PSI - Issue 23

Tomáš Vojtek et al. / Procedia Structural Integrity 23 (2019) 481–486 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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5. Conclusions Crack closure was quantified using two d a /d N vs. Δ K curves, the applied curve (stress ratio R is lower than crack closure ratio R cl ) and the effective curve at R = 0.8. A newly proposed formula for description of the crack closure ratio was presented. It fits the experimental data better than previous estimates. The presented methodology allows calibration of parameters describing various mechanisms of crack closure by experimental data and helps to analyse the crack closure mechanisms. After such calibration of only a few parameters, the d a /d N vs. Δ K curves can be reconstructed for an arbitrary stress ratio, including the threshold.

Acknowledgements

This project has received funding from the Research Fund for Coal and Steel under grant agreement No. 747266 (INNOFAT) and partially from the Ministry of Education, Youth and Sports of the Czech Republic under the project m-IPMinfra (CZ.02.1.01/0.0/0.0/16_013/0001823) and the equipment and the base of research infrastructure IPMinfra were used during the research activities.

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