scholarly journals Optimization and Design of a Railway Wheel Profile Based on Interval Uncertainty to Reduce Circular Wear

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yongjie Lu ◽  
Yun Yang ◽  
Jianxi Wang ◽  
Bowen Zhu
Keyword(s):  
Sampling Technique ◽  
Numerical Approach ◽  
Interval Uncertainty ◽  
Wheel Wear ◽  
Stick Slip ◽  
Mechanics Model ◽  
Design Cycle ◽  
Speed Fluctuation ◽  
Slip Area ◽  
Wheel Profile

Wheel tread wear is a form of wheel damage that can seriously affect the performance of freight vehicles. A new numerical approach to optimizing wheel profiles can reduce circular wear on the LM wheel in the design cycle. This approach considers the influence of different line conditions and speed fluctuation on wheel wear, along with the performance of the wheel and the rail as the materials wear. In this approach, a nonlinear numerical optimization model for the wheel tread profile is built through a backpropagation (BP) neural network method. The multipoint Kik–Piotrowski (KP) contact mechanics model is applied to calculate the wheel/rail normal force, tangential creep force, the stick-slip area, and the size and shape of the contact patch. The optimal profile is obtained through the genetic algorithm (GA) method. In order to better reflect the random characteristics of wheel/rail matching and interval uncertainty, a random sampling technique is used to generate a random data sample at typical operating speeds.

Simulation and measurement study of metro wheel wear based on the Archard model

2019 ◽  
Vol 71 (2) ◽  
pp. 284-294 ◽  
Author(s):  
AiHua Zhu ◽  
Si Yang ◽  
Qiang Li ◽  
JianWei Yang ◽  
Xi Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Measured Data ◽  
Sequence Type ◽  
Dynamics Model ◽  
Wheel Wear ◽  
Matlab Software ◽  
Hertz Theory ◽  
Content Type ◽  
Vehicle Load ◽  
Wheel Profile

PurposeThe purpose of this paper is to study the wear evolution of metro wheels under the conditions of different track sequences, track composition and vehicle load and then to predict wheel wear and to guide its maintenance.MethodologyBy using the SIMPACK and MATLAB software, numerical simulation analysis of metro wheel wear is carried out based on Hertz theory, the FASTSIM algorithm and the Archard model. First of all, the vehicle dynamics model is established to calculate the motion relationship and external forces of wheel-rail in the SIMPACK software. Then, the normal force of wheel-rail is solved based on Hertz theory, and the tangential force of wheel-rail is calculated based on the FASTSIM algorithm through the MATLAB software. Next, in the MATLAB software, the wheel wear is calculated based on the Archard model, and a new wheel profile is obtained. Finally, the new wheel profile is re-input into the vehicle system dynamics model in the SIMPACK software to carry out cyclic calculation of wear.FindingsThe results show that the setting order of different curves has an obvious influence on wear when the proportion of the straight track and the curve is fixed. With the increase in running mileage, the severe wear zone is shifted from tread to flange root under the condition of the sequence-type track, but the wheel wear distribution is basically stable for the unit-type track, and their wear growth rates become closer. In the tracks with different straight-curved ratio, the more proportion the curved tracks occupy, the closer the severe wear zone is shifted to flange root. At the same time, an increase in weight of the vehicle load will aggravate the wheel wear, but it will not change the distribution of wheel wear. Compared with the measured data of one city B type metro in China, the numerical simulation results of wheel wear are nearly the same with the measured data.Practical implicationsThese results will be helpful for metro tracks planning and can predict the trend of wheel wear, which has significant importance for the vehicle to do the repair operation. At the same time, the security risks of the vehicle are decreased economically and effectively.Originality/valueAt present, many scholars have studied the influence of metro tracks on wheel wear, but mainly focused on a straight line or a certain radius curve and neglected the influence of track sequence and track composition. This study is the first to examine the influence of track sequence on metro wheel wear by comparing the sequence-type track and unit-type track. The results show that the track sequence has a great influence on the wear distribution. At the same time, the influence of track composition on wheel wear is studied by comparing different straight-curve ratio tracks; therefore, wheel wear can be predicted integrally under different track conditions.

