Wheel/Rail Two-Point Contact Geometry With Back-of-Flange Contact

2007 ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshihiro Suda
Keyword(s):  
Dimensional Analysis ◽  
Three Dimensional ◽  
Point Contact ◽  
Numerical Procedure ◽  
Contact Geometry ◽  
Light Rail ◽  
Contact Algorithm ◽  
Rail Vehicle ◽  
Contact Points ◽  
Contact Formulation

In this investigation, a numerical procedure that can be used for the three-dimensional analysis of wheel and rail contact geometry is developed using the constraint contact formulation. The locations of contact points are determined for given lateral and yaw displacements of a wheelset when one-point contact is considered for each wheel, while these two displacements are no longer independent when the two-point contact occurs. A systematic procedure for predicting the flange as well as the back-of-flange contact points is developed and used for the two-point contact analysis of wheel and rail. Numerical results that involve tread, flange, and back-of-flange contacts are presented in order to demonstrate the use of the contact algorithm developed in this investigation. In particular, the back-of-flange contact is discussed for assessing contact configurations of wheel and grooved rail in Light Rail Vehicle (LRV) applications.

Wheel∕Rail Two-Point Contact Geometry With Back-of-Flange Contact

2008 ◽  
Vol 4 (1) ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshihiro Suda
Keyword(s):  
Point Contact ◽  
Numerical Procedure ◽  
Contact Geometry ◽  
Light Rail ◽  
Contact Algorithm ◽  
Systematic Procedure ◽  
Rail Vehicle ◽  
Contact Points ◽  
Contact Formulation ◽  
Geometry Analysis

In this investigation, a numerical procedure that can be used for the analysis of a wheel and rail contact geometry is developed using the constraint contact formulation. The locations of contact points are determined for given lateral and yaw displacements of a wheelset when one-point contact is considered for each wheel, while these two displacements are no longer independent when the two-point contact occurs. A systematic procedure for predicting the flange, as well as the back-of-flange contact points, is developed and used for the two-point contact geometry analysis of a wheel and rail. Numerical results that involve tread, flange, and back-of-flange contacts are presented in order to demonstrate the use of the contact algorithm developed in this investigation. In particular, the back-of-flange contact is discussed for assessing contact configurations of a wheel and a grooved rail in light rail vehicle applications.

Analysis of Wheel/Rail Contact Geometry in Turnout Section

2009 ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshimitsu Tanii ◽  
Yoshihiro Suda
Keyword(s):  
Point Contact ◽  
Numerical Procedure ◽  
Contact Geometry ◽  
Cross Sectional ◽  
Numerical Examples ◽  
Contact Points ◽  
Contact Configuration

In this investigation, a numerical procedure that can be used for the analysis of wheel/rail two-point contact geometries in turnout sections is developed. In turnout section, the tongue rail changes its shape along the track. Cross-sectional shapes of the tongue rail, therefore, need to be generated by interpolations along the rail and these profiles are used to determine the location of contact points for given location of wheelset along the track trajectory. Numerical examples of wheel/rail contact in point section are presented in order to demonstrate the use of the procedure developed in this investigation and the effect of wheel profiles on the contact configuration in turnout section is discussed.

Analysis of Wheel/Rail Contact Geometry on Railroad Turnout Using Longitudinal Interpolation of Rail Profiles

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshimitsu Tanii ◽  
Ryosuke Matsumura
Keyword(s):  
Point Contact ◽  
Numerical Procedure ◽  
Contact Geometry ◽  
Cross Sectional ◽  
Numerical Examples ◽  
Contact Points ◽  
The Given

In this investigation, a numerical procedure that can be used for the analysis of wheel/rail two-point contact geometries in turnout sections is developed. In turnout section, the tongue rail changes its shape along the track. Cross-sectional shapes of the tongue rail, therefore, need to be generated by interpolations along the track and these profiles are used to determine the location of contact points for the given location of wheelset. Several numerical examples are presented in order to demonstrate the use of the procedure developed in this investigation and the effect of wheel profiles on contact geometry in turnout section is discussed.

Consistent Tangent Stiffness of a Three-Dimensional Wheel–Rail Interaction Element

2021 ◽  
Author(s):  
Quan Gu ◽  
Jinghao Pan ◽  
Yongdou Liu
Keyword(s):  
Finite Element ◽  
Quadratic Convergence ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Light Rail ◽  
Software Framework ◽  
Tangent Stiffness ◽  
Rail Vehicle ◽  
Interaction Element ◽  
Nonlinear Equations Of Motion

Consistent tangent stiffness plays a crucial role in delivering a quadratic rate of convergence when using Newton’s method in solving nonlinear equations of motion. In this paper, consistent tangent stiffness is derived for a three-dimensional (3D) wheel–rail interaction element (WRI element for short) originally developed by the authors and co-workers. The algorithm has been implemented in finite element (FE) software framework (OpenSees in this paper) and proven to be effective. Application examples of wheelset and light rail vehicle are provided to validate the consistent tangent stiffness. The quadratic convergence rate is verified. The speeds of calculation are compared between the use of consistent tangent stiffness and the tangent by perturbation method. The results demonstrate the improved computational efficiency of WRI element when consistent tangent stiffness is used.

