Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-25608 Vortrag Zerbst, Uwe Anmerkungen zur Auslegung und zum sicheren Betrieb von Radsatzwellen aus der Sicht von Betriebsfestigkeit und Bruchmechanik 2012 7. Fachtagung ZfP im Eisenbahnwesen 7. Fachtagung ZfP im Eisenbahnwesen Wittenberge, Germany 2012-03-20 2012-03-22 2016-02-19 OPUS4-25595 Vortrag Zerbst, Uwe Some Aspects of Safe-Life and Damage Tolerance of Railway Axles 2012 ESIS TC 24 Workshop of "Improving Lifetime and NDT" ESIS TC 24 Workshop of "Improving Lifetime and NDT" Milan, Italy 2012-03-30 2012-03-30 2016-02-19 OPUS4-26363 Beitrag zu einem Tagungsband Komann, Steffen; Kiyak, Yusuf; Wille, Frank; Zerbst, Uwe; Weber, Mike; Klingbeil, Dietmar Assessment of ductile cast iron fracture mechanics analysis within licensing of German transport packages New York American Society of Mechanical Engineers 2012 PVP2012 - Proceedings of the ASME 2012 Pressure vessels & piping division conference ASME 2012 Pressure vessels & piping division conference Toronto, Ontario, Canada 2012-07-15 2012-07-19 PVP2012-78213, 1-7 2016-02-19 OPUS4-28620 Beitrag zu einem Tagungsband Heckel, Thomas; Zerbst, Uwe Einfluss von Save Life- und Schadenstoleranzkonzepten auf die ZfP von Eisenbahnradsatzwellen Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP) 2013 DGZfP-Jahrestagung 2013 978-3-940283-49-8 DGZfP-Jahrestagung 2013 Dresden, Germany 2013-05-06 2013-05-08 Mi.1.A.1 1 7 2016-02-20 OPUS4-25022 Beitrag zu einem Tagungsband Komann, Steffen; Kiyak, Yusuf; Wille, Frank; Zerbst, Uwe; Weber, Mike; Klingbeil, Dietmar Assessment of ductile cast iron fracture mechanics analysis within licensing of German transport packages In the approval procedure of transport packages for radioactive materials, the mechanical and thermal safety assessment is carried out in Germany by competent authority BAM. In recent years BAM was involved in several licensing procedures of new spent fuel and HLW package designs, where the cask body was made of Ductile Cast Iron (DCI). According to IAEA regulations package designs have to fulfill requirements for specific conditions of transport. Type B(U) packages must withstand the defined accident conditions of transport. The temperature range from -40°C up to the operational temperature has to be considered. For the cask material DCI, it is necessary to determine the brittle fracture behavior. The German guideline BAM-GGR 007 defines requirements for the fracture mechanics of DCI. Due to complex structure of the cask body and the dynamic loading a fracture mechanical assessment in an analytical kind is not always possible. Experience of recent design approval procedures show that the application of numerical calculations are applicable to determine the fracture mechanical load in the cask body. At the first step a numerical analysis has to be done to identify the loading state at the whole cask body. Secondly an analysis of a detail of the cask body is made considering the displacement boundary conditions of the global model. An artificial flaw is considered in this detailed model to calculate the fracture mechanical loading state. The finite element mesh was strongly refined in the area of flaw. The size of the artificial flaw is characterized by the ultrasonic inspection used for the quality assurance of the package. The applicant developed additional analysis tools for calculation of stress intensity factor and/or J-Integral. The assessment approach by BAM led to the decision to develop own tools to the possibility for independent check of the results. The paper describes the authority assessment approach for the DCI fracture mechanics analysis. The validation procedure incl. the development of own tools is explained. BAM developed a post-processor called JINFEM to determine the fracture mechanical loads. The regulatory 1 m puncture bar drop test is used to give an example of the assessment procedure. Institute of Nuclear Materials Management (INMM) 2011 52nd INMM Annual meeting (Proceedings) 52nd INMM Annual meeting Palm Desert, CA, USA 17.07.2011 21.07.2011 1 10 2016-02-19 OPUS4-27355 Vortrag Zerbst, Uwe Fracture and Crack Propagation in Weldments. A Fracture Mechanics Perspective 2012 ESIS TC 1 Workshop on "Structural Integrity of Weldments" ESIS TC 1 Workshop on "Structural Integrity of Weldments" Freiburg, Germany 2012-12-06 2016-02-20 OPUS4-27356 Vortrag Zerbst, Uwe Anmerkungen zur Auslegung und zum sicheren Betrieb von Radsatzwellen aus der Sicht von Betriebsfestigkeit und Bruchmechanik 2012 Schienenfahrzeugtagung 2012 (Rad-Schiene) Schienenfahrzeugtagung 2012 (Rad-Schiene) Dresden, Germany 2012-09-12 2012-09-14 2016-02-20 OPUS4-27595 Vortrag Zerbst, Uwe IBESS - ein DFG/AiF-Clusterprojekt: Integrale Bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen 2013 45. Tagung des DVM-Arbeitskreises Bruchvorgänge 45. Tagung des DVM-Arbeitskreises Bruchvorgänge Berlin, Germany 2013-02-19 2013-02-20 2016-02-20 OPUS4-27597 Vortrag Zerbst, Uwe Anwendung bruchmechanischer Werkstoffkennwerte in der Bauteilbewertung. Grundlagen, spezielle Aspekte, Regelwerke 2013 Fortbildungsseminar des DVM AK Bruchvorgänge Fortbildungsseminar des DVM AK Bruchvorgänge Berlin, Germany 2013-02-18 2013-02-18 2016-02-20 OPUS4-25456 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Hellmann, C. An analytical fracture mechanics model for estimation of S-N curves of metallic alloys containing large second phase particles An analytical fracture mechanics model for predicting the finite life fatigue strength of components is presented which combines a number of well established and newly developed approaches such as Murakami's and McEvily's approach for describing the transient behaviour of crack closure of short cracks, the analytical (long) crack closure function of Newman which became part of the widely used NASGRO approach, the R6 procedure, a method for improving the ligament yielding correction f(Lr ) of R6 proposed by the authors of the present paper and other elements. Basic assumption is the preexistence of initial flaws such that the crack initiation or nucleation stage is small and can be neglected. The application of the model is demonstrated for small tension plates of aluminium Al 5380 H321 with artificial initial defects generated by FIB technology, the size of which was fixed on the basis of fractographic investigations on broken, smooth specimens. Kidlington Elsevier Science 2012 Engineering fracture mechanics 82 115 134 10.1016/j.engfracmech.2011.12.001 2016-02-19 OPUS4-27779 Zeitschriftenartikel Zerbst, Uwe; Beretta, S.; Köhler, G.; Lawton, A.; Vormwald, M.; Beier, H.T.; Klinger, Christian; Cerný, I.; Rudlin, J.; Heckel, Thomas; Klingbeil, Dietmar Safe life and damage tolerance aspects of railway axles - A review The paper gives an overview on safe life and damage tolerance methods applied to railway axles. It describes failure scenarios due to fatigue crack initiation and propagation. Besides common aspects of design, specific features such as corrosion and impact damage from flying ballast are discussed which may reduce the fatigue strength of axles during service. Potential effects of non-metallic inclusions from the steel manufacturing process are addressed in the context of the very high number of loading cycles railway axles are designed for. With respect to damage tolerance general lines of fracture mechanics residual lifetime analyses are introduced. More specific discussion is provided on aspects such as the threshold value of fatigue crack propagation and reliability aspects of non-destructive inspection. Kidlington Elsevier Science 2013 Engineering fracture mechanics 98 214 271 10.1016/j.engfracmech.2012.09.029 2016-02-20 OPUS4-29537 Beitrag zu einem Tagungsband Zerbst, Uwe; Madia, Mauro Yu, S.; Feng, X.