Use of Archard’s Wear Law for the Calculation of Uniform Wheel Wear of High Tonnage Freight Vehicles

2013 ◽  
Author(s):  
Carlos Casanueva ◽  
Per-Anders Jönsson ◽  
Sebastian Stichel
Keyword(s):  
Contact Point ◽  
Wheel Wear ◽  
Contact Conditions ◽  
Passenger Vehicles ◽  
Calculation Methodology ◽  
Wear Calculation ◽  
Wheel Profile ◽  
Wear Law ◽  
Equivalent Conicity ◽  
Freight Vehicles

Wheel profile evolution has a large influence on track and wheelset related maintenance costs. It influences important parameters such as equivalent conicity or contact point positioning, which will affect the dynamic behavior of the vehicle, in both tangent track and curve negotiation. High axle loads in freight wagons may increase both the wheel wear and the damage caused by vehicles with both new and already worn profiles. A common profile in Europe is the S1002 profile, developed for rail inclination 1/40. In Sweden rail inclination is 1/30, so contact conditions might not be optimal. The presented work uses Archard’s wear law to analyze the profile wear evolution in a two axle freight vehicle with Unitruck running gear on the Swedish network. This wear calculation methodology has been successfully used to predict uniform wear in passenger vehicles. First, the vehicle model has been optimized in order to improve the speed of the wear simulations. Experimental measurements of wheel profiles have been performed in order to validate the simulations. The conclusion is that the wear methodology successfully used to predict uniform wheel wear in passenger vehicles cannot be directly applied for the calculation of wheel profile evolution in high tonnage freight vehicles. The influence of block brakes or switches and crossings cannot be dismissed when calculating uniform wheel wear in these cases.

Wheel-Wear Compensation for Numerical Form Grinding

1986 ◽  
Vol 108 (1) ◽  
pp. 16-21 ◽  
Author(s):  
T. Giridharan ◽  
R. C. Dix ◽  
S. Nair
Keyword(s):  
Method Of Characteristics ◽  
Grinding Wheel ◽  
Surfaces Of Revolution ◽  
Wheel Wear ◽  
Closed Form Solutions ◽  
First Order ◽  
Grinding Wheel Wear ◽  
Form Grinding ◽  
Wheel Profile ◽  
Wheel Wear Compensation

A new method for reducing the effect of grinding wheel wear on workpiece inaccuracy in numerically controlled form grinding of surfaces of revolution is proposed and analyzed. A mathematical model to describe wheel wear and contour production is developed for the grinding of a cyclindrical surface. The model results in a first-order hyperbolic differential equation for the radius of the wheel profile as a function of time and position. This equation is solved numerically using the method of characteristics. Closed-form solutions are also presented for a simplifed version of this equation. Pertinent results, such as reduction in the error in the workpiece radius, are presented to demonstrate the effectiveness of the proposed method.

Influence of Wheel-Rail Profiles on the Hunting Vibrations of Rail Vehicle Trucks

1985 ◽  
Vol 107 (2) ◽  
pp. 167-174 ◽  
Author(s):  
A. F. D’Souza ◽  
W-J. Tsung
Keyword(s):  
Dynamic Performance ◽  
Equations Of Motion ◽  
Algebraic Equations ◽  
Wheel Wear ◽  
Hunting Behavior ◽  
Describing Functions ◽  
High Acceleration ◽  
Nonlinear Algebraic Equations ◽  
Wheel Profile ◽  
Freight Trucks

The effect of several wheel and rail profiles on the hunting behavior of three-piece North American freight truck is investigated by the method of describing functions. After replacing the nonlinear terms by their equivalent describing functions, the differential equations of motion are converted to a set of coupled nonlinear algebraic equations which are then solved by the Newton-Raphson method. It is shown that the wearing of the rail profile has a significant adverse effect on the dynamic behavior. It greatly lowers the critical speed for the onset of hunting and raises the frequency, thereby causing high acceleration levels. It is also shown that the modified Heumann wheel profile exhibits a superior dynamic performance for freight trucks than the standard new wheel profile used in North America. The effects of wheel wear and loads on hunting are also investigated.

scholarly journals Deformation properties of self-adapting wind turbine blades numerical approach and optimization

2019 ◽  
Vol 23 (4) ◽  
pp. 2397-2402
Author(s):  
Xiao Chen ◽  
Li Qiu ◽  
Qiang Cen
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Turbine Blades ◽  
Numerical Approach ◽  
Wind Turbine Blades ◽  
Wind Speeds ◽  
Mechanics Model ◽  
Deformation Properties ◽  
Glass Carbon ◽  
Flexible Deformation

All wind-driven generators need to be equipped with brakes to ensure operational control and safety. Many methods are available to avoid over-speed of the blower. This paper establishes a mechanics model to investigate each point on turbine blades, which are such designed that they would change shape in high winds to reduce the frontal area through adaptive and flexible deformation. In this way, high wind speeds will cause deformation of the blades and decrease of the rotational speed, as a result the turbine slows down. A numerical analysis of the fluid in the fan housing and a force analysis of the blades are performed, and numerical results are used to design the non-uniform arrangement of the hybrid glass/carbon fiber. A wind tunnel experiment is performed on the new blade design. The experimental results show that the new blade achieves an improvement in its mechanical properties and is able to adaptively adjust the torque. During the operation of the wind-driven generator, the new blade could effectively broaden the operational range of wind speeds, thereby improving the power generation when the wind speed is low. A generator without a brake stalls when the wind speed exceeds 13 m/s. After the adoption of the self-adaptive blade made up of the uniform-section complex textile material, the power set shows reduction of noise, avoidance of blade runaway, improvement of the efficiency of the power generation, decrease of cost and enhancement of blade consistency.