Numerical Procedure for Dynamic Simulation of Two-Point Wheel/Rail Contact and Flange Climb Derailment of Railroad Vehicles

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Shunpei Yamashita ◽  
Hiroyuki Sugiyama
Keyword(s):  
Point Contact ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Detection Algorithm ◽  
Elastic Contact ◽  
Switching Algorithm ◽  
Railroad Vehicles ◽  
Contact Formulation ◽  
Contact Constraint ◽  
Contact Detection Algorithm

In this investigation, a numerical procedure for wheel/rail contact problems in the analysis of curve negotiation of railroad vehicles is developed using constraint/elastic contact approach. In particular, this work focuses on the flange contact detection algorithm using the two-point look-up contact table and the switching algorithm from the elastic to constraint contact for the flange climb simulation. The two-point look-up contact table is used for the contact search of the second point of contact modeled using the elastic contact, while the constraint contact is used for the first point of contact on the wheel tread. Furthermore, in the flange climb simulation using the constraint contact formulation, loss of a tread contact modeled using the constraint contact occurs. Therefore, the elastic contact used for modeling the flange contact in the two-point contact state needs to be switched to the constraint contact as soon as loss of the tread contact occurs. For this reason, if the Lagrange multiplier associated with the contact constraint becomes greater than or equal to zero, the elastic contact used for the flange is switched to the constraint contact. The computational algorithm for the proposed switching algorithm is also presented. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation for modeling the two-point tread/flange contact as well as the flange climb behavior. Numerical results are in good agreement with those of the existing fully elastic contact formulation. Furthermore, it is shown that significant reduction in CPU time is achieved using the numerical procedure developed in this investigation.

Use of Finite Element and Finite Segment Methods in Modeling Rail Flexibility: A Comparative Study

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Martin B. Hamper ◽  
Antonio M. Recuero ◽  
José L. Escalona ◽  
Ahmed A. Shabana
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Mesh ◽  
Finite Segment ◽  
Safety Requirements ◽  
Contact Points ◽  
Rigid Finite Element Method ◽  
Contact Formulation ◽  
Finite Segment Method ◽  
Railroad Vehicle

Safety requirements and optimal performance of railroad vehicle systems require the use of multibody system (MBS) dynamics formulations that allow for modeling flexible bodies. This investigation will present three methods suited for the study of flexible track models while conclusions about their implementations and features are made. The first method is based on the floating frame of reference (FFR) formulation which allows for the use of a detailed finite element mesh with the component mode synthesis technique in order to obtain a reduced order model. In the second method, the flexible body is modeled as a finite number of rigid elements that are connected by springs and dampers. This method, called finite segment method (FSM) or rigid finite element method, requires the use of rigid MBS formulations only. In the third method, the FFR formulation is used to obtain a model that is equivalent to the FSM model by assuming that the rail segments are very stiff, thereby allowing the exclusion of the high frequency modes associated with the rail deformations. This FFR/FS model demonstrates that some rail movement scenarios such as gauge widening can be captured using the finite element FFR formulation. The three procedures FFR, FSM, and FFR/FS will be compared in order to establish differences among them and analyze the specific application of the FSM to modeling track flexibility. Convergence of the methods is analyzed. The three methods proposed in this investigation for modeling the movement of three-dimensional tracks are used with a three-dimensional elastic wheel/rail contact formulation that predicts contact points online and allows for updating the creepages to account for the rail deformations. Several conclusions will be drawn in view of the results obtained in this investigation.

scholarly journals Construction of Three-Dimensional Road Surface and Application on Interaction between Vehicle and Road

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Lu Yongjie ◽  
Huai Wenqing ◽  
Zhang Junning
Keyword(s):  
Quantitative Description ◽  
Three Dimensional ◽  
Point Contact ◽  
Estimation Method ◽  
Road Surface ◽  
Surface Model ◽  
Dynamical Process ◽  
Contact Points ◽  
Box Counting Dimension ◽  
The Impact

The quantitative description is given to three-dimensional micro and macro self-similar characteristics of road surface from the perspective of fractal geometry using FBM stochastic midpoint displacement and diamond-square algorithm in conjunction with fractal characteristics and statistical characteristics of standard pavement determined by estimation method of box-counting dimension. The comparative analysis between reconstructed three-dimensional road surface spectrum and theoretical road surface spectrum and correlation coefficient demonstrate the high reconstruction accuracy of fractal reconstructed road spectrum. Furthermore, the bump zone is taken as an example to reconstruct a more arbitrary 3D road model through isomorphism of special road surface with stochastic road surface model. Measurement is taken to assume the tire footprint on road surface to be a rectangle, where the pressure distribution is expressed with mean stiffness, while the contact points in the contact area are replaced with a number of springs. Two-DOF vehicle is used as an example to analyze the difference between three-dimensional multipoint-and-plane contact and traditional point contact model. Three-dimensional road surface spectrum provides a more accurate description of the impact effect of tire on road surface, thereby laying a theoretical basis for studies on the dynamical process of interaction of vehicle-road surface and the road friendliness.

