PSI - Issue 42

12

Author name / Structural Integrity Procedia 00 (2019) 000 – 000

Toru Yagi et al. / Procedia Structural Integrity 42 (2022) 702–713

713

5. Conclusion In this study, the following points are concluded. •

According to the novel experiments which induces pop-ins and a numerical model that is combined FEM analysis and simplified SIF calculation, it was revealed that the current requirement in major standards for pop-in judgment was too conservative. • The previous study of reflected stress wave is not an appropriate theory to describe the pop-in crack arrest. • The pop-in crack arrests by the closing effect of the side ligament which comes from the fact that the pop-in crack is a tunnel crack. The width of the local brittle zone is an important parameter for the pop-in standard. • New proposal of the judgment criterion is that if the width of the LBZ is less than 2 mm, pop-in of less than “10%” of the load drop can be ignored. • The possibility to express the pop-in crack by the FEM analysis incorporating the idea of energy dissipation is suggested.

References

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