damages and the hardness of the rail/wheel contact area was measured. Finite element method FEM code, ANSYS was used to determine the stress distribution at vicinity of rail/wheel contact area. The results showed that the hardness increased on the contact area between rail and wheel due to repeated rolling contact of rail and wheel surface. Severe damages and cracks were observed on the railhead surface and in the cross section of the rail at the contact region. The FEM simulation showed that the highest stress distribution regions were matched with the area of severely damage and high hardness obtained from the observation and experimental results.

scholarly journals Stress Analysis of HCPB BB under Ex-Vessel LOCA Condition

2021 ◽  
Vol 2108 (1) ◽  
pp. 012088
Author(s):  
Mengdi Dai ◽  
Xiaomo Wang
Keyword(s):  
Stress Distribution ◽  
Stress Field ◽  
Stress Analysis ◽  
Cross Section ◽  
Maximum Stress ◽  
Fusion Reactor ◽  
Vacuum Vessel ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Size Dimension

Abstract Helium Cooled Pebble Bed Breeding Blanket (HCPB BB) is a kind of concept for the European demonstration fusion reactor (DEMO). The blanket attachment system plays an important role in the mechanical connection of the BB and vacuum vessel. Typically, the mechanical and thermal loads should meet the requirement to avoid collapse of the system with off-normal conditions, e.g., under ex-vessel Loss of Coolant Accident (LOCA. This paper investigates the loading requirement corresponding to the maximum stress that can sustain to avoid the LOCA condition. Firstly, a model of the BB is constructed using SolidWorks. Then, stress analysis is carried out based on the cross section of the blanket. Through simulation, the critical condition for the LOCA case and the maximum stress value for the model are obtained. According to the relevant size dimension from the reference, the blanket’s cross section is drawn, and one can get the stress field under the ex-vessel LOCA through stress analysis. The stress distribution under the ex-vessel LOCA condition is simulated to find out the maximum stress field that the blanket can sustain through this paper. The significance is to predict the possible conditions leading to an accident and find possible methods to avoid them.

Investigation of rolling wheel–rail contact using an elaborate numerical simulation

2019 ◽  
Vol 234 (10) ◽  
pp. 1198-1209
Author(s):  
Fuchun Xue
Keyword(s):  
Stress Distribution ◽  
Contact Area ◽  
Rolling Contact ◽  
Local Concentration ◽  
Distribution Mode ◽  
Infrastructure System ◽  
Vertical Contact ◽  
Rolling Wheel ◽  
Contact Stress Distribution ◽  
Random Irregularity

In this paper, a non-linear model is developed for analyzing rolling wheel–rail contact in a wheel–track–infrastructure system. Because of the random irregularity across the surface of the rail, the process of the wheel accelerating from rest and rolling forward at its expected speed can be simulated and verified. The dynamic characteristics of the rolling wheel–rail contact at the expected speed are also carefully investigated. The results showed that the top of the rail consists of spatially curved planes due to the deformation induced by the rolling wheel. In addition to the adhesion and slipping zones, there was also a disengaging zone existing within the contact area. The random irregularity throughout the top of the rail significantly reduced the area of contact between the wheel and the rail. By comparing the Hertz contact theory with a smooth rail top, significant differences were observed in the vertical contact stress distribution mode throughout the contact area for the real wheel–rail rolling contact, with a sharp increase in the absolute values of contact pressure. The stress distribution in the contact area was highly non-uniform, and a severe local concentration of dynamic stress was observed.

scholarly journals On the Issue of Determining Relative Rail Rolling Contact Fatigue Damageability

2021 ◽  
Vol 19 (1) ◽  
pp. 6-17
Author(s):  
V. S. Kossov ◽  
A. V. Savin ◽  
O. G. Krasnov
Keyword(s):  
Fatigue Life ◽  
Contact Area ◽  
Rail Steel ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Simultaneous Action ◽  
Stress Strain ◽  
Rolling Surface ◽  
Wheel Rolling ◽  
Contact Fatigue Life

Adoption of heavy haul traffic on many railroads, comprising Russian railways, has highlighted the relevance of assessing the effect of increased axial loads on the contact fatigue life of rails.The article describes a set of theoretical studies carried out to create a scientifically substantiated method for predicting the contact fatigue life of rails depending on the values of axial loads. The stress-strain state of the contact area has been determined using the finite element model of wheel rolling on a rail. It has been found that the wheel-rail rolling contact area undergoes complex multiaxial loading with the simultaneous action of normal and shear strains. Based on the analysis of models describing multiaxial fatigue damage, the Brown–Miller model was chosen, which considers the simultaneous action of normal strains at the contact area and of maximum shear strains, which most fully describes the stress-strain state of the wheel-rail rolling contact area. To apply the Brown–Miller model, fatigue stress-strain curves for rail steel have been identified. Based on the analysis of methods for determining the parameters of stress-strain curves carried out by V. A. Troschenko, a modified Roessle– Fatemi hardness method has been applied. Based on the experimentally determined values of hardness on the rolling surface, the parameters of the curves of elastic and plastic fatigue have been revealed by calculation and experiment. To establish the damaging effect of the load from wheel rolling on a rail, the concept of relative damage per rolling cycle had been assumed which is the value inverse to the number of cycles preceding formation of a contact-fatigue crack at a given value of the axial load.Calculations of the relative damage rate of the rolling surface of rails caused by contact fatigue defects were carried out with the Fatigue software package considering mean values of the indicators of the degree of fatigue strength and plasticity of rail steel and the calculated stresses in the wheel-rail contact area, as well as the plasticity correction using Neuber method. The polynomial dependence of relative damageability of the rolling surface of rails is obtained. The established functional dependence of relative damageability of the rolling surface of rails on the values of vertical forces can be used as the basis for the developed methodology for predicting the contact fatigue life of rails.

