TY - CONF A1 - Salge, T. A1 - Terborg, R. A1 - Ball, A. D. A1 - Broad, G.R. A1 - Kearsley, A.T. A1 - Jones, C.G. A1 - Smith, C. A1 - Rades, Steffi A1 - Hodoroaba, Vasile-Dan ED - Hozak, P. T1 - Advanced SEM/EDS analysis using an annular silicon drift detector (SDD): Applications in nano, life, earth and planetary sciences below micrometer scale N2 - Analysis of fine-scale structures requires low accelerating voltages. Consequently, only low to intermediate energy X-ray lines with many peak overlaps can be evaluated which requires deconvolution. Examination of nano-scale structures also requires low probe currents which would give low X-ray count rates with traditional EDX detectors. The additional time required to acquire sufficient data for deconvolution risks altering the specimen as a result of beam-sample interaction or sample contamination. The BRUKER XFIash 5060F SDD has allowed us to overcome these limitations and offers additional benefits as we demonstrate here. T2 - IMC 2014 - 18th International microscopy congress CY - Prague, Czech Republic DA - 07.09.2014 PY - 2014 SN - 978-80-260-6720-7 SP - IT-5-P-1842, 1-2 AN - OPUS4-31944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rockenhäuser, Christian A1 - von Hartrott, P. A1 - Metzger, M. A1 - Schriever, Sina A1 - Augenstein, E. A1 - Karlin, J. A1 - Piesker, Benjamin A1 - Schweizer, Ch. A1 - Skrotzki, Birgit T1 - Lebensdauerberechnung von Aluminium-Radialverdichterrädern unter Berücksichtigung der Werkstoffalterung N2 - In this project, a procedure was developed to improve the lifetime assessment precision of exhaust turbo charger radial compressor wheels made from the age hardenable aluminum alloy EN AW-2618A. This comprises particularly the consideration of material aging, which has to be anticipated during operation of such components under relevant service conditions (temperature, time, stress). First of all, a solid experimental database was established for the investigated material. This includes a mechanical as well as a microstructural characterization of the as-received state (T61) and after aging up to 25,000 h at relevant service temperatures (160 °C, 180 °C, 190 °C). The microstructural investigations focused on the development of the radii of the cylindrical hardening phase, which coarsens during aging. The relation between aging temperature, time and mechanical load (if applicable) was established for the first time to this extent. An interrelationship to describe the coarsening was established. The effect of aging on hardness, strength, creep behavior and fatigue lifetime (LCF, TMF) was studied and a correlation to the microstructure was established. The results of the creep tests were used to calibrate a modified hyperbolic sine creep model. A time and temperature dependent deformation model according to Chaboche, which describes the relevant phenomena of high temperature deformation and cyclic plasticity, was extended. It now considers material aging by describing the strength not only as a function of temperature but also as a function of aging, i.e. of the mean radius of the precipitates. A similar procedure was applied to extend the model in order to assess the fatigue lifetime. The calculated lifetimes of LCF and TMF tests completed during this project match well with the experimental results. Only one LCF test with a hold time of 900 s in tension deviates clearly from the mean value and shows the limits of the time independent damage model. Tests with shorter hold times of 60 s are within the scatter band, likewise the different aging conditions. A damage accumulation model additionally describing the progressive aging during lifetime was developed and implemented. Besides considering aging in the deformation and lifetime assessment, it is also possible to judge complex loading cycles in a postprocessing by rain flow classification of typical complex loading cycles. The methodology and the models were implemented into the Finite-Element software Abaqus and Ansys and are available for numerical assessment of components. N2 - In diesem Forschungsvorhaben wurde ein Verfahren entwickelt, um die Genauigkeit der Lebensdauerbewertung für Abgasturbolader (ATL)-Verdichterräder aus der ausscheidungs-härtbaren Aluminiumlegierung EN AW-2618A zu verbessern. Dies umfasst insbesondere die Berücksichtigung der Werkstoffalterung, mit der beim Einsatz dieser Bauteile