scholarly journals Modelling car motion and the calculation of the wear of wheels with the VNITsTT rolling surface profile

2019 ◽  
Vol 78 (1) ◽  
pp. 41-47
Author(s):  
A. M. Orlova ◽  
Yu. V. Savushkina ◽  
V. I. Fedorova
Keyword(s):  
Mathematical Modeling ◽  
Critical Speed ◽  
Surface Profile ◽  
Operating Conditions ◽  
Wheel Wear ◽  
Large Circle ◽  
Limit Values ◽  
Rolling Surface ◽  
Wheel Profile ◽  
Freight Car

The wear problem of wheels along rolling surface or thin flange is currently involved a large circle of specialists. There are opinions that it is necessary to establish new limit values for wheel wear in operation, put into practice the re-profiling (profile grin ding) of rails, install a larger number of floor-mounted lubricators in places of increased rail wear intensity, but one of the priority direction in this area is the development of a new surface rolling wheel profile for freight cars, the use of which will help to increase the turnaround time and increase the service life of the wheels in operation. Geometry of the rolling surface profile of the wheel should allow to provide a contact form between the wheel and the rail conformal or close to conformal. This solution has already found its application and achieved desired results on foreign railways (North America, South Africa, China, etc.). Authors developed a technique for designing a new wheel profile, which was used to build a profile of the rolling surface made by the Russian Research Center for Transport Technologies (LLC “VNITsTT”). As part of the study, calculations were carried out using the method of mathematical modeling of a freight car motion in the MEDYNA software package and performance indicators were evaluated on the VNITsTT rolling surface profile in comparison with the profile made according to GOST 10791 – 2011, and the wheel wear rate produced on the section of the track close to the average network operating conditions. Additionally, critical speed of the sinuous motion of the car was evaluated, which showed that despite the increased equivalent taper, the critical speed remained almost unchanged (an increase of 6 %). Theoretical calculation of the wheel resource based on the results of mathematical modeling has been made. According to the calculations, it was determined that the resource of the flange before turning for the RDCTT profile is 409.3 thousand km, and for the rolling surface — 663.3 thousand km, for the profile made according to GOST 10791 – 2011, the resource for the flange was 285.6 thousand km, and for the rolling surface 401.2 thousand km. Thus, the use of the VNITsTT profile is more effective than the profile made according to GOST 10791 – 2011 by 30.2 % for the flange and 39.5 % for the rolling surface. The developed VNITsTT profile, in comparison with the profile made by GOST 10791 – 2011, according to the results of calculations, confirmed the provision of standard indicators of the dynamic qualities of a freight car. 

scholarly journals A new methodology to simulate subglacial deformation of water saturated granular material

2015 ◽  
Vol 9 (4) ◽  
pp. 3617-3660 ◽  
Author(s):  
A. Damsgaard ◽  
D. L. Egholm ◽  
J. A. Piotrowski ◽  
S. Tulaczyk ◽  
N. K. Larsen ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Fluid Pressure ◽  
Fluid Phase ◽  
Large Degree ◽  
Numerical Approach ◽  
Unconsolidated Sediments ◽  
Close Monitoring ◽  
Stick Slip ◽  
Rate Dependent ◽  
Water Saturated

Abstract. The dynamics of glaciers are to a large degree governed by processes operating at the ice–bed interface, and one of the primary mechanisms of glacier flow over soft unconsolidated sediments is subglacial deformation. However, it has proven difficult to constrain the mechanical response of subglacial sediment to the shear stress of an overriding glacier. In this study, we present a new methodology designed to simulate subglacial deformation using a coupled numerical model for computational experiments on grain-fluid mixtures. The granular phase is simulated on a per-grain basis by the discrete element method. The pore water is modeled as a compressible Newtonian fluid without inertia. The numerical approach allows close monitoring of the internal behavior under a range of conditions. The rheology of a water-saturated granular bed may include both plastic and rate-dependent dilatant hardening or weakening components, depending on the rate of deformation, the material state, clay mineral content, and the hydrological properties of the material. The influence of the fluid phase is negligible when relatively permeable sediment is deformed. However, by reducing the local permeability, fast deformation can cause variations in the pore-fluid pressure. The pressure variations weaken or strengthen the granular phase, and in turn influence the distribution of shear strain with depth. In permeable sediments the strain distribution is governed by the grain-size distribution and effective normal stress and is typically on the order of tens of centimeters. Significant dilatant strengthening in impermeable sediments causes deformation to focus at the hydrologically more stable ice–bed interface, and results in a very shallow cm-to-mm deformational depth. The amount of strengthening felt by the glacier depends on the hydraulic conductivity at the ice–bed interface. Grain-fluid feedbacks can cause complex material properties that vary over time, and which may be of importance for glacier stick-slip behavior.