-Q. Fracture mechanics model for predicting fracture strength of metallic alloys containing large second phase particles An analytical fracture mechanics model for predicting the finite life fatigue strength of components is presented which Combines a number of well established and newly developed approaches such as Murakami's and McEvily's approach for describing the transient behaviour of crack closure of short cracks, the analytical (long) crack closure function of Newman, the R6 procedure modified by a method for improving the ligament yielding correction proposed by the authors and other elements. Basic assumption is the preexistence of initial flaws such that the crack initiation or nucleation stage is small and can be neglected. The application of the model is demonstrated for small tension plates of aluminium Al 5380 H321 with artificial initial defects generated by FIB technology, the size of which was fixed on the basis of fractographic investigations on broken, smooth specimens. 2013 ICF13 - 13th International conference on fracture (Proceedings) 978-988-12265-2-5 ICF13 - 13th International conference on fracture Beijing, China 16.06.2013 21.06.2013 1 12 2016-02-20 OPUS4-29501 Vortrag Zerbst, Uwe Bruchmechanik an Schweißverbindungen 2013 Gemeinschaftssitzung DVS-AGQ12, DVM AG Bruchmechanik an Schweißverbindungen und IBESS, BAM Gemeinschaftssitzung DVS-AGQ12, DVM AG Bruchmechanik an Schweißverbindungen und IBESS, BAM Berlin, Germany 2013-11-26 2013-11-26 2016-02-20 OPUS4-29651 Beitrag zu einem Tagungsband Klingbeil, Dietmar; Zerbst, Uwe; Klinger, Christian Yu, S.; Feng, X.-Q. Safe life and damage tolerance concepts of railway axles On July 9, 2008 a high speed train derailed in Cologne main Station, Germany at a low speed because an axle was broken. Fortunately, the derailment happened at a low speed so that nobody was injured. The reason for the broken axle was investigated and it turned out that most likely large inclusions located shortly undemeath the surface in a T-transition were the origin of the final crack. Basing on that result, a systematic investigation on existing safety assessments of railway axles was performed. This results in an analysis of the production process of axles and in a critical review of existing of existing assessments. Improvements and future developments are outlined. 2013 ICF13 - 13th International conference on fracture (Proceedings) 978-988-12265-2-5 ICF13 - 13th International conference on fracture Beijing, China 16.06.2013 21.06.2013 1 10 2016-02-20 OPUS4-22329 Beitrag zu einem Sammelband Zerbst, Uwe; Ainsworth, R. A.; Madia, Mauro Klingbeil, D.; Vormwald, M.; Eulitz, K.-G. Reference load versus limit load in engineering flaw assessment: A proposal for a hybrid analysis option The net section limit load FY is a key input parameter for the accuracy of any elastic-plastic flaw assessment procedure of the R6 type. Unfortunately available limit load solutions are of variable quality since they have been obtained over decades by different methods. As a consequence the results of the fracture analyses such as the critical load or crack size are limited in their accuracy and are often significantly conservative. A further problem is that common limit load solutions based on ligament yielding are inadequate in a number of cases even for through crack configurations and should be replaced by some kind of local yielding solutions. In the present paper a simple and straightforward reference load definition is proposed instead of the limit load which strictly corresponds to a ligament yielding parameter Lr = 1 in the R6 Routine and similar approaches such as SINTAP and FITNET. This can be determined by finite element simulation for any geometry. In addition to a previous study on thin wall notched plates the method is applied to plates containing shallow semi-elliptical surface cracks. The results demonstrate that the approach provides a suitable extension and improvement of the existing methods. Deutscher Verband für Materialforschung und -prüfung e.V. (DVM) 2010 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale (Proceedings) 978-3-00-031802-3 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale Dresden, Germany 2010-08-30 2010-09-03 Paper 81 1 11 2016-02-19 OPUS4-22287 Vortrag Zerbst, Uwe Reference load versus limit load in engineering flaw assessment. A proposal for a hybride analysis option 2010 18th European Conference on Fracture 18th European Conference on Fracture Dresden, Germany 2010-08-30 2010-09-03 2016-02-19 OPUS4-22837 Beitrag zu einem Tagungsband Madia, Mauro; Riesch-Oppermann, H.; Zerbst, Uwe; Beretta, S. Ein Konzept für die probabilistische bruchmechanische Bauteilbewertung Deutscher Verband für Materialforschung und -prüfung e.V. 2010 42. Tagung des DVM-Arbeitskreises Bruchvorgänge - Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen 42. Tagung des DVM-Arbeitskreises Bruchvorgänge - Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen Paderborn, Deutschland 2010-02-23 2010-02-24 51 60 2016-02-19 OPUS4-22843 Beitrag zu einem Sammelband Madia, Mauro; Riesch-Oppermann, H.; Zerbst, Uwe; Beretta, S. Klingbeil, D.; Vormwald, M.; Eulitz, K.-G. A new full-probabilistic framework for the structural integrity assessment of structures containing cracks Deutscher Verband für Materialforschung und -prüfung e.V. (DVM) 2010 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale (Proceedings) 978-3-00-031802-3 18th European conference on fracture (ECF 18) - Fracture of materials and structures from micro to macro scale Dresden, Germany 2010-08-30 2010-09-03 C.02.1-3 / #306 1 10 2016-02-19 OPUS4-27278 Beitrag zu einem Tagungsband Zerbst, Uwe; Madia, Mauro; Hellmann, D. Fracture mechanics model for predicting fatigue strength of metallic alloys containing large second phase particles European Structural Integrity Society (ESIS) 2012 ECF 19 - 19th European conference on fracture - Fracture mechanics for durability, reliability and safety 978-5-905576-18-8 ECF 19 - 19th European conference on fracture - Fracture mechanics for durability, reliability and safety Kazan, Russia 2012-08-26 2012-08-31 Proceeding-ID 116 1 14 2016-02-20 OPUS4-27279 Zeitschriftenartikel Zerbst, Uwe; Ainsworth, R. A.; Madia, Mauro Reference load versus limit load in engineering