unter entsprechender Betriebsbeanspruchung (Temperatur, Zeit, Spannung) gerechnet werden muss. Zunächst wurde eine solide experimentelle Datenbasis für den untersuchten Werkstoff geschaffen. Dies umfasste sowohl eine mechanische als auch eine mikrostrukturelle Charakterisierung des Ausgangszustands (T61) sowie von ausgelagerten Zuständen bis zu 25.000 h bei betriebsrelevanten Temperaturen (160 °C, 180 °C, 190 °C). Bei den Untersuchungen zur Mikrostruktur wurde der Fokus auf die Entwicklung der Radien der stäbchen-förmigen aushärtenden Phase gelegt, die während der Alterung vergröbern. Der Zusammenhang zwischen Auslagerungstemperatur, -zeit und ggfs. mechanischer Belastung wurde erstmals in diesem Umfang quantifiziert und entsprechende Gesetzmäßigkeiten zur Beschreibung der Vergröberung ermittelt. Vergleichend dazu wurde der Einfluss der Alterung auf die Härte, die Festigkeit, das Kriechverhalten und die Ermüdungslebensdauer (LCF, TMF) bestimmt, so dass eine Korrelation zur Mikrostruktur vorliegt. Die Ergebnisse der Kriechversuche wurden zur Kalibrierung eines modifizierten Sinus-hyperbolicus-Kriechmodells verwendet. Ein zeit- und temperaturabhängiges Verformungsmodell nach Chaboche, welches die wesentlichen Phänomene der Hochtemperaturverformung und der Wechselplastizität beschreibt, wurde erweitert und berücksichtigt nun die Werkstoffalterung, indem die Festigkeit nicht nur als Funktion der Temperatur, sondern auch des Alterungszustands (d. h. des mittleren Radius der Ausscheidungen) dargestellt wird. Für die Erweiterung des Modells zur Bewertung der Ermüdungslebensdauer wurde analog verfahren. Die berechnete Lebensdauer der im Verlauf des Vorhabens durchgeführten LCF- und TMF-Versuche stimmt gut mit den experimentellen Ergebnissen überein. Lediglich ein LCF-Versuch mit einer Haltezeit von 900 s im Zug weicht deutlich vom Mittelwert ab und zeigt die Grenzen des zeitunabhängigen Schädigungsmodells auf. Versuche mit kürzeren Haltezeiten bis zu 60 s liegen im Streuband, ebenso die verschiedenen Alterungszustände. Eine Schädigungsakkumulation unter Berücksichtigung der fortschreitenden Alterung über der Lebensdauer wurde entwickelt und implementiert. Neben der Berücksichtigung der Alterung in der Verformungs- und Lebensdaueranalyse besteht auch die Möglichkeit, komplexe Belastungszyklen in einem Postprozessing zu bewerten, indem Rainflow-Klassierungen typischer komplexer Belastungszyklen vorgenommen werden. Die Methodik und die Modelle wurden in die Finite-Elemente-Programme Abaqus und Ansys implementiert und stehen für die rechnerische Bewertung von Bauteilen zur Verfügung. T2 - FVV Frühjahrstagung 2018 CY - Bad Neuenahr, Germany DA - 22.03.2018 KW - Aluminium KW - Centrifugal compressor wheel KW - Dark-field transmission electron microscopy (DFTEM) KW - Degradation KW - S-phase PY - 2018 SP - 97 EP - 130 AN - OPUS4-44604 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Skrotzki, Birgit A1 - Uckert, Danilo A1 - Kühn, Hans-Joachim A1 - Matzak, Kathrin A1 - Rehmer, Birgit ED - Grellmann, W. ED - Frenz, H. T1 - Ermüdungsverhalten des warmfesten austenitischen Gusseisens EN-GJSA-XNiSiCr35-5-2 bei hoher Temperatur T1 - Fatigue behavior of the heat resistant austenitic cast iron EN-GJSA-XNiSiCr35-5-2 at high temperature N2 - Das Ermüdungsverhalten des austenitischen Gusseisens EN-GJSA-XNiSiCr35-5-2 mit Kugelgraphit wurde mittels LCF- und TMF-Versuchen bei hoher Temperatur charakterisiert. Neben der Lebensdauer wurden das zyklische Ver- und Entfestigungsverhalten und das zyklische Spannungs- Dehnungs-Verhalten untersucht. Die Ergebnisse zeigen einen deutlichen Einfluss der Temperatur auf die Festigkeit und das isotherme Ermüdungsverhalten. Dies gilt für die Ermüdungslebensdauer ebenso wie für das Wechselverformungsverhalten. Das TMF-Verhalten wird von der gewählten Maximaltemperatur bestimmt. Der Einfluss der Phasenlage ist bei dem hier untersuchten Werkstoff deutlich weniger ausgeprägt als z.B. bei einem ebenfalls untersuchten ferritischen Gusseisen vom Typ SiMo. N2 - The fatigue behavior of the austenitic ductile cast iron EN-GJSA-XNiSiCr35-5-2 was characterized by LCF and TMF tests at high temperature. Beside the lifetime, the cydic hardening and softening behavior as well as the cydic stress strain behavior were studied. The results show a distinct effect of the temperature on strength and on isothermal fatigue behavior. This is true for