Publication Date


Document Type


First Advisor

Fallahi, Behrooz

Degree Name

M.S. (Master of Science)

Legacy Department

Department of Mechanical Engineering


Mechanical engineering; Engineering


Computation of the common normals between wheelset and rail is an important problem in simulation of wheel/rail interaction. Its computational robustness and efficiency is the key in any successful application of simulation for railroad vehicle study. Current approaches use Newton's method. Newton's method converges to only one local minimum. But all common normal must be computed. Therefore, it is necessary to generate one estimate for each common normal. In this study, the large curvature of the track is used to devise a scheme to identify and compute the estimate of each common normal. Newton's method will fail if the Jacobean of system of equations governing the location of common normal become ill conditioned. In this study, computation of a common normal will be formulated as an optimization problem. Trust Region Method which is more robust, will be used. Two implementations of Trust Region Method will be used and their efficiency will be compared to that of Newton's Method.


Advisors: Behrooz Fallahi.||Committee members: Sachit Butail; Jenn-Terng Gau.||Includes illustrations.||Includes bibliographical references.


32 pages




Northern Illinois University

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