flaw assessment: A proposal for a hybrid analysis option The net section limit load FY necessary for assessment at static loading is a key input for the accuracy of any elastic–plastic flaw assessment procedure of the R6 type. Unfortunately available limit load solutions are of variable quality since they have been obtained over decades by different methods. As a consequence the results of the fracture analyses such as the critical load or crack size are limited in their accuracy and are often significantly conservative. Further, common limit load solutions based on ligament yielding are inadequate in a number of cases even for through crack configurations and should be replaced by some kind of local yielding solutions. In the present paper a simple and straightforward reference load definition is proposed instead of the limit load which strictly corresponds to a ligament yielding parameter Lr = 1 in the R6 Routine and similar approaches such as the European SINTAP and FITNET methods. This can be determined by finite element simulation for any geometry. In addition to a previous study on thin wall notched plates the method is applied to plates containing shallow semi-elliptical surface cracks. The results demonstrate that the approach provides a suitable extension and improvement of the existing methods. Kidlington Elsevier Science 2012 Engineering fracture mechanics 91 62 72 10.1016/j.engfracmech.2011.10.018 2016-02-20 OPUS4-29715 Zeitschriftenartikel Zerbst, Uwe; Klinger, Christian; Klingbeil, Dietmar Structural assessment of railway axles - A critical review The safety assessment of railway axles is based on a two-stage approach: fatigue strength design and regular inspections which, in terms of a general safety philosophy refer to safe-life and damage tolerance concepts. Starting with a recent failure case, a broken axle of a German high speed train, a discussion is presented on issues of both safety levels. These include ideas for finite life design, the treatment of in-service effects on the fatigue strength due to flying ballast damage and corrosion pits, the effect of corrosion on fatigue crack initiation and propagation, potential effects of non-metallic inclusions in steels, the way to detect them by quality control measures and reliability aspects of non-destructive testing with respect to the detection of fatigue cracks. Proposals are made how the safety level could be further improved. Oxford Elsevier Science Publ. 2013 Engineering failure analysis 35 Special issue on ICEFA V- Part 1 54 65 2016-02-20 OPUS4-29738 Vortrag Zerbst, Uwe Referenzlastlösungen für die Ermittlung der elastisch-plastischen Rissspritzenbeanspruchung in Platten-Strukturen unter Zug-, Biege-, kombinierter Zug-Biege- und zweiaxialer Zugbelastung 2014 46. Tagung des DVM-Arbeitskreises Bruchvorgänge 46. Tagung des DVM-Arbeitskreises Bruchvorgänge Kassel, Germany 2014-02-11 2014-02-12 2016-02-20 OPUS4-30175 Beitrag zu einem Tagungsband Komann, Steffen; Kiyak, Yusuf; Wille, Frank; Zerbst, Uwe; Weber, Mike; Klingbeil, Dietmar Assessment of ductile cast iron fracture mechanics analysis within licensing of German transport packages In the design approval of transport packages for radioactive materials, the mechanical and thermal safety assessment is carried out in Germany by competent authority BAM. In recent years BAM was involved in several licensing procedures of new spent fuel and HLW package designs, where the cask body is of Ductile Cast Iron (DCI). According to IAEA regulations package designs have to fulfill requirements for specific conditions of transport. Type B(U) packages must withstand the defined accident conditions of transport. The temperature range from -40°C up to the operational temperature has to be considered. For the cask material DCI, it is necessary to determine safety against brittle fracture. The German guideline BAM-GGR 007 defines requirements for fracture mechanics of packagings made of DCI. Due to complex cask body structure and the dynamic loading a fracture mechanical assessment by analytical approaches is not always possible. Experience of recent design approval procedures show that the application of numerical calculations are applicable to determine the stresses and stress intensity factors in the cask body. At the first step a numerical analysis has to be done to identify the loading state at the whole cask body. Secondly an analysis of a detail of the cask body is made considering the displacement boundary conditions of the global model. An artificial flaw is considered in this detailed model to calculate the fracture mechanical loading state. The finite element mesh was strongly refined in the area of the flaw. The size of the artificial flaw is based on the ultrasonic inspection acceptance criteria applied for cask body manufacture. The applicant (GNS) developed additional analysis tools for calculation of stress intensity factor and/or J-Integral. The assessment approach by BAM led to the decision to develop own tools to the possibility for independent proof of the results. The paper describes the authority assessment approach for DCI fracture mechanics analysis. The validation procedure incl. the development of own tools is explained. BAM developed a postprocessor to determine the fracture mechanical loads. A horizontal 1 m puncture bar drop test is used to give a detailed description of the assessment procedure. Omnipress Institute of Nuclear Materials Management (INMM) 2013 PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials (Proceedings) PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials San Francisco, CA, USA 18.08.2013 23.08.2013 1 10 2016-02-20 OPUS4-29458 Beitrag zu einem Tagungsband Zerbst, Uwe; Klinger, Christian Anmerkungen zur Auslegung und zum sicheren Betrieb von Radsatzwellen aus der Sicht von Betriebsfestigkeit und Bruchmechanik Die Sicherheit von Radsatzwellen beruht gegenwärtig auf zwei Säulen: der Schwingfestigkeitsauslegung und periodischen Inspektionen. Ausgehend von einem Schadensfall, der gebrochenen ICE 3-Welle von Köln, 2008, sollen ausgewählte Aspekte beider Säulen diskutiert und Vorschläge zur weiteren Verbesserung gemacht werden. Diese betreffen u.a. Fragen einer Betriebszeitbegrenzung, Veränderungen der Schwingfestigkeit während des Betriebs infolge von Korrosion und Steinschlag, den Einfluss von Korrosion auf Schwingrissinitiierung und -fortschritt, den potentiellen Einfluss nichtmetallischer Einschlüsse auf die Schwingfestigkeit, die Möglichkeiten sie im Rahmen der Qualitätssicherung zu detektieren sowie Fragen der Bruchmechanik und der Zuverlässigkeit zerstörungsfreier Schwingriss-Prüfverfahren im Rahmen eines Konzepts regelmäßiger Inspektionen. Deutscher Verband für Materialforschung und -prüfung e.V. (DVM) 2013 40. Tagung des DVM-Arbeitskreises Betriebsfestigkeit - Die Betriebsfestigkeit als eine Schlüsselfunktion für die Mobilität der Zukunft 140 40. Tagung des DVM-Arbeitskreises Betriebsfestigkeit Herzogenaurach, Germany 09.10.2013 10.10.2013 69 80 2016-02-20 