fatigue life as well as for the cydic deformation behavior. The TMF behavior is determined by the chosen maximum temperature. The effect of the phase angle, is deariy less pronounced than e.g. in the likewise investigated ferritic ductile cast iron of type SiMo. T2 - Tagung Werkstoffprüfung 2014 - Fortschritte in der Werkstoffprüfung für Forschung und Praxis - Werkstoffeinsatz, Qualitätssicherung und Schadensanalyse CY - Berlin, Germany DA - 04.12.2014 KW - EN-GJSA-XNiSiCr35-5-2 KW - LCF KW - TMF KW - Ermüdung bei hoher Temperatur KW - Fatigue at high temperature PY - 2014 SN - 978-3-9814516-8-9 SN - 1861-8154 SP - 61 EP - 66 AN - OPUS4-32223 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kling e Silva, Lucas A1 - Pereira, Gabriela Ribeiro A1 - Jardim, Paula Mendes A1 - Sonntag, Nadja A1 - Skrotzki, Birgit T1 - CARACTERIZAÇÃO MAGNÉTICA DOS EFEITOS DE DEFORMAÇÃO EM AÇOS ESTRUTURAIS ATRAVÉS DA TÉCNICA BITTER MODIFICADA N2 - The plastic deformation results in irreversible microstructure changes in the steel, which can be considered as the initial stage of the fracture process. However, detecting, monitoring and evaluating, damage states and small defects non-destructively in advance still proves challenging. It was reported in literature the phenomenon of the spontaneous emergence of weak magnetic fields in structural steels and pipelines, which originates due to heterogeneous mechanical and / or thermal stresses. This observation is not associated with induced phase transformations by deformation and appears to be a promising tool for the prior characterization of damage in ferromagnetic steels. To provide a better understanding of the physical bases of the process, the magnetic microstructure of such materials and the change of magnetic domains after undergoing plastic deformation were studied. For this purpose, a colloidal solution with paramagnetic particles in the nanometer scale (ferrofluid) was used, through the Bitter technique, in order to, not only observe a change in size of the magnetic domains of the material, but also changes in their morphology. Ferritic steels with different carbon contents (0.08%; 0.22% and 0.45%) were studied in this work. T2 - ABM Week 2017 CY - Sao Paulo, Brazil DA - 02.10.2017 KW - Magnetic domains KW - Steels KW - Ferrofluid KW - Plastic deformation PY - 2017 DO - https://doi.org/10.5151/1516-392X-30810 SN - 2594-5327 VL - 72 IS - 1 SP - 3003 EP - 3013 PB - Blucher Preceeding CY - Brasilien AN - OPUS4-48876 LA - por AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koch, Claudia A1 - Blind, K. ED - Jakobs, K. ED - Morone, P. T1 - Testbeds for standardization in the IIoT N2 - In the paper, we discuss the role and impacts of testbeds in standardization for the industrial internet of things. Based on a multiple case study, four different approaches were identified followed in the testbeds with regard to their standardization activities. T2 - 24th EURAS Annual Standardisation Conference CY - Rom, Italy DA - 13.06.2019 KW - IIoT KW - Industrie 4.0 KW - Normen KW - Standards KW - Normung KW - Standardization KW - Agile KW - Testbed PY - 2019 SN - 978-3-95886-282-1 SP - 215 EP - 234 PB - Verlagshaus Mainz CY - Aachen AN - OPUS4-49121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, I. A1 - Moll, J. A1 - Kexel, C. A1 - Schubert, L. A1 - Tschöke, K. A1 - Prager, Jens A1 - Lugovtsova, Yevgeniya A1 - Bach, M. A1 - Vogt, T. T1 - SHM using Guided Waves – Recent Activities and Advances in Germany N2 - Issues that prevent Structural Health Monitoring (SHM) based on Guided Waves (GW) from being a part of today’s monitoring solutions in industry are not all obvious to the scientific community. To uncover and overcome these issues, scientists working on SHM and GW problems joined in an expert committee under the patronage of the German Society for Non-Destructive Testing. An initiated online survey among more than 700 experts and users reveals the hurdles hindering the practical application of GWbased SHM. Firstly, methods for proof of reliability of SHM approaches are missing. Secondly, detailed understanding of phenomenological described wave-damage interactions is needed. Additionally, there are significant unsolved implementation issues and unsolved problems of signal processing including handling of environmental influences. To enable substantial proof of reliability without unaffordable experimental