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Flexible wheel/rail contact model for railway vehicle dynamics without pre-calculation
, Article 2007 ASME Rail Transportation Division Fall Conference, Chicago, IL, 11 September 2007 through 12 September 2007 ; 2007 , Pages 87-93 ; 10788883 (ISSN) ; 9780791848005 (ISBN) ; Salehi, S. H ; Jalili, M. M ; Sharif University of Technology
2007
Abstract
An advanced method using progressive concept of geometrical correspondence is applied to create a new wheel/rail contact model based on virtual penetration theory. The geometry and contact mechanism are solved simultaneously because of the independency in a defined correspondence. The model takes the penetrated profiles of wheel and rail and also associated creeps as inputs, and produces driving contact forces as output. The advantage of this model is that it doesn't require pretabulation of rigid contact situation. The method allows calculating flexible, non-elliptical, multiple contact patches during integration of the model. Consequently the rails with substructures can vibrate separately...
Stress Analysis & Life Assessment of Alestum Locomotive's Wheels using Analytical Techniques
, M.Sc. Thesis Sharif University of Technology ; Adib Nazari, Saeed (Supervisor)
Abstract
In this thesis contact problem between wheel and rail has been studied. Also rolling contact fatige (RCF) has been studied in detail. Unlike previous studies that have focused on FEM solution, in this study the problem has been formulated based on analytical methods. Evaluating the loads in wheel-rail contact zone is necessary to find the defects. This thesis presents the evaluation of the stress field inside elastic rolling bodies with an elliptic area of contact. This kind of model can be applied to wheel-rail contact mechanics. The problem has been solved for two main models: with friction and without friction. The results have shown that shear stress reaches the maximum magnitude...
Rolling Contact Fatigue under Influence of Residual Stresses
, M.Sc. Thesis Sharif University of Technology ; Farahi, Gholamhossin (Supervisor)
Abstract
Rolling contact fatigue (RCF) phenomena is important in reducing the fatigue life and increasing the cost of maintenance. Accurate prediction of crack growth on wheels and the influence of residual stresses by FEM modeling can affect the maintenance planning. Therefore, investigation of rolling contact fatigue and its effect on rolling members life seem necessary. The first step to solve a rolling contact fatigue problem is the residual stress determination. In this research, wheel/rail contact is assumed. A bandage wheel with accurate geometry using finite element method is studied. For this purpose, a 3D elastic-plastic finite element model in ANSYS is conducted using model. The...
Considering the Ctability of Train Movement Based on Wagons Arrangement
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor)
Abstract
The main popuse of this Thesis is investigating of the different wagon arrangement effect on stability of the train set. So to gain this goal, one train with 10 wagons has been simulated. The model of the each wagon is Nonlinear with 40 DOF. 3 of the wagons are heavy and make 3 different kinds of arrangement by putting them at first, middle and the end of the train (HLL, LHL and LLH arrangements). Then these three arrangements have been simulated on two differen tracks and conditions, 1st Accelerating on curved track (320 R) with positive slope and 2nd decelerating on curved track with negative slope.We suppose that the contact is singular point and aslso contact equations have bben solved...
A study on the contact ellipse and the contact pressure during the wheel wear through passing the tracks including several sharp curves
, Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 5 , 2018 , Pages 826-833 ; 1728144X (ISSN) ; Farrahi, G. H ; Sohrabpour, S ; Sharif University of Technology
Materials and Energy Research Center
2018
Abstract
Wheel wear has been a concern in the railway for several decades. Studying the form change of the wheel/rail contacts in particular railways consisting of sharp curves helps to identify the risk of severe or catastrophic wear to minimize maintenance costs in order to be competitive in the transportation business. In this paper, the wheel/rail contact was studied on the particular railways. The experimental measurement of wheel profiles was used as an input to Hertz Contact Theory (HCT). It was found that: 1) for these railways the wheel flange is highly worn; 2) a 5th order polynomial function is appropriate to model the wear behavior of the critical wheel; 3) the minimum and maximum contact...