OPUS4-55240 Vortrag Blasón Gonzalez, Sergio; Chaudry, M.; Elorriaga, A.; Madia, Mauro; Zerbst, Uwe; Llavori, I.; Hilgenberg, Kai Design methodology of vessel produced by L PBF stainless steel using representative specimens This work presents the preliminary results of an ongoing project with a double objective: on the one hand, the characterisation of the mechanical properties against fatigue damage of an additively manufactured 316 stainless steel produced by laser powder bed-based (L-PBF) technology; on the other hand, the implementation of numerical simulation techniques able to predict the mechanical behaviour of the material in order to optimise and reduce the design costs of vessels used in the chemical sector. The current state of the work developed in this research framework allows showing the first batch of experimental results of crack propagation rate (FCGR) and high cycle fatigue (HCF) tests. The geometry of the vessels studied presents three clearly differentiated regions, either in terms of thickness (11-15 mm) or concerning the inclination of the walls to the direction of manufacturing (0º - 45º). The experimental campaign carried out so far allows identifying the differences in behaviour when comparing different extraction locations around the vessel. This is due to the variations in thermal cycles that the deposited material undergoes during the manufacturing process. Therefore, this causes variations in the microstructure which lead to changes in the response of the material. In this work, these differences are analysed qualitatively and quantitatively from the results of FCGR and HCF, thus allowing to locate the regions with the highest risk in terms of structural integrity against fatigue. This preliminary phase together with the numerical simulation of the additive manufacturing process are key to achieving a reliable description and modelling of the material. The latter will make it possible to address the priority aim of this project, involving the manufacture of independent samples whose properties are representative of the original material extracted from the reference vessels. It is, therefore, a comprehensive methodology for the design of additively manufactured components based on the localised fatigue mechanical properties of representative specimens. 2022 ECF23, European Conference on Fracture 2022 Funchal, Portugal 27.06.2022 01.07.2022 2022-07-12 OPUS4-55215 Zeitschriftenartikel Schönherr, J. A.; Duarte, Larissa; Madia, Mauro; Zerbst, Uwe; Geilen, M. B.; Klein, M.; Oechsner, M. Robust determination of fatigue crack propagation thresholds from crack growth data The robust determination of the threshold against fatigue crack propagation DKth is of paramount importance in fracture mechanics based fatigue assessment procedures. The standards ASTM E647 and ISO 12108 introduce operational definitions of DKth based on the crack propagation rate da/dN and suggest linear fits of logarithmic DK- da/dN test data to calculate DKth. Since these fits typically suffer from a poor representation of the actual curvature of the crack propagation curve, a method for evaluating DKth using a nonlinear function is proposed. It is shown that the proposed method reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density. Basel MDPI 2022 Materials 15 14 1 21 urn:nbn:de:kobv:b43-552153 10.3390/ma15144737 https://creativecommons.org/licenses/by/4.0/deed.de 2022-07-11 OPUS4-56152 Beitrag zu einem Tagungsband Baer, Wolfram; Breidung, Marc; Wossidlo, Peter; Wahl, Ken; Gerwien, Peter; Zerbst, Uwe; Madia, Mauro; Küppers, M. Zimmermann, Martina Gezielte Werkstoffprüfung zur fail-safe-Bauteilauslegung am Beispiel eines Achsschenkels Bei der Auslegung von Achsschenkeln für Nutzfahrzeuge wird für den Überlastfall ein fail-safe-Kriterium (kontrolliertes Versagen) als Basisphilosophie angesetzt. Gefordert wird, dass sich der Achsschenkel auch unter Akzeptanz begrenzten Risswachstums hinreichend elastisch-plastisch verformen kann, ohne dass es zum Bruch kommt. Der Fahrer soll anschließend anhand der bleibenden Verformungen bemerken können, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Eine Voraussetzung für dieses Bauteilverhalten ist eine hinreichende Bruchzähigkeit des Werkstoffs. Diese, wie auch die Rissspitzenbeanspruchung, müssen ermittelt werden, um den bruchmechanischen Sicherheitsnachweis führen zu können. Zur Ermittlung der mechanisch-technologischen und bruchmechanischen Werkstoffeigenschaften wurde ein Prüfkonzept entwickelt, bei dem die Proben an der potenziell kritischen Stelle direkt aus den geschmiedeten Achsschenkeln entnommen werden. Die experimentelle Werkstoffcharakterisierung bildet dann die Beanspruchungsbedingungen beim Überlastereignis ab. Im Rahmen der Produktion stehen jedoch nur Kerbschlagarbeitswerte zur Verfügung und aufwändige bruchmechanische Versuche sollen vermieden werden. Deshalb wurde eine Korrelation zur Abschätzung der vorhandenen Bruchzähigkeit aus der Kerbschlagarbeit herangezogen. Es ergibt sich eine Ergebnismatrix, die die Einflussgrößen Versagenswahrscheinlichkeit, Temperatur und Bruchzähigkeit verknüpft. Abschließend wird ein erster Vergleich der abgeschätzten mit den experimentell ermittelten Bruchzähigkeitswerten gezogen. Dieser weist aus, dass die abgeschätzten Werte geringfügig konservativ sind. Sankt Augustin DGM - Deutsche Gesellschaft für Materialkunde e.V. 2022 Werkstoffprüfung 2022 Werkstoffe und Bauteile auf dem Prüfstand, Prüftechnik – Kennwertermittlung – Schadensvermeidung 40. Vortrags- und Diskussionstagung Werkstoffprüfung 2022 Dresden, Germany 27.10.2022 28.10.2022 1 6 2022-11-02 OPUS4-54513 Zeitschriftenartikel Scacco, F.; Zerbst, Uwe; Meneghetti, G.; Madia, Mauro Comparison between PSM and IBESS approaches for the fatigue life estimation of weldments In the framework of the fatigue assessment of welded components, several methods are available in design standards such as the nominal stress, hot-spot stress, notch stress and linear elastic fracture mechanics approaches. The present paper aims at comparing two advanced local approaches for the fatigue strength assessment of different welded joints made of steel. The first one is IBESS which is based on short crack fracture mechanics. The second one is the PSM which instead involves the strain energy density approach. Both methods will be briefly presented, and the fatigue life prediction results discussed. The results obtained for the joint geometries considered in this work show advantages and drawbacks of the approaches, which are thoroughly analysed as well. Springer 2022 Welding in the World 1 23 urn:nbn:de:kobv:b43-545139 10.1007/s40194-022-01284-7 https://creativecommons.org/licenses/by/4.0/deed.de 2022-03-23 OPUS4-54490 Zeitschriftenartikel Duarte, Larissa; Madia, Mauro; Zerbst, Uwe The effect of the environmental conditions on the threshold against fatigue crack propagation The threshold against fatigue crack propagation (ΔKth) is a crucial parameter for the damage tolerance assessment of engineering components