Fatigue life assessment of a railway wheel material under HCF and VHCF conditions

Soares, Henrique; Costa, Patrícia; Freitas, M.

doi:10.1051/matecconf/201816509003

Cited by 11 publications

(10 citation statements)

References 5 publications

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“…7, the crack initiation point was always located at the specimen's surface. It should also be mentioned that the percentage of fatigue area is much lesser in comparison to uniaxial fatigue specimens obtained by the research [7].…”

Section: Fig 6 S-n Resultsmentioning

confidence: 75%

“…Very few examples of multiaxial ultrasonic fatigue testing can be found, one worthy mention is the test created by Palin-Luc able to achieve biaxial bending stresses [6]. In this study the fatigue analysis of a worn out railway wheel is performed, focuses on the development and testing of an ongoing research of a multiaxial tension/torsion ultrasonic fatigue machine [7,8,9].…”

Section: Introductionmentioning

confidence: 99%

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Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel

et al. 2019

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Ultrasonic fatigue testing is a relative recent fatigue methodology that uses resonant principles for the induction of stress cycles in a specific designed material specimen. This experimental method can apply very high cycle frequency, the most common frequency being 20 kHz, and was created with the main purpose of studying material fatigue life in the Very High Cycle Fatigue regime between 10 7 and 10 9 cycles with a higher performance of time and energy wise in comparison to conventional servo-hydraulic machines. In this study an improvement of an already built multiaxial ultrasonic fatigue machine in the Instituto Superior Técnico laboratories was carried out to specific designed specimens and afterwards a fatigue study was made for a material of a worn-out railway wheel. The particular design of the specimen was achieved by numerical and experimental analysis based on previous experiments and components. Thermographic imaging and the application of rosette strain gauges to the main throat of the specimens were conducted in order to validate the improved specimen design and to understand the real induced stresses on the specimen. Afterwards fatigue tests were conducted for several specimens for a wide range of stresses with a stress ratio R=-1 and an axial vs shear stress ratio of around 0.58. Results were analysed and fracture analysis was also carried out.

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Section: Fig 6 S-n Resultsmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel

et al. 2019

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“…It is composed of three 'throats', where the central one is where maximum tension/torsion are achieved [15] and where fatigue failure is expected. Several steel tension/torsion specimens were machined from a railway wheel's rim [89][90][91]. When testing these particular specimens in UFT machines, they do not achieve complete failure, i.e., split up into two pieces.…”

Section: Tension/torsion Ultrasonic Fatigue Testingmentioning

confidence: 99%

Review of Multiaxial Testing for Very High Cycle Fatigue: From ‘Conventional’ to Ultrasonic Machines

et al. 2020

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Fatigue is one of the main causes for in service failure of mechanical components and structures. With the development of new materials, such as high strength aluminium or titanium alloys with different microstructures from steels, materials no longer have a fatigue limit in the classical sense, where it was accepted that they would have ‘infinite life’ from 10 million (107) cycles. The emergence of new materials used in critical mechanical parts, including parts obtained from metal additive manufacturing (AM), the need for weight reduction and the ambition to travel greater distances in shorter periods of time, have brought many challenges to design engineers, since they demand predictability of material properties and that they are readily available. Most fatigue testing today still uses uniaxial loads. However, it is generally recognised that multiaxial stresses occur in many full-scale structures, being rare the occurrence of pure uniaxial stress states. By combining both Ultrasonic Fatigue Testing with multiaxial testing through Single-Input-Multiple-Output Modal Analysis, the high costs of both equipment and time to conduct experiments have seen a massive improvement. It is presently possible to test materials under multiaxial loading conditions and for a very high number of cycles in a fraction of the time compared to non-ultrasonic fatigue testing methods (days compared to months or years). This work presents the current status of ultrasonic fatigue testing machines working at a frequency of 20 kHz to date, with emphasis on multiaxial fatigue and very high cycle fatigue. Special attention will be put into the performance of multiaxial fatigue tests of classical cylindrical specimens under tension/torsion and flat cruciform specimens under in-plane bi-axial testing using low cost piezoelectric transducers. Together with the description of the testing machines and associated instrumentation, some experimental results of fatigue tests are presented in order to demonstrate how ultrasonic fatigue testing can be used to determine the behaviour of a steel alloy from a railway wheel at very high cycle fatigue regime when subjected to multiaxial tension/torsion loadings.

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“…Such machines can induce cycling stresses with frequencies of around 20 kHz or even higher. Such tests could only initially apply uniaxial tension-compression, bending and torsion tests [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic fatigue experiments with biaxial cruciform specimens

et al. 2019

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Fatigue studies of materials in simple or complex loading systems for any given lifetime is object of continuous research. This is due to the advancements on mechanical and structural components, as well as for new and innovative materials, which implies the knowledge of a materials response to all dynamic loads. The fatigue failure regime beyond what was once considered to be the fatigue limit (infinite life) is characterized between 10 7 and 10 9 , known as Very High Cycle Fatigue regime. Due to the time consuming and wide energy consumption of conventional fatigue testing for such regime, fatigue tests under ultrasonic actuators are being used, capable of applying the dynamic loads at around 20 kHz. Nowadays, several variants of ultrasonic fatigue tests were already proposed and tested but it is still a somewhat limited fatigue test if compared to the conventional servo-hydraulic fatigue testing machines of general use. In this study, biaxial in plane stresses are induced in specially designed cruciform specimens with ultrasonic fatigue testing resonant principals. Two geometries were numerically analysed, manufactured and experimentally tested, the in-phase tension-tension (T-T) specimen and the out-of-phase compression-tension (C-T) specimen. All specific designed geometries go under a thorough numerical and several experiments analysis for their validation. The specimens showing a correct and as intended behaviour are led to failure.

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Fatigue life assessment of a railway wheel material under HCF and VHCF conditions

Cited by 11 publications

References 5 publications

Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel

Ultrasonic fatigue testing under multiaxial loading conditions on a railway wheel

Review of Multiaxial Testing for Very High Cycle Fatigue: From ‘Conventional’ to Ultrasonic Machines

Ultrasonic fatigue experiments with biaxial cruciform specimens

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