PSI - Issue 28

S. Henschel et al. / Procedia Structural Integrity 28 (2020) 1369–1377 S. Henschel et al. / Procedia Structural Integrity 00 (2020) 000–000

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gauge positions or a thorough evaluation of the strain field by means of digital image correlation are believed to improve the analysis. The fractographic analysis revealed a ductile fracture mechanism for all K I / K II ratios. Non-metallic inclusions promoted the ductile fracture. Furthermore, the quantification of the crack tip blunting showed a flattening of the stretch zone. The stretch zone width was una ff ected by an increasing mode II component while the stretch zone height decreased. In addition to the improvements in the strain analysis at the crack tip, acoustic emissions originating from the deformation processes shall be analyzed. Recent experience (Kietov et al. (2019)) shows the suitability of this analysis for detecting damage processes. The aim of these combined techniques is to acquire in-depth knowledge of the damage evolution before and during crack extension in situations where the external force may not be measured accurately. This will be the case when high loading rates are present. Up to now, only loading angles of 0 to 45 ◦ were tested. Tests at larger angles were not successful since the capacity of the machine and the loading device were insu ffi cient. Further modifications of geometry of the specimen and / or loading device are necessary.

Acknowledgments

The authors thank the German Research Foundation (DFG) for its financial support of the investigations at the Collaborative Research Center 920, subprojects C05 and A01. Special thanks to Prof. Hans Albert Richard and Tobias Du ff e (both Paderborn University) for discussing the specimen and the loading device, to Dr.-Ing. Stephan Roth (TU Bergakademie Freiberg) for discussing the finite element analysis and to Prof. Leslie Banks-Sills and Rami Eliasy (both Tel Aviv University) for discussing the results and providing literature.

References

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