Residual Stress and Microstructure in the Rail/Wheel Contact Zone of a Worn Railway Wheel

2006 ◽  
Vol 524-525 ◽  
pp. 911-916 ◽  
Author(s):  
Eric Wild ◽  
Walter Reimers
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
High Hardness ◽  
Residual Stress Distribution ◽  
X Ray Diffraction ◽  
Wheel Surface ◽  
X Ray ◽  
Microstructural Alterations ◽  
Hardness Values ◽  
Compressive Residual Stresses

The rail/ wheel contact comprises interactions of thermal and mechanical loadings which lead to microstructural changes in the wheel. These were investigated on a wheel from a regional train using metallographic examinations, X-ray diffraction for phase and residual stress analyses. The results show that the microstructural alterations, the carbon content and the residual stress distribution depend on the loading profile of the wheel. The formation of two different martensites (tetragonal and cubic martensite) on a wheel surface could be detected at different positions. The martensites are characterized by high hardness values, increased carbon contents in the lattice and an increased level of compressive residual stresses. Detailed structural analyses of the martensites which were formed under locally different loading and time conditions gave evidence for different structural evolutions.

Prediction of Tire Tread Wear with FEM Steady State Rolling Contact Simulation

2003 ◽  
Vol 31 (3) ◽  
pp. 189-202 ◽  
Author(s):  
D. Zheng
Keyword(s):  
Weight Loss ◽  
Steady State ◽  
Cross Section ◽  
Rolling Contact ◽  
Dynamic Simulations ◽  
Element Analysis ◽  
Vehicle Acceleration ◽  
Steady State Rolling ◽  
Driving Conditions ◽  
Rate Profile

Abstract A procedure based on steady state rolling contact Finite Element Analysis (FEM) has been developed to predict tire cross section tread wear profile under specified vehicle driving conditions. This procedure not only considers the tire construction effects, it also includes the effects of materials, vehicle setup, test course, and driver's driving style. In this algorithm, the vehicle driving conditions are represented by the vehicle acceleration histogram. Vehicle dynamic simulations are done to transform the acceleration histogram into tire loading condition distributions for each tire position. Tire weight loss rates for different vehicle accelerations are generated based on a steady state rolling contact simulation algorithm. Combining the weight loss rate and the vehicle acceleration histogram, nine typical tire loading conditions are chosen with different weight factors to represent tire usage conditions. It is discovered that the tire tread wear rate profile is changing continuously as the tire is worn. Simulation of a new tire alone cannot be used to predict the tire cross-section tread wear profile. For this reason, an incremental tread wear simulation procedure is performed to predict the tire cross section tread wear profile. Compared with actual tire cross-section tread wear profiles, good results are obtained from the simulations.

A simplified formulation of adhesion problems with elastic plates

2009 ◽  
Vol 465 (2107) ◽  
pp. 2217-2230 ◽  
Author(s):  
Carmel Majidi ◽  
George G. Adams
Keyword(s):  
Potential Energy ◽  
Contact Area ◽  
Contact Region ◽  
Bending Moment ◽  
Total Potential Energy ◽  
Work Of Adhesion ◽  
Contact Radius ◽  
Algebraic Complexity ◽  
Elastic Plates ◽  
Total Potential

The solution of adhesion problems with elastic plates generally involves solving a boundary-value problem with an assumed contact area. The contact region is then found by minimizing the total potential energy with respect to the contact area (i.e. the contact radius for the axisymmetric case). Such a procedure can be extremely long and tedious. Here, we show that the inclusion of adhesion is equivalent to specifying a discontinuous internal bending moment at the contact region boundary. The magnitude of this moment discontinuity is related to the work of adhesion and flexural rigidity of the plate. Such a formulation can greatly reduce the algebraic complexity of solving these problems. It is noted that the related plate contact problems without adhesion can also be solved by minimizing the total potential energy. However, it has long been recognized that it is mathematically more efficient to find the contact area by specifying a continuous internal bending moment at the boundary of the contact region. Thus, our moment discontinuity method can be considered to be a generalization of that procedure which is applicable for problems with adhesion.

scholarly journals STRESS DISTRIBUTION IN CROSS-SECTION OF RC COLUMN

2009 ◽  
Vol 74 (637) ◽  
pp. 425-431
Author(s):  
Ippei MARUYAMA ◽  
Masahiro SUZUKI ◽  
Masaomi TESHIGAWARA ◽  
Ryoichi SATO
Keyword(s):  
Stress Distribution ◽  
Cross Section ◽  
Rc Column

Stress Distribution in a Uniformly Rotating Equilateral Triangular Shaft

1955 ◽  
Vol 22 (2) ◽  
pp. 255-259
Author(s):  
H. T. Johnson
Keyword(s):  
Approximate Solution ◽  
Stress Distribution ◽  
Boundary Conditions ◽  
Plane Strain ◽  
Cross Section ◽  
Plane Stress ◽  
Biharmonic Equation ◽  
Approximate Solutions ◽  
Distribution Of Stresses ◽  
General Method

Abstract An approximate solution for the distribution of stresses in a rotating prismatic shaft, of triangular cross section, is presented in this paper. A general method is employed which may be applied in obtaining approximate solutions for the stress distribution for rotating prismatic shapes, for the cases of either generalized plane stress or plane strain. Polynomials are used which exactly satisfy the biharmonic equation and the symmetry conditions, and which approximately satisfy the boundary conditions.

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