subjected to cyclic loading and it is composed by two distinct components, one intrinsic, dependent on the elastic material properties and the lattice type, and one extrinsic, related to the occurrence of crack closure effects. An important issue is that several factors can influence ΔKth and, in general, the fatigue crack propagation behavior. In this work, the influence of the experimental procedure, air humidity, stress ratio and test frequency on da/dN-ΔK data has been investigated. Results are discussed with their potential causes and consequences on the calculations of the residual lifetime. Elsevier B.V. 2022 Procedia Structutal Integrity 38 292 299 urn:nbn:de:kobv:b43-544905 10.1016/j.prostr.2022.03.030 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2022-03-21 OPUS4-54493 Zeitschriftenartikel Madia, Mauro; Zerbst, Uwe; Werner, Tiago Estimation of the Kitagawa-Takahashi diagram by cyclic R curve analysis The Kitagawa-Takahashi (KT) diagram is a proven concept for describing the fatigue limit in presence of a defect or crack. It can be determined empirically with great experimental effort. It can also be estimated by means of the El Haddad relationship if the endurance limit and the long fatigue crack propagation threshold are available in reasonable accuracy. A third option is the determination using the cyclic R-curve, which describes the dependency of the fatigue crack propagation threshold on the crack growth at the short crack propagation stage. This can be experimentally determined using a closure-free initial pre-crack. It can then be applied to the determination of crack arrest for a given applied load and a given defect or crack size. Compared to the other two methods mentioned above, this option has considerable advantages: It can be applied to any component and any stress ratio. It allows the treatment of multiple cracks and provides estimations of the S-N curve in the finite life regime as well as at the endurance limit. Compared to the empirical determination of the KT diagram, the experimental effort is significantly lower and compared to the El Haddad approach it avoids problems such as the use of non-conservative long fatigue crack propagation thresholds (when the conventional load reduction method is applied to materials prone to corrosion) and the mathematical predetermination of the curve shape. The work introduces the method and provides a critical discussion as well as quantitative comparison between the different methods. Elsevier B.V. 2022 Procedia Structural Integrity 38 FATIGUE DESIGN 2021 Online meeting 17.11.2021 18.11.2021 309 316 urn:nbn:de:kobv:b43-544931 10.1016/j.prostr.2022.03.032 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2022-03-21 OPUS4-54495 Zeitschriftenartikel Werner, Tiago; Madia, Mauro; Zerbst, Uwe Comparison of the fatigue behavior of wrought and additively manufactured AISI 316L Additive manufacturing (AM) is becoming increasingly important in engineering applications due to the possibility of producing components with a high geometrical complexity allowing for optimized forms with respect to the in-service functionality. Despite the promising potential, AM components are still far from being used in safety-relevant applications, mainly due to a lack of understanding of the feedstock-process-properties-performance relationship. This work aims at providing a full characterization of the fatigue behavior of the additively manufactured AISI 316L austenitic stainless steel and a direct comparison with the fatigue performance of the wrought steel. To this purpose, a set of specimens has been produced by laser powder bed fusion (L-PBF) and subsequently heat treated at 900 °C for 1 hour for complete stress relief, whereas a second set of specimens has been machined out of hot-rolled plates. Low cycle fatigue (LCF) and high cycle fatigue (HCF) tests have been conducted for characterizing the fatigue behavior. The L-PBF material had a higher fatigue limit and better finite life performance compared to wrought material. Both, LCF and HCF-testing revealed an extensive cyclic softening. Elsevier B.V. 2022 Procedia Structural Integrity 38 FATIGUE DESIGN 2021 Online meeting 17.11.2021 18.11.2021 554 563 urn:nbn:de:kobv:b43-544952 10.1016/j.prostr.2022.03.056 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2022-03-21 OPUS4-54403 Beitrag zu einem Tagungsband Zhu, Jiangchao; Schurig, M.; Schlums, H.; Madia, Mauro; Zerbst, Uwe Bruchmechanische Bewertung der Integrität einer Turbinenscheibe bei Überdrehzahl Turbinenscheiben sind thermisch und mechanisch hochbeanspruchte, sicherheitsrelevante Komponenten in Gasturbinen. Ihre Integrität wird in Bauteiltests unter Überdrehzahlbedingungen nachgewiesen. Kontext des Aufsatzes ist die Erarbeitung einer zusätzlichen Bewertungsebene auf der Grundlage von Versuchen unter monotoner Beanspruchung, die die Beanspruchung im Bauteil realistisch wiedergeben soll. Betrachtet wird ein halbelliptischer Riss, der bei der weiteren Ausbreitung als Umfangsriss wächst (rim peeling). Die Simulation dieser Stelle im Bauteil schließt die mechanische und thermische Beanspruchung sowie sie Dehnungsbehinderung ein. Letztere wird anhand zweier Parameter, der Spannungsmehrachsigkeit ℎ und des (allerdings modifizierten) Constraint-Parameters nach Newman, der die Spannungen über den plastisch verformten Bereich mittelt, bestimmt. Erwartungsgemäß zeigt sich, dass die höchste Dehnungsbehinderung weder an den Oberflächenpunkten, noch an den tiefsten Punkten, sondern an einer Stelle zwischen beiden auf der Rissfront auftritt. Als Versuchsgeometrie für die monotonen Tests soll eine Kreuzprobe mit wanddurchdringenden Rissen ausgehend von einer Innenbohrung dienen. Durch geeignete Wahl der Risstiefe sowie der in beiden Richtungen angreifenden Kräfte gelingt es, bauteiladäquate Zustände zu erzeugen. Deutscher Verband für Materialforschung und -prüfung e.V. 2022 Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit Online meeting 22.02.2022 23.02.2022 13 22 2022-02-28 OPUS4-54406 Beitrag zu einem Tagungsband Baer, Wolfram; Breidung, Marc; Kiyak, Yusuf; Zerbst, Uwe; Madia, Mauro; Küppers, M. Aspekte der analytischen bruchmechanischen Bauteilbewertung Am Beispiel eines abgesetzten zylindrischen Bauteils (Achsschenkel) werden Probleme der analytischen bruchmechanischen Bauteilbewertung diskutiert. Als Basis-philosophie wird ein Fail Safe-Kriterium (kontrolliertes Versagen) angesetzt. Die Forderung ist, dass sich der Achsschenkel, bevor er bricht, in einem Ausmaß plastisch verformen kann, bei dem der Fahrer bemerkt, dass mit seinem Fahrzeug etwas nicht in Ordnung ist. Um das zu gewährleisten, muss der Werkstoff einen bestimmten Riss-widerstand aufweisen. Dazu werden im hier vorgestellten ersten Teil des Projektes mittels FEM Rissspitzenbeanspruchungen in Abhängigkeit von der Auslenkung des Zylinders und angenommener Rissgrößen ermittelt. Diese finden als Zielgrößen in der weiteren Analyse Anwendung. Da eine einfach umzusetzende Lösung angestrebt wird, werden zusätzlich analytische Rechnungen an Ersatzgeometrien (halbunendliche Platte und Vollzylinder), aber mit den realen Spannungen am Bauteil durchgeführt. Es zeigt sich, dass die Ergebnisse wegen des Steifigkeitsunterschieds zwischen Bauteil und Ersatzgeometrie unvertretbar konservativ sind. Alternativ wird ein hybrides Konzept vorgestellt, für das die Modellparameter mittels FEM bestimmt werden. Es liefert sehr genaue Ergebnisse. Im Rahmen der analytischen Rechenvorschrift können die Lösungen auf andere Werkstoffe übertragen werden, ohne dass zusätzliche FEM-Analysen notwendig sind. Berlin DVM 2022 Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen 254 54. