Un modelo integral para describir la influencia de la frecuencia de ensayo sobre los resultados de fatiga
- A. Fernández Canteli 1
- E. Castillo E. 2
- S. Blasón 3
- G. Khatibi 4
- B. Czerny 4
- M. Zareghomsheh 4
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1
Universidad de Oviedo
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- 2 Real Academia de Ingeniería y Real Academia de Ciencias de España
- 3 BAM, Berlin, Alemania
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4
Vienna University of Technology
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ISSN: 2792-4246
Year of publication: 2022
Issue: 3
Pages: 83-88
Type: Article
More publications in: Revista española de mecánica de la fractura
Abstract
The influence of the frequency is analyzed as a viscoelastic hardening effect of the material that leads simultaneously to a reduction of the nominal values of the maximum stress, σM, and the stress ratio, R, applied during the test for increasing frequency. In this way, the σM-R-f-N model, in which the maximum voltage is the primary reference variable while the stress ratio, R, and the frequency, f, are the secondary variables, is reduced to the three-dimensional probabilistic σM-RN model, recently developed. The nominal σM-R pairs applied during the test are transformed into effective σM-R pairs that can be evaluated as pertaining to a single sample regardless of the test frequency and stress ratio. In addition, the model defines a normalized variable V which represents a measure of the accumulated damage when the specimen is subjected to a variable load history, allowing the evolution of the probability of failure to be estimated as a function of the applied load. The model is validated when applied to a wide experimental fatigue program carried out on high purity aluminum alloy wires, Al_H11, used in the interface of insulated gate bipolar transistors (IGBT) under three different frequencies (2, 20 and 200 Hz).