PSI - Issue 42

Kai Donnerbauer et al. / Procedia Structural Integrity 42 (2022) 738–744 Kai Donnerbauer / Structural Integrity Procedia 00 (2019) 000 – 000

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application case in mind. Another advantage when pursuing this approach may be the better ability to get this NDT data accessed when compared to mechanical stress or strain data. The short time evaluation procedure StrainLife in combination with NDT data provides good results, even for strain-controlled loading in the low cycle fatigue regime. Since degradation is a characteristic of fatigue being expressed as damage, it is essential to define what degradation represents physically and how the physically sensitive parameters could be measured through NDT. This needs to be done on a material’s level first before moving to a component level. Currently mostly cracks and their size are considered in view of degradation but establishing a better understanding for a degradation or damage criterion for a material or structure could help to further improve reliability of fatigue data generated from short time evaluation procedures like StrainLife and also for evaluating components in service nondestructively. Going forward, instrumented component tests are currently being planned to transfer the presented NDT methods and StrainLife onto pipes under realistic operating conditions. Acknowledgements This research was funded by the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (Bundesministerium für Umwelt, Naturschutz, nukleare Sicherheit und Verbraucherschutz, BMUV) , within the framework of the joint project “Microstructure -based determination of the maximum service life for co rrosion fatigue loaded materials and components of nuclear technology”, part II, funded grant numbers 1501610A, 1501610B, 1501610C, 1501610D and RS1594E. The authors thank the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) and the Ministry of Culture and Science of North Rhine-Westphalia (Ministerium für Kultur und Wissenschaft des Landes Nordrhein Westfalen, MKW NRW) for their financial support within the Major Research Instrumentation Program (FIB-SEM Zeiss XB550 L, 386509496, INST 212/402-1 FUGG). References Acosta, R., Heckmann K., Sievers, J., Schopf, T., Bill, T., Starke, P., Donnerbauer, K., Lücker, L., Walther, F., Boller, C., 2021. Microstructure based lifetime assessment of austenitic steel AISI 347 in view of fatigue, environmental conditions and NDT. Applied Sciences 11, 23, 11214. Acosta, R., Starke, P., Boller, C., Jamrozy, M., Klein, M., Knyazeva, M., Walther, F., Heckmann, K., Sievers, J., Schopf, T., Schuler, X., 2018. Use of non-destructive testing methods for microstructure-based residual life assessment of aging metallic materials and components in power engineering (in German), ndt.net 9, 1-12. Basquin, O. H., 1910. The exponential law on endurance tests. Proceedings of the 13th Annual Meeting, Atlantic City, USA, 625 – 630. Bill, T., Acosta, R., Boller, C., Donnerbauer, K., Lücker, L., Walther, F., Heckmann, K., Sievers, J., Schopf, T., Weihe, S., Starke, P., 2021. A short-time approach for fatigue life evaluation of AISI 347 steel for nuclear power energy applications. Applied Sciences 11, 23, 11405. Coffin, L. F., 1954. A study of the effects of cyclic thermal stresses on a ductile metal. Journal of Fluids Engineering 76, 6, 931 – 949. Dobmann, G., 2017. NDT for characterizing ageing and degradation of nuclear power plant materials – Fatigue and irradiation. Proceedings of 2017 IEEE Far East Forum on Nondestructive Evaluation/Testing - New Technology and Application, Xian, China, 286 – 291. Jinlong, L., Hongyun, L., 2013. Effects of strain and strain-induced α′ -martensite on passive films in AISI 304 austenitic stainless steel. Materials Science and Engineering C 34, 484 – 490. Klein, M., Starke, P., Nowak, D., Boller, C., Walther, F., 2016. Separation of surface, subsurface and volume fatigue damage effects in AISI 348 steel for power plant applications. Materials Testing 58, 601 – 607. Li, H., 2011. Studies on the correlation between natural magnetization and mechanical damages of an austenitic stainless steel. Proceedings of the 18th International Conference on Nuclear Engineering (ICONE-18), Xian, China, 553 – 557. Manson, S.S., 1953. Behavior of materials under conditions of thermal stress. Heat Transfer Symposium, Ann Arbor, USA, 9 – 75. Morrow, J., 1964. Cyclic plastic strain energy and fatigue of metals. Internal Friction, Damping and Cyclic Plasticity, STP 378, 45 – 87.