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit Online meeting 22.02.2022 23.02.2022 1 11 10.48447/Br-2022-BB 2022-03-02 OPUS4-53079 Zeitschriftenartikel Schork, B.; Zerbst, Uwe; Kiyak, Yusuf; Kaffenberger, M.; Madia, Mauro; Oechsner, M. Effect of the parameters of weld toe geometry on the FAT class as obtained by means of fracture mechanics-based simulations The fracture mechanics-based IBESS approach is applied to the determination of FAT classes of butt welds with crack Initiation along the weld toe. The aim is an investigation of the effect of the geometrical parameters toe radius, flank angle, reinforcement and secondary notches such as roughness or undercuts. The influence of these parameters is discussed both individually and in combination; however, excluding statistical distributions of them and the material data. The results, when compared with conventional FAT classes for butt welds, are encouraging with respect to a potential contribution of IBESS to the discussion of more advanced quality criteria for welds. To that purpose, demands for further research are proposed. Springer 2020 Welding in the World 64 925 936 10.1007/s40194-020-00874-7 2021-08-11 OPUS4-53082 Zeitschriftenartikel Bergant, M.; Werner, Tiago; Madia, Mauro; Yawny, A.; Zerbst, Uwe Short crack propagation analysis and fatigue strength assessment of additively manufactured materials: An application to AISI 316L This paper presents the application of short crack propagation models based on the cyclic R-curve for assessing the fatigue strength of additively manufactured (AM) materials containing fabrication defects. Chapetti's and IBESS models were implemented in combination with Murakami's √area parameter, considering recently published data on laser powder bed fusion processed AISI 316L stainless steels. Estimated S-N curves and Kitagawa-Takahashi diagrams predict fairly well the experimental data, especially the origin of the failure from internal or surface defects. These results provide an indication that the methods based on the cyclic R-curve constitute suitable tools for fatigue behavior assessment of AM materials. Elsevier Ltd. 2021 International Journal of Fatigue 151 10.1016/j.ijfatigue.2021.106396 2021-08-11 OPUS4-53525 Zeitschriftenartikel Madia, Mauro; Vojtek, T.; Duarte, Larissa; Zerbst, Uwe; Pokorný, P.; Jambor, M.; Hutař, P. Determination of fatigue crack propagation thresholds for steel in presence of environmental effects The experimental determination of the resistance to fatigue crack propagation in steel, particularly in the socalled near-threshold regime, is a crucial issue for safety-relevant components which are designed to operate for a large number of loading cycles before undergoing periodic inspections. This work summarizes the most relevant results of extensive experimental campaigns conducted at BAM and IPM over the last years, which have been devoted to the determination of fatigue crack propagation characteristics on medium and high strength steels. The influence of environment, oxide-induced crack closure and test methodologies in the near-threshold regime are discussed. Elsevier Ltd. 2021 International Journal of Fatigue 153 1 10.1016/j.ijfatigue.2021.106449 2021-10-14 OPUS4-52704 Beitrag zu einem Tagungsband Duarte, Larissa; Zerbst, Uwe; Madia, Mauro Vergleichende Untersuchungen zum intrinsischen Schwellenwert der da/dN-ΔK-Kurve Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung, Δ𝐾𝑡ℎ, und dem sich anschließenden Schwellenwertbereich der 𝑑𝑎𝑑𝑁⁄−Δ𝐾-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie" Analyse der Restlebensdauer von entscheidender Bedeutung ist. Berlin Deutscher Verband für Materialforschung und -prüfung e.V. (DVM) 2021 Bruchmechanische Werkstoff- und Bauteilbewertung: Beanspruchungsanalyse, Prüfmethoden und Anwendungen 53. Tagung des DVM-Arbeitskreises Bruchmechanik und Bauteilsicherheit Online meeting 18.02.2021 19.02.2021 211 220 2021-05-31 OPUS4-52788 Beitrag zu einem Tagungsband Duarte, Larissa; Zerbst, Uwe; Madia, Mauro Der Schwellenwert der da/dN-∆K-Kurve als Auslegungskriterium für die Bauteilbewertung Für die Bestimmung der Restlebensdauer zyklisch beanspruchter Bauteile kommt dem Schwellenwert für Ermüdungsrissausbreitung ∆Kth und dem sich anschließenden Schwellenwertbereich der da/dN-∆K-Kurve große Bedeutung zu. Dem stehen Unsicherheiten bei der Bestimmung und Analyse gegenüber. Der Aufsatz befasst sich mit der Ermittlung des sogenannten intrinsischen Schwellenwerts, der als robuster Eingangsparameter für eine „rissschließfreie" Analyse der Restlebensdauer von entscheidender Bedeutung ist. 2020 Werkstoffe und Bauteile auf dem Prüfstand. Prüftechnik - Kennwertermittlung - Schadensvermeidung Tagung Werkstoffprüfung 2020 Online meeting 03.12.2020 04.12.2020 1 8 10.48447/WP-2020-025 2021-06-10 OPUS4-52854 Buchkapitel Zerbst, Uwe; Madia, Mauro Yadroitsev, I.; Yadroitsava, I.; Du Plessies, A.; McDonald, E. Structural integrity II: fatigue properties If a component is cyclically loaded, its load carrying capacity is considerably lower than in the monotonic loading case. This general observation applies in particular to L-PBF parts. The causes of this are mainly material defects such as pores and unwelded regions (Chapter 8) and a pronounced surface roughness in the as-built condition (Chapter 9). In addition, effects due to the anisotropy of the microstructure (Chapter 6) and a complex residual stress pattern (Chapter 7) play an important role. A consequence is that common strategies of fatigue assessment cannot be transferred to L-PBF applications without modifications. Due to the inhomogeneity of the material, the determination of representative material properties and the transfer to the component is a problem, and this is also the case with regard to the consideration of defects, surface roughness and residual stresses. The chapter gives a brief introduction to these problem areas. 