effort also efficient simulation tools including realistic damage interaction are needed, enabling the joint use of experimental and simulated data to predict the capabilities of the Monitoring system. Considering these issues, the committee focusses on simulation, signal processing, as well as probability of detection and standardization. In the presented work, recent activities of the expert committee starting with survey results are summarized. An open access data basis of life-like measurements is presented to allow testing and comparison of signal processing and simulation algorithms. Finally, a strategy for efficient proof of reliability increasing the acceptance of SHM in industry and for successful Integration of SHM into real-world engineering structures is proposed. T2 - The 12th International Workshop on Structural Health Monitoring (IWSHM) CY - Stanford, California, USA DA - 10.09.2019 KW - Structural Health Monitoring KW - Ultrasonic Guided Waves KW - Non-Destructive Testing KW - Survey KW - Probability of Detection KW - Reliability PY - 2019 SP - 1 EP - 10 AN - OPUS4-49232 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Algernon, D. A1 - Arndt, R.W. A1 - Denzel, W. A1 - Ebsen, B. A1 - Feistkorn, S. A1 - Friese, M. A1 - Große, C.U. A1 - Kathage, S. A1 - Keßler, S. A1 - Köpp, Christian A1 - Küttenbaum, Stefan A1 - Lohse, C. A1 - Maack, Stefan A1 - Niederleithinger, Ernst A1 - Schickert, M. A1 - Schröder, G. A1 - Taffe, A. A1 - Timofeev, Juri A1 - Walther, A. A1 - Wilcke, M. A1 - Wolf, J. A1 - Wöstmann, Jens T1 - Test specimen concepts in regard to quality assurance and validation of nondestructive testing in civil engineering N2 - The process of ensuring reliability of NDT applications contains various aspects, such as determining the performance and probability of success, the uncertainty in measurement, the provision of clear and functional procedures and ensuring the correct application accordingly. Test specimens have become powerful elements in supporting many of these aspects. Within the committee for NDT in Civil Engineering (NDT-CE) of the German Society for Nondestructive Testing (DGZfP), the subcommittee on Quality Assurance (UA-QS) therefore addresses the design and the integration of test specimens in the quality assurance process. Depending on the specific purpose, the requirements on test specimens can vary significantly based on the defined simulated scenario. The most prominent purposes of test specimens might be seen in providing references for inspection systems in regard to function control, calibration and validation. Further aspects can be parametric studies, basic investigation of physical principles related to NDT or a simplified and therefore comprehensive demonstration of inspection concepts (e.g. for teaching purposes). The specific purpose of a test specimen dictates the requirements regarding its conception, including the exact design, the material or the fabrication accuracy and the conditioning. In the development of a general guideline by the UA-QS for application-specific procedures and their validation, the use of test specimens is addressed and specific concepts for the design of test specimens are made. This includes the analysis of the measurement process regarding any given application, deriving an adequate calibration approach for it and designing test specimens (calibration specimens) accordingly. Furthermore, it includes the validation of the procedure taking into account all conditions related to the specific application in the field. The validation requires a statistically sufficient number of trials. Thorough evaluation of each trial can only be established if the ground-truth is known. Therefore, test specimens providing a realistic but controlled simulation of the inspection problem are valuable and indispensable elements in the validation process. The requirement of being fully realistic will often not be possible to fulfill due to practical restrictions. Any aspect that cannot be included in the simulation realistically needs to be simulated conservatively. This again, requires a sufficient understanding of the inspection principle and technique to ensure conservativeness. Among other quality-assurance-related aspects, the UA-QS establishes concepts and guidelines regarding sound and efficient approaches for the specific purposes of test specimens. This subcommittee brings