PSI - Issue 57

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 57 (2024) 152–160

Fatigue Design 2023 (FatDes 2023) Fatigue Behaviour of Cord Rubber Composite Materials in Air Spring Bellows of Rail Vehicles Torggler J. a *, Buzzi C. a , Leitner M. a , Faethe T. b , Müller H. c a Graz University of Technology, Institute of Structural Durability and Railway Technology, Inffeldgasse 25/D, 8010 Graz, Austria Abstract Bogies of rail vehicles for passenger coaches and traction units commonly contain air spring systems as secondary spring stages. In the development and design of spring stages, it is necessary to ensure precise knowledge about the material properties and fatigue behaviour of the air spring bellows. The aim of this work is to systematically investigate the damage mechanisms evaluated at air spring bellows on sample level and to analyse the fatigue strength of the base material under different load conditions. The specially developed small-scale sample is biaxially loaded and different layups are examined at varying load levels. In the tests with different parameters, an increase in the mean value of the longitudinal displacement by 20 % has proved to act as a suitable failure criterion. In addition to the purely optical damage analysis, micro computed tomography analysis was carried out. In this study, four layered samples with a fibre angle of ±15, ±25 and ±35 degrees in respect to the longitudinal direction are examined. A global evaluation of the service life tests reveals that under comparable load conditions, the fibre angle exhibits a clear influence on the fatigue strength. The increase of 10 degree in fibre angle roughly results in a 15 % reduction of the tolerable lateral displacement amplitude at a number of fifty thousand load-cycles which commonly acts as design lifetime. In a second step, a local analysis based on an analytical approach is presented. With the help of the fibre strain amplitude calculated, all fatigue test data points can be unified to a master S/N-curve leading to an elaborated design model of cord rubber composite materials used in air spring bellows of rail vehicles. With the help of the presented methodology utilizing the developed representative small-scale sample testing procedure and evaluation approach, a time- and cost-efficient fatigue design is facilitated. b Siemens Mobility Austria GmbH Bogies, Eggenberger Straße 31, 8020 Graz, Austria c GMT Gummi-Metall-Technik GmbH, Liechtersmatten 5, 77815 Bühl, Germany

* Corresponding author. Tel.: +43 316 873 - 1369; fax: +43 316 873 - 1362. E-mail address: julian.torggler@tugraz.at

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2023 organizers 10.1016/j.prostr.2024.03.018