1 Amsterdam Elsevier Inc. 2021 Fundamentals of laser powder bed fusion of metals 978-0-12-824090-8 377 394 10.1016/B978-0-12-824090-8.00015-9 2021-06-24 OPUS4-52582 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Bruno, Giovanni; Hilgenberg, Kai Towards a Methodology for Component Design of Metallic AM Parts Subjected to Cyclic Loading The safe fatigue design of metallic components fabricated by additive manufacturing (AM) is still a largely unsolved problem. This is primarily due to (a) a significant inhomogeneity of the material properties across the component; (b) defects such as porosity and lack of fusion as well as pronounced surface roughness of the asuilt components; and (c) residual stresses, which are very often present in the as-built parts and need to be removed by post-fabrication treatments. Such morphological and microstructural features are very different than in conventionally manufactured parts and play a much bigger role in determining the fatigue life. The above problems require specific solutions with respect to the identification of the critical (failure) sites in AM fabricated components. Moreover, the generation of representative test specimens characterized by similar temperature cycles needs to be guaranteed if one wants to reproducibly identify the critical sites and establish fatigue assessment methods taking into account the effect of defects on crack initiation and early propagation. The latter requires fracture mechanics-based approaches which, unlike common methodologies, cover the specific characteristics of so-called short fatigue cracks. This paper provides a discussion of all these aspects with special focus on components manufactured by laser powder bed fusion (L-PBF). It shows how to adapt existing solutions, identifies fields where there are still gaps, and discusses proposals for potential improvement of the damage tolerance design of L-PBF components Basel MDPI 2021 Metals 11 5 709 urn:nbn:de:kobv:b43-525822 10.3390/met11050709 https://creativecommons.org/licenses/by/4.0/deed.de 2021-05-05 OPUS4-55903 Beitrag zu einem Tagungsband Zhu, Jiangchao; Madia, Mauro; Schurig, M.; Schlums, H.; Zerbst, Uwe Fracture mechanics-based structural integrity assessment of aeroengine turbine disks under overspeed conditions Aero-engine turbine disks are safety-relevant components which are operated under high thermal and mechanical stress conditions. The actual part qualification and certification procedures make use of spin-tests conducted on productionsimilar disks. While these tests provide, on the one hand, a reliable definition of the critical conditions for real components, on the other hand they represent a relevant cost item for engine manufacturers. The aim of this work is to present part of a fracture mechanics-based procedure under development which aims at replacing the tests on production-similar disks with lab tests on fracture mechanics specimens. In particular, the rimpeeling failure mode is considered as case study. A semi-circular surface crack is modelled at the most stressed region at the diaphragm of a turbine disk, with the crack plane perpendicular to the radial direction. The crack is therefore subjected to a biaxial stress state and grows under increasing rotational speed until it triggers the rim-peeling failure. The finite element simulation of the cracked disk considers the real thermal and mechanical loading conditions. In order to design a lab representative specimen, beside the crack driving force, expressed in terms of � -integral, also the constraint to plastic deformation e.g., stress triaxiality, at the crack-tip must be similar for the same crack in the specimen and in the disk. This has been achieved and as expected, both the highest � -integral and constraint factor are calculated at the same location along the crack front for both disk and specimen. The results of the structural integrity assessment in the form of a Failure Assessment Diagram (FAD) show good agreement between designed specimen and disk both in terms of expected failure mode and value of the critical speed. Probabilistic aspects are also considered in the calculations. ASME 2022 Proceedings of ASME Turbo Expo 2022 ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition (GT2022) Rotterdam, The Netherlands 13.06.2022 17.06.2022 1 7 2022-10-06 OPUS4-55544 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Kiyak, Yusuf; Breidung, Marc; Baer, Wolfram; Küppers, M. Madia, Mauro Stiffness/constraint effects in analytical flaw assessment - A technical note Using the case study of a fail-safe design criterion for a steering knuckle of a commercial vehicle, the effect of stiffness/constraint on the crack driving force in the component is discussed. The problem arises when assessment procedures such as R6, BS 7910 or SINTAP/FITNET are applied in conjunction with substitute geometries for determining the model parameters K-factor and limit load (or a substitute for the latter), as it is common practice. In the example, the conservatism was so pronounced that this procedure was in fact unusable. A way out could be the finite element-based determination of the model parameters and their use in the analytical framework. This procedure is useful and effective if the finite element-based calculations are used in parameter sensitivity analyses. Kidlington Elsevier Science 2022 Engineering Fracture Mechanics 273 1 15 10.1016/j.engfracmech.2022.108728 2022-08-23 OPUS4-56004 Monographie Zerbst, Uwe; Madia, Mauro Bruchmechanische Bauteilbewertung Die sichere Auslegung von Bauteilen kommt an der Anwendung bruchmechanischer Methoden heute nicht mehr vorbei. Das vorliegende Buch bietet eine Einführung in diese Methoden mit besonderen Schwerpunkten auf dem aktuellen Stand der bruchmechanischen Kennwertermittlung und den Methoden der analytischen bruchmechanischen Bauteilbewertung. Es beschreibt die Mechanismen von Risswachstum und Bruch, die grundlegenden Konzepte der Bruchmechanik, die analytische Ermittlung der Rissspitzenbelastung in Bauteilen sowie die Anwendung der Bruchmechanik in unterschiedlichen Kontexten. Der Schwerpunkt liegt dabei auf der praktischen Anwendung u. a. anhand von Demonstrationsbeispielen, die im Detail nachvollzogen werden können. Heidelberg Springer 2022 978-3-658-36150-1 C1 372 10.1007/978-3-658-36151-8 2022-10-19 OPUS4-55403 Zeitschriftenartikel Duarte, Larissa; Madia, Mauro; Zerbst, Uwe; Schönherr, J. A.; Geilen, M. B.; Klein, M.; Oechsner, M. Recent developments in the determination of fatigue crack propagation thresholds The impact of crack closure and environmental effects on the experimental determination of the fatigue crack propagation threshold is a major problem for the assessment of cyclically loaded components, especially at low stress ratios 𝑅. In this work, the influence of the experimental procedure and air humidity on d𝑎∕d𝑁 − 𝛥𝐾 data at different 𝑅 is discussed. Unlike the results at 𝑅 = −1, the threshold values obtained at 𝑅 ≈ 0.8, i.e. under negligible crack closure levels, show a very small scatter band regardless of the variation of the test parameters and environmental conditions. Elsevier Ltd. 2022 International Journal of Fatigue 164 1 15 10.1016/j.ijfatigue.2022.107131 2022-08-03 OPUS4-36157 Beitrag zu einem Tagungsband Zerbst, Uwe; Madia, Mauro; Schork, Benjamin Fracture mechanics based determination of the fatigue strength of weldments A fracture mechanics model which shall be applied to the fatigue strength determination of