Issue 42

M. Olzak et alii, Frattura ed Integrità Strutturale, 42 (2017) 46-55; DOI: 10.3221/IGF-ESIS.42.06 46 Focused on Mechanical Fatigue of Metals Numerical analysis of the influence of liquid on propagation of a rolling contact fatigue crack Mirosław Olzak, Janusz Piechna Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics, Poland zpk-mo@meil.pw.edu.pl, jpie@meil.pw.edu.pl Paweł Pyrzanowski Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics, Poland pyrzan@meil.pw.edu.pl, http://orcid.org/0000-0003-1015-7645 A BSTRACT . Numerical investigations of the propagation of rolling contact fatigue crack filled by the liquid have been conducted. Two models of fluid – crack interaction have been considered. In the first model called “hydrostatic” the assumption of incompressible, inviscid and weightless liquid was accepted. It was also assumed that due to the wheel load the trapped liquid could not get outside the crack and its volume remained constant until the rising pressure would open up the crack mouth again. On this assumption the analysis has a steady-state character. In the second model it has been assumed that the crack is filled by the viscous, incompressible fluid and the fluid motion as well as the resulting pressure distribution can be represented by one-dimensional form of the Reynolds equation. The method for solving the problem of the coupled motion of liquid and crack faces has been developed and series of calculation were made. The method has been employed for the predicting of crack deformation in the course of wheel rolling. K EYWORDS . Rolling contact fatigue; Fluid viscosity; Stress intensity factor. Citation: Olzak, M., Piechna, J., Pyrzanowski, P., Numerical analysis of the influence of liquid on propagation of a rolling contact fatique crack, Frattura ed Integrità Strutturale, 42 (2017) 46-55. Received: 31.05.2017 Accepted: 08.06.2017 Published: 01.10.2017 Copyright: © 2017 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION he research presented in the paper is part of more comprehensive investigations aimed at understanding the propagation mechanisms of rolling contact fatigue cracks in railway rails. Liquid penetrating the crack interior may be considered as a very important factor affecting the crack propagation. The effect of liquid influence has been already investigated; e.g., M. Kaneta and Y. Murakami [1] considered a 3D model representing a semi-elliptical surface crack situated in the elastic half space. The load had a form of the Hertz stress of