Parametrization of a numerical model for rolling contact calculations

Dominik Otipka

Research output: ThesisMaster's Thesis

Abstract

Cyclic contact between wheel and rail is a critical factor impacting the maintenance and service life of railway components. One key concern is ratcheting, a cyclic plastic deformation occurring under alternating loads. Additionally, changes in wheel and rail geometry influencing the contact surface further affect performance and durability, contributing to potential rail failures. To comprehensively investigate these relationships, Meyer developed a cyclic finite element model plugin [1]. The scope of this thesis is to extend the functionality of the existing plugin to provide a more detailed description of the plastic behavior of materials in cyclic rolling contact phenomena. Specifically, an investigation by using this extended plugin whether ratcheting or plastic shakedown occurs in materials subjected to multiple rolling cycles and various initial conditions takes place. To enable faster calculations, the wheel-rail geometry is simplified to cylindrical forms to create an elliptical contact patch based on Hertzian theory. A major optimization of the extended plugin includes evaluating only a specific selection of rollovers, thereby reducing simulation time. Furthermore, the model structure of the rail is simplified compared to the standard plugin by eliminating the need for sketch insertion, ensuring further optimization and easier creation of a parameter study. Thus, an extended plugin with automated creation of a wheel-rail model is developed, featuring an automated evaluation of contact parameters as well as stresses and strains in the rail. Using the optimized and extended plugin, a parameter study with different variants is conducted and carefully evaluated. The results of this parameter study are summarized in a comprehensive table that serves as a basic reference for future simulations with complex geometries and numerous real-world influences related to contact phenomena.
Translated title of the contributionParametrisierung eines numerischen Modells für Rollkontaktberechnungen
Original languageEnglish
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Daves, Werner, Supervisor (external)
  • Antretter, Thomas, Supervisor (internal)
Award date28 Jun 2024
Publication statusPublished - 2024

Bibliographical note

no embargo

Keywords

  • FEM Simulation
  • Cyclic wheel-rail rolling contact
  • Ratcheting
  • Elastic-plastic material
  • Rolling contact fatigue

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