The specific heat loss combined with the thermoelastic effect for an experimental analysis of the mean stress influence on axial fatigue of stainless steel plain specimens
The energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, was recently proposed by the authors as fatigue damage index and it was successfully applied to correlate fatigue data obtained by carrying out fully reversed stress- and strain-controlled fatigue tests on...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Gruppo Italiano Frattura
2014-10-01
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| Series: | Fracture and Structural Integrity |
| Subjects: | |
| Online Access: | http://www.gruppofrattura.it/pdf/rivista/numero30/numero_30_art_25.pdf |
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| Summary: | The energy dissipated to the surroundings as heat in a unit volume of material per cycle, Q, was
recently proposed by the authors as fatigue damage index and it was successfully applied to correlate fatigue
data obtained by carrying out fully reversed stress- and strain-controlled fatigue tests on AISI 304L stainless
steel plain and notched specimens. The use of the Q parameter to analyse the experimental results led to the
definition of a scatter band having constant slope from the low- to the high-cycle fatigue regime. In this paper
the energy approach is extended to analyse the influence of mean stress on the axial fatigue behaviour of unnotched
cold drawn AISI 304L stainless steel bars. In view of this, stress controlled fatigue tests on plain
specimens at different load ratios R (R=-1; R=0.1; R=0.5) were carried out. A new energy parameter is defined
to account for the mean stress effect, which combines the specific heat loss Q and the relative temperature
variation due to the thermoelastic effect corresponding to the achievement of the maximum stress level of the
stress cycle. The new two-parameter approach was able to rationalise the mean stress effect observed
experimentally. It is worth noting that the results found in the present contribution are meant to be specific for
the material and testing condition investigated here. |
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| ISSN: | 1971-8993 1971-8993 |