together representatives of different Groups along the entire value chain of NDT-CE, including researchers, practitioners, manufacturers and clients. They all work together in establishing a common understanding and level of quality assurance in the industry. T2 - SMT and NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.08.2018 KW - Quality assurance KW - Procedure KW - Reliability KW - Validation KW - Reference specimen PY - 2019 UR - https://asnt.org/smt18papers SN - 978-1-57117-456-7 VL - 11/19 SP - 39 EP - 48 PB - The American Society for Nondestructive Testing, Inc. CY - Columbus, OH, USA AN - OPUS4-47240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Algernon, D. A1 - Arndt, R.W. A1 - Denzel, W. A1 - Ebsen, B. A1 - Feistkorn, S. A1 - Friese, M. A1 - Große, C.U. A1 - Kathage, S. A1 - Keßler, S. A1 - Köpp, Christian A1 - Küttenbaum, Stefan A1 - Lohse, C. A1 - Maack, Stefan A1 - Niederleithinger, Ernst A1 - Schickert, M. A1 - Schröder, G. A1 - Taffe, A. A1 - Timofeev, Juri A1 - Walther, A. A1 - Wilcke, M. A1 - Wolf, J. A1 - Wöstmann, Jens T1 - NDT procedures in relation to quality assurance and validation of nondestructive testing in civil engineering N2 - The field of non-destructive testing of civil structures (NDT-CE) has been continuously growing. Due to the complexity and diversity of civil constructions as well as the heterogeneity of concrete, specific standards or guidelines for the application of modern NDT-CE are still missing. The development of individual solutions is the current approach, which is just as challenging as it is common for NDT-CE. With the increasing development and commercialization of NDT-CE technology, the group of practitioners is growing. To ensure a good level of quality in the industry, it appears necessary to establish adequate means. Naturally, the performance of NDT-CE methods regarding a specific application is strongly dependent on choosing the most suitable inspection technique and applying it correctly, generally referred to as the inspection procedure in the field of NDT. There are well-defined guidelines regarding procedure documentation and handling in many fields of NDT (e.g. nuclear, aerospace or automotive) according to the high importance of procedures in assuring a successful and reliable application. For a long time, this has not always been the case with NDT-CE, which is still considered a unique discipline of NDT. Part of the reason for that might be the young development state of NDTCE, the heterogeneity of building materials like concrete, timber or masonry as a material and the diversity of civil structures. In consequence, NDT-CE procedure development is considered challenging. Among other aspects, addressed in the subcommittee on Quality Assurance (UA-QS) within the committee for NDT-CE of the German Society for Nondestructive Testing (DGZfP), part of its work aims at establishing an adequate basis for NDT-CE procedure development. While some of the highly developed approaches from other industries are taken into consideration, they need to be analyzed regarding their suitability for NDT-CE and adapted accordingly. For a procedure to be as defined as possible, it needs to contain sufficient information, such as the scope and limitations regarding material, geometry and condition of the test object, inspection parameters, calibration, data acquisition, analysis criteria as well as requirements regarding the inspection personnel. For a successful implementation in the field, it is important to define the specific procedure as precisely as possible. Despite the necessity of a great amount of information to be included, the procedure needs to be suitable for efficient field application. The UA-QS is developing a guideline for NDT-CE procedures suitable for application in this field of NDT to ensure correct and reproducible application. To demonstrate and evaluate this concept, specific examples of procedures are also produced. In particular, the UA-QS has developed a procedure for the detection and positioning of tendon ducts using Ground Penetrating Radar (GPR). This procedure is tested regarding the practical applicability in a roundrobin on a defined type of reference test block. T2 - SMT and NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.08.2018 KW - Quality assurance KW - Procedure KW - Reliability KW - Validation KW - Reference specimen PY - 2019 UR - https://asnt.org/smt18papers SN - 978-1-57117-456-7 VL - 11/19 SP - 31 EP - 38 PB - The American Society for Nondestructive Testing, Inc. CY - Columbus, OH, USA AN - OPUS4-47239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Niederleithinger, Ernst A1 - Wiggenhauser, Herbert T1 - The LAUS: First Applications of a New System for Ultrasonic Imaging of Very Concrete Structures N2 - The LAUS (Large Aperture Ultrasonic System) has been developed to image very thick concrete structures, which are not accessible for commercial systems. The device and the corresponding software is the result of joint Research of BAM, an ultrasonic instrument manufacturer and University of Kassel, Germany. It consists of 12 separate Arrays of 32 point-contact shear wave transducers each, which can be deployed in flexible configurations. Each array is combined with battery and transmitter, receiver and wireless communication electronics. Three case histories are presented. First the system was deployed on a 5-m thick heavily reinforced foundation slab. The reflection of the slab’s bottom was imaged clearly. In addition, a multiple reflection was registered, thus giving hope that even thicker elements might be imaged by the instrument. Second, the LAUS was used to investigate a massive bridge girder where a heavy rainstorm during concreting had led to imperfections that were visible after removing the formwork was removed. The LAUS could image tendon ducts in 1.8m depth and the backwall closely behind them. Some limited areas showed blurred reflections and were checked by drill holes; these areas were affected by diffuse damage which could be repaired by injections. Third, a large retaining wall was checked for thickness. Meanwhile, the LAUS has been used in underground waste deposits (nuclear and other) for quality assurance of sealing plugs. A confirmed penetration depth of about 7 m has been reached. T2 - SMT and NDT-CE 2018 CY - New Brunswick, NJ, USA DA - 27.08.2018 KW - LAUS (Large Apertur Ultrasonic System) KW - Ultrasonic echo KW - Deep penetration KW - Concrete PY - 2019 UR - https://asnt.org/smt18papers SN - 978-1-57117-456-7 VL - 11/19 SP - 208 EP - 213 PB - The American Society for Nondestructive Testing, Inc. CY - Columbus, OH, USA AN - OPUS4-47238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bulling, Jannis A1 - Prager, Jens T1 - Bestimmung der Rissgeometrie bei der zerstörungsfreien Ultraschallprüfung mit geführten Wellen N2 - In der zerstörungsfreien Prüfung werden in zunehmendem Maße geführte Ultraschallwellen zur Lokalisation von Fehlstellen genutzt. Geführte Ultraschallwellen zeichnen sich dadurch aus, dass sie große Distanzen innerhalb des zu prüfenden Bauteiles zurücklegen können. Das Ultraschallwellenfeld setzt sich dabei aus verschieden Moden zusammen. Etablierte Prüfverfahren mit geführten Wellen ermitteln häufig nur die Position der Fehlstelle, wobei die Laufzeiten der reflektierten Signale ausgewertet wird. Modenumwandlung bleibt dabei zumeist unberücksichtigt. Die Charakterisierung der Fehlstelle, zum Beispiel hinsichtlich der Länge eines Risses, ist dagegen herausfordernd. Aussagekräftige Zusammenhänge zwischen der Dimension oder Geometrie der Fehlstelle und ihrer Interaktion mit der Ultraschallwelle zu finden, ist Teil aktueller Forschung. Insbesondere eine Betrachtung der Moden höherer Ordnung und deren Amplitudenverhältnisse kann beim Aufspüren dieser Zusammenhänge hilfreich sein. Im Beitrag werden zunächst die Zusammenhänge zwischen den beiden fundamentalen Moden in einer isotropen Platte und der Länge eines Risses untersucht. Aus den Ergebnissen wird ein inverses Verfahren motiviert. Ein Algorithmus wird vorgestellt, der die Risslänge im Modell solange variiert, bis er die modalen Zusammenhänge einer Vorgabe oder einer Messung rekonstruiert. Die eingesetzte Scaled Boundary Finite Element Method ermöglicht dabei eine sehr kurze Rechenzeit in jeden Optimierungsschritt. Zusätzlich ermöglicht die Methode eine Auswertung der modalen Zusammenhänge ohne Postprocessing, was die Rechenzeiten weiter verkürzt. T2 - DAGA 2019 - 45. Jahrestagung für Akustik CY - Rostock, Germany DA - 18.03.2019 KW - Geführte Ultraschallwellen KW - Zerstörungsfreien Prüfung KW - Scaled Boundary Finite Element Method PY - 2019 VL - 45 SP - 1063 PB - Deutsche Gesellschaft für Akustik e.V. AN - OPUS4-47783 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -