PSI - Issue 25

ScienceDirect Structural Integrity Procedia 00 (2019) 000–000 Structural Integrity Procedia 00 (2019) 000–000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia

www.elsevier.com/locate/procedia

Procedia Structural Integrity 25 (2020) 445–453

© 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers Abstract Fatigue is one of the main causes for in service failure of mechanical components and structures. The need for the weight reduction of components and a growing need for greater lifespans of equipment, forced the understanding of the fatigue behaviour of materials under multiaxial loading cycles and increased number of loading cycles. It is generally recognized that multiaxial stresses occur in many full-scale structures, being rare the occurrence of pure uniaxial stress states. Nevertheless, the high cost of fatigue materials testing under multiaxial loading and for very high number of cycles, was a serious drawback for the research under these testing conditions. This study is a description of the present status of fatigue testing machines working at a frequency of 20 kHz, and the research that can be carried out in order to perform multiaxial fatigue tests under bi-axial stress states and very high cycle fatigue. Special emphasis will be given to the performance of multiaxial fatigue tests under axial/torsion and in plane bi-axial testing using low cost piezo-electric transducers either in classical cylindrical or in cruciform specimens and associated instrumentation. Together with the description of the testing machines, experimental results of fatigue tests will be presented in order to compare the behaviour of a metallic material from a Railway wheel under multiaxial tension/torsion at very high cycle fatigue. Abstract Fatigue is one of the main causes for in service failure of mechanical components and structures. The need for the weight reduction of components and a growing need for greater lifespans of equipment, forced the understanding of the fatigue b haviour of materials under multiaxial loading ycles and increased number of loading cycles. It is generally re og ized that multiaxial stresses occur in many full-scale structures, bei g rare the occurrence of pure uniaxial stress states. Nevertheles , the high cost of fatigue materials testi g under multiaxial l a i and for very high numb r of cycles, was a serious drawback for the research under thes testi conditions. This study is a description of the present status of fatigue testing machines working at a frequency of 20 kHz, and the research that can be carried out in order to perform multiaxi l fatigue tests under bi-axial str ss states and very high cycle fatigue. Special emphasis will be given t the performa ce of multiaxial fati ue tests under axial/torsion a in plane bi-axi l testing using low cost piezo-electric transducers either in clas ical cylindric l or in cruciform specimens and associated instrum ntation. Together with the description of the testing machines, xperim ntal results of fatigue tests will be presented in rder to compare the behaviour of a metallic material from a Railway wheel under multiaxial tension/torsion at very igh cycle fatigue. Keywords: Piezoelectric fatigue testing machines;Biaxial Fatigue; Cylindricaland cruciform specimens; Very High Cycle Fatigue 1st Virtual Conference on Structural Integrity - VCSI1 Tension/torsion ultrasonic fatigue testing on a railway wheel Pedro R. da Costa a ,Henrique Soares a , Luís Reis a *, Manueal de Freitas a,b 1st Virtual Conference on Structural Integrity - VCSI1 Tension/torsion ultrasonic fatigue testing on a railway wheel Pedro R. da C sta a ,Henrique Soares a , Luís Reis a *, Manueal de Freitas a,b a IDMEC, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa, 1049-001 Lisboa, Portugal b Atlântica, Escola Universitária, Fabrica da Pólvora de Barcarena, 2730-036 Barcarena Portugal a IDMEC, Instituto Superior Técnico, Av. Rovisco Pais, Lisboa, 1049-001 Lisboa, Portugal b Atlântica, Escola Universitária, Fabrica da Pólvora de Barcarena, 2730-036 Barcarena Portugal

Keywords: Piezoelectric fatigue testing machines;Biaxial Fatigue; Cylindricaland cruciform specimens; Very High Cycle Fatigue

* Corresponding author. Tel.: +351 966 415 585 E-mail address: luis.g.reis@tecnico.ulisboa.pt * Corresponding author. Tel.: +351 966 415 585 E-mail address: luis.g.reis@tecnico.ulisboa.pt

2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 10.1016/j.prostr.2020.04.050 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers 2452-3216 © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the VCSI1 organizers