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.

Hybrid Contact Search Algorithm for Wheel/Rail Contact Problems

2008 ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Yoshihiro Suda
Keyword(s):  
Hybrid Algorithm ◽  
Line Search ◽  
Search Algorithm ◽  
Point Contact ◽  
Contact Problems ◽  
Elastic Contact ◽  
Contact Points ◽  
Contact Search ◽  
On Line ◽  
Railroad Vehicle

In this investigation, the on-line and off-line hybrid contact algorithm for modeling wheel/rail contact problems is developed based on the elastic contact formulation. In the tabular contact search used in existing specialized railroad vehicle dynamics codes, contact points are predicted using an assumption of rigid contacts. For this reason, the contact points can be different from those predicted by the on-line based contact search used in general elastic contact formulations. The difference in the contact point becomes significant when flange contacts that have large contact angles are considered. In the hybrid algorithm developed in this investigation, the off-line tabular search is used for treating tread contacts, while the on-line iterative search is used for treating flange contacts. By so doing, a computationally efficient procedure is achieved while keeping accurate predictions of contact points on the wheel flange. Furthermore, the use of the proposed hybrid algorithm can eliminate the use of time-consuming on-line search procedures for the second points of contact as well. Since the location of second points of contact is pre-computed in the contact geometry analysis, the occurrence of two-point contact can be predicted using the look-up table in a straightforward manner. For the two-point contact scenarios encountered in curve negotiations, the online search is used for flange contacts, while the off-line search is used for tread contacts simultaneously. The on-line one-point contact search is also important for flange climb scenarios. It is demonstrated by several numerical examples that the proposed hybrid contact search algorithm can be effectively used for modeling wheel/rail contacts in the analysis of general multibody railroad vehicle systems.

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.

Combined Nodal and Non-Conformal Contact Approach for the Analysis of Turnout Negotiations of Multibody Railroad Vehicles

2011 ◽  
Author(s):  
Hiroyuki Sugiyama ◽  
Takuto Sekiguchi ◽  
Ryosuke Matsumura ◽  
Shunpei Yamashita ◽  
Yoshihiro Suda
Keyword(s):  
Contact Point ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Tabular Data ◽  
Railroad Vehicles ◽  
Contact Points ◽  
Contact Search ◽  
Continuous Surface ◽  
Geometry Analysis ◽  
Conformal Contact

In this investigation, a numerical procedure that can be used for solving complex wheel/rail contact problems in turnout is proposed. In particular, a combined nodal and non-conformal contact approach is developed such that significant jumps in contact points are detected using the nodal search, while the exact location of contact point is then determined with continuous surface parameterizations using non-conformal contact equations. With this combined nodal and non-conformal contact approach for the contact geometry analysis of vehicle/turnout interactions, multiple look-up contact tables can be generated in an efficient way without losing accuracy. Since detailed contact search is performed offline to obtain look-up contact tables, significant changes in contact points in turnout can be efficiently predicted online with tabular data to be interpolated in a standard way. Several numerical examples are presented in order to demonstrate the use of the numerical procedure developed in this investigation.

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.

Modeling Multi-Point Wheel/Rail Contact in the Analysis of Turnout Negotiation of Multibody Railroad Vehicles

2012 ◽  
Author(s):  
Akihiro Terao ◽  
Hiroyuki Sugiyama
Keyword(s):  
Numerical Procedure ◽  
Numerical Results ◽  
Elastic Contact ◽  
Cross Sectional ◽  
Railroad Vehicles ◽  
Curve Negotiation

In this investigation, a numerical procedure that accounts for multipoint contact for the analysis of vehicle/turnout interactions is developed. To this end, the multiple look-up contact table approach that can be used for modeling the change in the rail cross sectional shapes on turnout along the track is generalized for multipoint contact scenarios. The numerical results are compared with those of the online constraint/elastic contact approach for the analysis of curve negotiation first, and then it is demonstrated that the numerical procedure developed in this investigation can be used for predicting the multipoint contact between the wheel and rail for the analysis of vehicle/turnout interactions.

scholarly journals The Indentation Rolling Resistance in Belt Conveyors: A Model for the Viscoelastic Friction

Lubricants ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 58 ◽  
Author(s):  
Nicola Menga ◽  
Francesco Bottiglione ◽  
Giuseppe Carbone
Keyword(s):  
Contact Problem ◽  
Finite Thickness ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Accurate Solution ◽  
Rolling Contact ◽  
Viscoelastic Layer ◽  
Force Coefficient ◽  
Belt Conveyors ◽  
Energy Dissipated

In this paper, we study the steady-state rolling contact of a linear viscoelastic layer of finite thickness and a rigid indenter made of a periodic array of equally spaced rigid cylinders. The viscoelastic contact model is derived by means of Green’s function approach, which allows solving the contact problem with the sliding velocity as a control parameter. The contact problem is solved by means of an accurate numerical procedure developed for general two-dimensional contact geometries. The effect of geometrical quantities (layer thickness, cylinders radii, and cylinders spacing), material properties (viscoelastic moduli, relaxation time) and operative conditions (load, velocity) are all investigated. Physical quantities typical of contact problems (contact areas, deformed profiles, etc.) are calculated and discussed. Special emphasis is dedicated to the viscoelastic friction force coefficient and to the energy dissipated per unit time. The discussion is focused on the role played by the deformation localized at the contact spots and the one in the bulk of the thin layer, due to layer bending. The model is proposed as an accurate solution for engineering applications such as belt conveyors, in which the energy dissipated on the rolling contact of idle rollers can, in some cases, be by far the most important contribution to their energy consumption.

Topology optimization of elastic contact problems using B-spline parameterization

2021 ◽  
Vol 63 (4) ◽  
pp. 1669-1686
Author(s):  
Jiajia Li ◽  
Weihong Zhang ◽  
Cao Niu ◽  
Tong Gao
Keyword(s):  
Topology Optimization ◽  
Contact Problems ◽  
Elastic Contact ◽  
B Spline
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