PSI - Issue 13

Johannes Tlatlik et al. / Procedia Structural Integrity 13 (2018) 243–248 Johannes Tlatlik, Dieter Siegele / Structural Integrity Procedia 00 (2018) 000 – 000

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testing temperature, which is in agreement with the fractographic observations made in Figure 1 b). In addition, the model modification is also able to consider different arrest probabilities connected to a change in crack tip loading rate (Figure 2 a)), because this is conceived in the crack energy γ crack ( σ I , Δ a ).

7. Conclusions

The fracture behavior under dynamic loading is strongly influenced by local crack arrest incidences. This effect is responsible for a change of fracture probability compared to quasi-static loading. The probability of local crack arrest increases with increasing temperature and decreasing crack tip loading rate. The micromechanical models derived for quasi-static loading reveal discrepancies compared to experimental findings even if adiabatic processes regarding heat generation and conduction are thoroughly respected. Therefore, a modified model considering local crack arrest is presented. The proposed micromechanical model modification greatly improves the physical background of cleavage fracture models, and is in accordance with the fractographic observations. Ultimately, the numerical predictability of cleavage fracture at elevated loading rates is significantly improved. Acknowledgements

The research project “Micromechanically Based Cleavage Fracture Model for the Characterization of Fracture Behavior under Dynamic Loading” is funded by the German Federal Ministry for Economic Affairs and Energy (BMWi, Project No. 1501495) on the basis of a decision by the German Bundestag.

References

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