weldments has to focus on various aspects such as: (a) the description of mechanical and physical short fatigue crack extension which is characterised by yielding conditions which do not permit the application of the common ΔK concept and by the gradual build-up of the crack closure effect, (b) a consistent methodology for determining the initial crack size, (c) based on this, the determination of a fatigue limit, (d) the treatment of multiple crack propagation at load levels above this limit, (e) the variation of the local geometry along the weld toe, and (f) statistical effects.The paper gives alimited overview of the work the authors did in this field during the last years within the German project cluster IBESS. A model is presented and briefly discussed which covers the questions above. Amsterdam, Netherlands Elsevier B.V. 2016 Procedia Structural Integrity 2016/1 XV Portugese Conference on Fracture Lissabon, Portugal 10.02.2016 12.02.2016 10 17 urn:nbn:de:kobv:b43-361571 doi:10.1016/j.prostr.2016.02.003 http://creativecommons.org/licenses/by-nc-nd/3.0/de/deed.de 2016-05-24 OPUS4-30323 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Eufinger, J.; Bruder, T. Bruchmechanisches Modell zur Ermittlung der Schwingfestigkeit von geschweißten und nichtgeschweißten Proben Ermüdungsrisse gehen in technischen Materialien in der Regel von Werkstoffdefekten auf oder nahe der Oberfläche aus. Bei Schweißverbindungen können Schweißnahtdefekte, z. B. oberflächennahe Schlackeneinschlüsse die Risseinleitungsphase erheblich verkürzen, so dass der Hauptteil der Lebensdauer auf die Phase der Kurzriss- und zu geringerem Anteil auf die Langrissausbreitung entfällt. Bei nichtgeschweißten Bauteilen aus technischen Werkstoffen starten Ermüdungsrisse häufig an Einschlüssen, oberflächennahen Poren oder anderen Ungänzen. Einerseits ermöglicht dies prinzipiell die Anwendung bruchmechanischer Methoden zur Ermittlung der Schwingfestigkeit, andererseits müssen die Methoden in der Lage sein, spezielle Aspekte des Kurzrisswachstums wie den graduellen Aufbau des Rissschließeffekts und die lokale Rissspitzenplastizität zu erfassen. Im Beitrag werden ein geeignetes analytisches Modell sowie erste Validierungen an Proben aus verschiedenen Aluminiumlegierungen vorgestellt. Der abschließende Teil des Beitrags geht auf Besonderheiten von Schweißverbindungen (Schweißnahtdefekte, Eigenspannungen etc.) im Kontext des vorgestellten Modells ein. Eine Erweiterung des Modells für Schweißverbindungen aus Stahl wird im Rahmen eines kürzlich gestarteten DFG-AiF-Clusterprojekts erfolgen. München Hanser Bundesanstalt für Materialforschung und -prüfung 2013 Materials Testing 55 7-8 511 519 10.3139/120.110465 2016-02-20 OPUS4-31321 Beitrag zu einem Tagungsband Zerbst, Uwe Baumgartner, J.; Melz, T. Assessment of welded joints by fracture mechanics IBESS - the development of a procedure The idea to determine the fatigue strength of weldments by means fracture mechanics was originally based on the empirical observation that the major portion of the fatigue life in weldments is frequently spent in crack propagation. The present paper gives a brief overview on the basic principles of fracture mechanics-based determination of fatigue strength and on special features which have to be considered for weldments. Based on this information, the ongoing research project IBESS is introduced and briefly reviewed. Fraunhofer Verlag 2014 SoSDiD - 4th Symposium on structural durability in Darmstadt (Proceedings) SoSDiD - 4th Symposium on structural durability in Darmstadt Darmstadt, Germany 2014-05-14 2014-05-15 49 66 2016-02-20 OPUS4-31355 Zeitschriftenartikel Zerbst, Uwe; Klinger, Christian Anmerkungen zur Auslegung und zum sicheren Betrieb von Radsatzwellen aus der Sicht von Betriebsfestigkeit und Bruchmechanik Die Sicherheit von Radsatzwellen beruht gegenwärtig auf zwei Säulen: der Schwingfestigkeitsauslegung und periodischen Inspektionen. Ausgehend von einem Schadensfall, der gebrochenen ICE 3-Welle von Köln, 2008, werden ausgewählte Aspekte dieser beiden Säulen diskutiert und Vorschläge zur weiteren Verbesserung gemacht. Diese betreffen u. a. Fragen einer Betriebszeitbegrenzung, Veränderungen der Schwingfestigkeit während des Betriebs infolge von Korrosion und Steinschlag, den Einfluss von Korrosion auf Schwingrissinitiierung und -fortschritt, den potenziellen Einfluss nichtmetallischer Einschlüsse auf die Schwingfestigkeit, die Möglichkeiten, sie im Rahmen der Qualitätssicherung zu detektieren, sowie Fragen der Bruchmechanik und der Zuverlässigkeit zerstörungsfreier Schwingriss-Prüfverfahren im Rahmen eines Konzepts regelmäßiger Inspektionen. München Hanser Bundesanstalt für Materialforschung und -prüfung 2014 Materials testing 56 7-8 528 534 10.3139/120.110593 2016-02-20 OPUS4-30452 Zeitschriftenartikel Zerbst, Uwe; Madia, Mauro; Beier, H.T. A model for fracture mechanics based prediction of the fatigue strength: Further validation and limitations Recently two of the authors of the present paper proposed a model for a fracture mechanics based prediction of the S-N characteristics of metallic components with large microstructural defects and supported this by a validation exercise on tensile plates made of an aluminium alloy AL5380 H321. Here the authors extend the study using a number of further data sets from the literature for which data were available at different R ratios. These data include two aluminium alloys, Al 2024-T3 and Al 7075-T6, and a ductile cast iron, EN-GJS- 400-18-LT. Despite of necessary assumptions for the compensation of partially missing input information the results were fairly reasonable with the exception of one data set. The authors identify high applied stress levels in combination with potential multiple crack initiation as the probable root of the problem and propose a scheme how the model can be extended for taking into account crack initiation. Kidlington Elsevier Science 2014 Engineering fracture mechanics 1 17 10.1016/j.engfracmech.2013.12.005 2016-02-20 OPUS4-31429 Zeitschriftenartikel Madia, Mauro; Arafah, D.; Zerbst, Uwe Reference load solutions for plates with semi-elliptical surface cracks subjected to biaxial tensile loading The yield or limit load is a key parameter with respect to the accuracy of flaw assessment based on R6 type procedures such as the R6 routine, the SINTAP and FITNET method, the standard BS 7910 and others. In a number of previous papers two of the present authors proposed the use of a reference load instead of the common limit load, which not only provided more exact fracture mechanics predictions, but showed also a wider and more general application range than the conventional parameter. Here the method has been extended to biaxial tensile loading and it has been successfully validated by a thorough comparison with finite element results and alternative solutions available in the literature. Barking Applied Science Publ. Ltd. 2014 International journal of pressure vessels and piping 119 19 28 10.1016/j.ijpvp.2014.02.004 2016-02-20