Accurate Rail Vehicle Dynamic Simulations by DynaRail

2004 ◽  
Author(s):  
Jalil R. Sany
Keyword(s):  
Dynamic Simulation ◽  
Three Dimensional ◽  
Contact Geometry ◽  
Contact Angles ◽  
General Purpose ◽  
Hertzian Contact ◽  
Vehicle Dynamic ◽  
Rail Vehicle ◽  
Vehicle Systems ◽  
Vehicle Dynamic Simulation

A general purpose rail vehicle dynamic simulation tool has been developed at CAM (Center for Automated Mechanics). This tool allows the user to start any rail vehicle dynamic simulation with measured wheel and rail profile data without a need for generating pre-cooked wheel/rail contact geometry tables. Using the constrained multibody methods, the tool robustly solves the three dimensional wheel/rail interaction problem and computes the longitudinal, lateral and vertical locations of 1st and 2nd contacts, the sizes of all Hertzian contact areas, rolling radii, contact angles, normal reactions, the creepages and their associated forces and moments online and makes all the details available as outputs to the user for subsequent analysis and validation of the solution. The purpose of this study is to demonstrate the ability of the tool for predicting the detailed responses of the rail vehicle systems. For all simulations, in addition to the detailed contact reactions, the precise positions of all contacts in three-dimensional space are readily solved for and available for further considerations. This is an application paper and intends to introduce the railroad engineers and consultants to a tool that is capable of fulfilling their simulation and modeling needs for complex rail/vehicle systems. Such needs are not commonly provided by the specialized codes and very hard for the railroad engineers to fulfill them using other general purpose codes. DynaRail is particularly useful to the wheel/rail profile designers who may be concerned with the continuous movement of the contact point at an unprecedented accuracy. The online prediction and imposition of the contacts makes it possible to systematically include and consider the effect of the contact movements on its associated contact geometry variables such as the size of contact ellipses, rolling radii, contact angles and, ultimately the effect of all these on the stability and/or the resulting motion of wheel on rail.

Modeling Rail Flexibility Using Finite Element and Finite Segment Methods

2011 ◽  
Author(s):  
Martin B. Hamper ◽  
Antonio M. Recuero ◽  
Jose´ L. Escalona ◽  
Ahmed A. Shabana
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Low Frequency ◽  
Mode Shapes ◽  
Finite Segment ◽  
Safety Requirements ◽  
Contact Points ◽  
Contact Formulation ◽  
Modes Of Vibration ◽  
Floating Frame

Safety requirements and optimal performance of railroad systems require the utilization of multibody System (MBS) formulations that allow for modeling flexible bodies. This investigation will present three methods suited for the study of flexible track models while conclusions about their implementations and features are made. A validated method combining Floating Frame of Reference (FFR) and Finite Element (FE) to model flexible rails is utilized for comparison. In this procedure, component mode synthesis is used to extract a number of low-frequency modes of vibration which describe the deformation of the rail. Likewise, a method that discretizes the flexible body as a finite number of rigid elements that are linked by springs and dampers is applied for railroad simulations. This method, called Finite Segment or Rigid Finite Element (FS), can in turn be combined with FFR through the extraction of mode shapes of the FS model. Convergence of the methods is analyzed. A comparison will be made between these three procedures establishing differences among them and analyzing the specific application of FS to modeling track flexibility. The three aforementioned procedures may be applied to three-dimensional track models and will be used together with three-dimensional wheel/rail contact formulation that predicts contact points online and allows for updating the creepages to account for the rail movements and deformations. Several comparisons and conclusions will be drawn in view of the results obtained in this investigation.

Three-Dimensional Quantification of Multi-Point Contact Loads During Lumbar Spinal Manipulation

2004 ◽  
Author(s):  
Maruti R. Gudavalli ◽  
Robert M. Rowell
Keyword(s):  
Spinal Manipulation ◽  
Force Plate ◽  
Three Dimensional ◽  
Point Contact ◽  
Time Data ◽  
Rib Cage ◽  
Contact Points ◽  
Contact Loads ◽  
Pelvic Support ◽  
Hand Contact

The objective of this study was to measure the complete three-dimensional loads at each of the support contacts namely both hand contacts, and the support loads at the rib cage and the pelvis during chiropractic treatments for low back pain. Two small force transducers were used to measure hand contact loads, and a specially instrumented force plate table was used for measuring support loads. A doctor of chiropractic delivered fourteen spinal manipulations to the lumbar spines of five subjects during a period of three weeks. The results showed that there are three dimensional loads at each of the four contact points. The loads at the thrusting hands reached as high as 382N. For the stabilizing hands the maximum loads were 160N. The support loads reached as high as 727N at the pelvic support and 660N at the rib cage support. This study reports for the first time data on the loads at each of the hand contact points and the support locations during chiropractic spinal manipulation.

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