Stochastic Analysis of Transit Wheel Wear and Optimized Forecasting of Wheel Maintenance Requirements

2019 ◽  
Author(s):  
Joseph W. Palese ◽  
Allan M. Zarembski ◽  
Kyle Ebersole
Keyword(s):  
New York ◽  
Wheel Running ◽  
Measurement Data ◽  
Wheel Wear ◽  
Flange Thickness ◽  
Maintenance Practice ◽  
Wheel Profile ◽  
Maintenance Requirements ◽  
Flange Angle ◽  
Very High

As transit vehicle wheels accrue mileage, they experience flange and tread wear based on the contact between the railhead and wheel-running surface. When wheels wear excessively, the likelihood of accidents and derailments increases. Thus, regular maintenance is performed on the wheels, until they require replacement. One common maintenance practice is truing; using a specially designed cutting machine to bring a wheel back to an acceptable profile. This process removes metal from the wheel and is often based on wheel flange thickness standards (and sometimes wheel flange angle). Wheel replacement is usually driven by rim thickness, which is continually reduced by wear and metal removed by truing. This research study used wheel wear data provided by the New York City Transit Authority (NYCTA) to analyze wheel wear trends and forecast wheel maintenance (truing based on flange thickness) and wheel life (replacement based on rim thickness). Using automatic wheel-scanning technology, NYCTA was able to collect wheel profile measurements for nearly 4,000 wheels in its fleet over a six-month period, measured weekly. The resulting wheel measurement data was analyzed using advanced stochastic techniques to determine relationships for the changes in flange thickness over time for each wheel in the fleet. Flange thickness wear rate relationships for each wheel were then used to forecast the time it would take for a wheel to reach the flange thickness maintenance threshold as defined by NYCTA standards. Furthermore, a subpopulation of wheels that exhibited very high rates of wear were classified as “bad actors” and identified for further investigation to understand the cause of accelerated wear. This allows for identification and addressing of causal factors that relate to accelerated wear, such as angle of attack and L/V ratio. NYCTA has recently started capturing such data that relates truck performance, which can be related to rate of wear.

Optimal profile design for rail grinding based on wheel–rail contact, stability, and wear development in high-speed electric multiple units

2019 ◽  
Vol 234 (6) ◽  
pp. 666-677
Author(s):  
Kai Xu ◽  
Zheng Feng ◽  
Hao Wu ◽  
Dongri Xu ◽  
Fu Li ◽  
...  
Keyword(s):  
High Speed ◽  
Simulation Software ◽  
Single Type ◽  
Large Radius ◽  
Wheel Wear ◽  
Railway Line ◽  
Rail Grinding ◽  
Wheel Profile ◽  
Profile Design ◽  
Multiple Units

High-speed electric multiple units have numerous advantages. However, a number of critical maintenance issues arise in the operation of high-speed electric multiple units. The previous researches about rail profile design usually take only a single type of wheel profile into account, which would cause some other problems such as severe increase of hollow wear on the wheels. This study systematically investigates the influence of rail grinding on running stability and wear development in high-speed electric multiple units and designs a new rail profile as reference for grinding that takes all types of vehicle wheels running on a specific line into account, in order to design a ground rail which could match the wheel profile and thus improve the running stability of electric multiple units. All types of wheel profiles used on the Wuhan–Guangzhou railway line are taken as the design reference. A wheel–rail wear simulation program is constructed based on CONTACT numerical simulation software and SIMPACK vehicle system dynamics software. The simulation results show that both the wheel–rail contact relationship and the running stability of high-speed electric multiple units improved after rail grinding. The results of the wheel wear analysis show that when the rail is ground to the target profile, after a running mileage of 200,000 km, the wear area of the new wheel profile LMA and the greatest hollow wear wheel profile LMA-25 decreases by 1.13 mm2 and 9.86 mm2, respectively. In addition, this method can prolong the wheel reprofiling interval. For the Wuhan–Guangzhou railway line, normally the grinding interval for the tangent track and large-radius curve is 2–3 years, and for the entering and exiting tunnel sections, the grinding interval should be set for 1–2 years, which could remove the damaged layer of the rail surface and could restore the designed profile of the rail and prolong the rail service life.

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