TY - CONF A1 - Gaal, Mate T1 - Focussed sound field of thermoacoustic transmitters N2 - The thermoacoustic effect offers a method for selectively exciting broadband and focused ultrasonic waves, which can be utilized in air-coupled ultrasonic testing of lightweight components that might otherwise sustain damage from liquid couplants. Thermoacoustic transmitters are composed of an electrically conductive layer deposited on an insulating substrate. When electrical pulses are applied, the conductive layer heats, briefly warming the adjacent air and inducing thermal expansion, which generates an acoustic wave. In testing applications, the thermoacoustic transmitter is positioned at the focal distance to the structure under examination, where the resolution of the resulting ultrasonic image is influenced by the focus diameter. To optimize imaging resolution, understanding the focusing characteristics of thermoacoustic transmitters is essential. In this study, thermoacoustic transmitters with an indium tin oxide (ITO) layer on a quartz glass substrate were developed. Geometrical parameters, including substrate curvature and conductive layer thickness, along with electrical excitation parameters, were systematically varied to investigate their impact on the sound field up to approximately 1 MHz. The results indicate that, among the parameters studied, substrate curvature exerts the most significant influence on the sound field. T2 - DAS-DAGA Tagung CY - Copenhagen, Denmark DA - 17.03.2025 KW - Air-coupled ultrasound KW - Thermoacoustic transmitter KW - Focussed transducer PY - 2025 AN - OPUS4-63093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rogge, Andreas A1 - Meng, Birgit A1 - Kühne, Hans-Carsten T1 - 63. DAfStb-Forschungskolloquium in der BAM - Green Intelligent Building N2 - Das jährlich im Herbst an wechselnden Forschungsstandorten stattfindende DAfStb-Forschungskolloquium wurde im Jahr 2024 von der BAM Bundesanstalt für Materialforschung und -prüfung in Berlin ausgerichtet. Unter der Überschrift „Green Intelligent Building“ referierten rd. 35 Vortragende in fünf Sitzungen unterschiedlicher Thematik über verschiedene betonbezogene Forschungsschwerpunkte in der BAM. Anhand der überwiegend von Doktoranden und Post-Docs dargebotenen Vorträge konnten sich die Teilnehmerinnen und Teilnehmer ein aktuelles Bild von der Qualität der wissenschaftlichen Arbeit und der hervorragenden Forschungsmöglichkeiten in der BAM machen. Durch die Vernetzung unterschiedlich ausgerichteter Fachbereiche innerhalb der BAM werden Synergie-Effekte genutzt. Analytische, baustoffliche, konstruktive, umweltorientierte und auf die Verfahrensentwicklung ausgerichtete Bereiche der BAM forschen gemeinsam zum Thema Stahlbetonbau. Es folgen ausführliche Zusammenfassungen der Tagungsinhalte. T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building CY - Berlin, Germany DA - 16.10.2024 KW - Bauteile KW - Bauwerke KW - Beton KW - Chemie der Bindemittel KW - Digitalisierung im Bauwesen KW - Green Intelligent Building KW - Innovative Technologien KW - Klimafreundliche Bindemittel KW - Ressourcenschonung PY - 2025 SN - 0005-9846 VL - 75 IS - 4 SP - 128 EP - 129 PB - concrete content UG CY - Schermbeck AN - OPUS4-63109 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wosniok, Aleksander T1 - Auftakttreffen FOSsure „ Faseroptische Sensoren zur sicheren Zustandsbewertung von Massivbrücken“ N2 - Vorstellung der Vorarbeiten und Kernkompetenzen des Fachbereiches 8.6 hinsichtlich der Zustandsüberwachung von Brückenbauwerken im Rahmen eines Auftakttreffens im Forschungsprojekt FOSsure. T2 - Kick-off-Treffen FOSsure CY - Dresden, Germany DA - 16.04.2025 KW - DFOS KW - faseroptische Sensoren KW - Brückenmonitoring KW - Ortverteilte akustische Sensorik KW - COTDR PY - 2025 AN - OPUS4-62975 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schackmann, Oliver A1 - Márquez Reyes, Octavio A. A1 - Memmolo, Vittorio A1 - Lozano, Daniel A1 - Prager, Jens A1 - Moll, Jochen A1 - Kraemer, Peter T1 - Machine learning strategies with ensemble voting for ultrasonic damage detection in composite structures under varying temperature or load conditions N2 - In recent years, the development of machine learning (ML) techniques has led to significant progress in the field of structural health monitoring with ultrasonic-guided waves. However, a number of challenges still need to be resolved for reliable operation in realistic settings. In this work, we consider the complex problem of experimental damage detection under varying temperature or load conditions where damage locations are not included in the training set. The ML techniques proposed here include supervised and unsupervised methods originally developed for image and time series classification combined with ensemble voting. A performance demonstration of the ML techniques is presented using benchmark datasets from the open-guided waves platform. The unsupervised approach is then applied to a new dataset from an experimental campaign carried out on a composite over-wrapped pressure vessel used for hydrogen storage with real defects. Results show that ensemble voting enables the effective combination of the predictions of multiple transducer pairs, even with a limited number of strong individual classifiers. When applied to unsupervised learning, this returns high accuracy also when real damage over the structure is considered. KW - Structural-Health-Monitoring KW - Ultrasonic guided waves PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631571 DO - https://doi.org/10.1177/14759217251333066 SN - 1741-3168 SP - 1 EP - 19 PB - Sage Publications AN - OPUS4-63157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jafari, Abbas A1 - Vlachas, K. A1 - Chatzi, E. A1 - Unger, Jörg F. T1 - A Bayesian framework for constitutive model identification via use of full field measurements, with application to heterogeneous materials N2 - In this paper, we present a Bayesian framework for the identification of the parameters of nonlinear constitutive material laws using full-field displacement measurements. The concept of force-based Finite Element Model Updating (FEMU-F) is employed, which relies on the availability of measurable quantities such as displacements and external forces. The proposed approach particularly unfolds the advantage of FEMU-F, as opposed to the conventional FEMU, by directly incorporating information from full-field measured displacements into the model. This feature is well-suited for heterogeneous materials with softening, where the localization zone depends on the random microstructure. Besides, to account for uncertainties in the measured displacements, we treat displacements as additional unknown variables to be identified, alongside the constitutive parameters. A variational Bayesian scheme is then employed to identify these unknowns via approximate posteriors under the assumption of multivariate normal distributions. An optimization problem is then formulated and solved iteratively, aiming to minimize the discrepancy between true and approximate posteriors. The benefit of the proposed approach lies in the stochastic nature of the formulation, which allows to tackle uncertainties related to model parameters and measurement noise. We verify the efficacy of our proposed framework on two simulated examples using gradient damage model with a path-dependent nonlinear constitutive law. Based on a nonlocal equivalent strain norm, this constitutive model can simulate a localized damage zone representing softening and cracking. The first example illustrates an application of the FEMU-F approach to cracked structures including sensitivity studies related to measurement noise and parameters of the prior distributions. In this example, the variational Bayesian solver demonstrates a sizable advantage in terms of computational efficiency compared to a traditional least-square optimizer. The second example demonstrates a sub-domain analysis to tackle challenges associated with limited domain knowledge such as uncertain boundary conditions. KW - Constitutive model identification KW - Full-field measurements KW - Variational Bayes KW - Force-based finite element model updating KW - FEMU-F PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615476 DO - https://doi.org/10.1016/j.cma.2024.117489 SN - 1879-2138 VL - 433 IS - Part A SP - 1 EP - 32 PB - Elsevier B.V. AN - OPUS4-61547 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schneider, Ronald A1 - Simon, Patrick A1 - Herrmann, Ralf A1 - Hille, Falk A1 - Baeßler, Matthias T1 - Bestandteile Digitaler Zwillinge im Erhaltungsmanagement von Verkehrsbrücken T1 - Components of digital twins in the operation and maintenance management of traffic bridges N2 - Digitale Zwillinge werden zukünftig ein integraler Bestandteil des Erhaltungsmanagements von Verkehrsbrücken sein. In diesem Beitrag wird argumentiert, dass sie nicht nur als digitale Abbilder physikalischer Bauwerke verstanden werden sollten, sondern als eine umfassende digitale Methode, die durch die Integration von Datenerfassung, Erhaltungsmaßnahmen, Datenmanagement, Bauwerksbewertung und Entscheidungsunterstützung die Bauwerksüberwachung und ‐erhaltung verbessert. In diesem Zusammenhang wird betont, dass der Übergang von der reaktiven zur prädiktiven Erhaltung durch den Einsatz von Digitalen Zwillingen nur dann realisierbar ist, wenn neben den erforderlichen diagnostischen und prognostischen Zustandsanalysen auch Methoden zur Optimierung von Entscheidungen über Datenerfassung und Erhaltungsmaßnahmen implementiert werden. Zur Veranschaulichung der Diskussion werden in diesem Beitrag exemplarisch zwei Bestandteile eines Digitalen Zwillings für das Erhaltungsmanagement von Verkehrsbrücken am Beispiel einer Eisenbahnbrücke demonstriert. Dabei wird zum einen gezeigt, wie Monitoringdaten mittels eines Datenmanagementsystems strukturiert verwaltet und für angeknüpfte Analysen bereitgestellt werden. Zum anderen erfolgt im Rahmen einer bauwerksspezifischen Einwirkungsermittlung eine Zugidentifikation anhand von gemessenen Schwellenschwingungen. N2 - Digital twins will become an integral part of the operation and maintenance management of traffic bridges in the future. This paper argues that they should not only be understood as digital representations of physical structures but as a digital methodology that enhances the operation and maintenance of bridges through the integration of data collection, maintenance actions, data management, structural assessment, and decision support. In this context, it is emphasized that the transition from reactive to predictive maintenance using digital twins can only be achieved if, in addition to the necessary diagnostic and prognostic condition analyses, methods for optimizing decisions on data collection and maintenance actions are also implemented. To illustrate this discussion, two key components of a digital twin for the operation and maintenance management of traffic bridges are demonstrated using a railway bridge as an example. First, it is shown how monitoring data can be systematically managed and made available for subsequent analyses through a data management system. Second, train identification based on measured sleeper vibrations is conducted as part of an object-specific load assessment. KW - Digitale Zwillinge KW - Erhaltung KW - Inspektion KW - Monitoring KW - Brücken PY - 2025 DO - https://doi.org/10.1002/bate.202400101 SN - 1437-0999 SP - 1 EP - 11 PB - Ernst & Sohn CY - Berlin AN - OPUS4-62837 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schneider, Ronald T1 - Digitaler Zwilling im Erhaltungsmanagement von Straßenbrücken N2 - Digitale Zwillinge werden zukünftig ein integraler Bestandteil des Erhaltungsmanagements von Straßenbrücken sein. In diesem Beitrag wird argumentiert, dass sie nicht nur als digitale Abbilder physikalischer Bauwerke verstanden werden sollten, sondern als eine umfassende digitale Methode, die durch die Integration von Datenerfassung, Erhaltungsmaßnahmen, Datenmanagement, Bauwerksbewertung und Entscheidungsunterstützung die Bauwerksüberwachung und -erhaltung verbessert. In diesem Zusammenhang wird betont, dass der Übergang von der reaktiven zur prädiktiven Erhaltung durch den Einsatz von Digitalen Zwillingen nur dann realisierbar ist, wenn neben den erforderlichen diagnostischen und prognostischen Zustandsanalysen auch Methoden zur Optimierung von Entscheidungen über Datenerfassung und Erhaltungsmaßnahmen implementiert werden. Zur Veranschaulichung der Diskussion werden in diesem Beitrag exemplarisch zwei Bestandteile eines Digitalen Zwillings für das Erhaltungsmanagement von Verkehrsbrücken am Beispiel einer Eisenbahnbrücke demonstriert. Dabei wird zum einen gezeigt, wie Monitoringdaten mittels eines Datenmanagementsystems strukturiert verwaltet und für angeknüpfte Analysen bereitgestellt werden. Zum anderen erfolgt im Rahmen einer bauwerksspezifischen Einwirkungsermittlung eine Zugidentifikation anhand von gemessenen Schwellenschwingungen T2 - Workshop „Digitaler Zwilling im Lebenszyklusmanagement" der AG BIM in der Bauwerkserhaltung des Koordinierungsausschusses Erhaltung (KoA-Erhaltung) der B/L-DB Konstruktiver Ingenieurbau CY - Potsdam, Germany DA - 09.04.2025 KW - Digitale Zwillinge KW - Erhaltung KW - Inspektion KW - Monitoring KW - Brücken PY - 2025 AN - OPUS4-62951 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - John, Elisabeth A1 - Jakob, Cordula A1 - Pott, Ursula A1 - Sando, Mona T1 - Repeatability and reproducibility challenges of isothermal heat flow calorimetry with in situ mixing N2 - Isothermal heat flow calorimetry evaluates heat development during binder reactions. It distinguishes between in situ calorimetry, where mixing occurs within the device, and ex situ calorimetry, involving externally mixed samples. Despite ex situ calorimetry being a standard method in binder research, in situ calorimetry is underutilized. This paper aims to promote its adoption by summarizing challenges related to repeatability and reproducibility and offering solutions. The initial section addresses repeatability issues caused by preventable errors, providing a structured guide for experimental design. It was found that water leakage had minimal impact, and sample size is crucial for data robustness. The second section examines operational challenges, revealing that frictional heating, affecting recorded heat, can be minimized with an optimized mixing protocol. The final part highlights that significant errors in measured data stem from signal delay and heat loss, offering methods to correct these issues for improved reproducibility in in situ calorimetric experiments. KW - In situ calorimetry PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628431 DO - https://doi.org/10.1016/j.cemconres.2025.107872 SN - 1873-3948 VL - 194 SP - 1 EP - 11 PB - Elsevier Ltd. AN - OPUS4-62843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Baeßler, Matthias A1 - Simon, Patrick T1 - Ballasted track on vibrating bridge decks: physical mechanisms, empirical findings, and a proposal for assessment N2 - This paper summarizes the key findings and physical mechanisms and provides information on open questions and the assessment of railway bridge superstructure vibrations. Bridges are classic disruption points on a railway track. If bridge superstructures are dynamically excited by train traffic, the vertical accelerations of the track must be considered. For a ballasted track, this can lead to the destabilization of the ballast track, as the bridge superstructure acts like a vibrating table. In this respect, the paper explains in more detail what is meant by destabilization, when this destabilization occurs and how various influencing parameters such as acceleration amplitude, the vibration sequence and frequency affect its occurrence. In the InBridge4EU project, gaps in knowledge such as the effect of single impulse loads are being investigated experimentally. A new test facility has been set up for this purpose, the initial results of which are presented here. An essential element in the assessment of this scenario is the stability of the track under high compression forces with simultaneous dynamic excitation of the superstructure. A new approach for the assessment of bridge vibrations with respect to lateral stability is presented. KW - Railway bridge dynamics KW - Bridge deck acceleration KW - Ballast destabilization KW - Lateral track stability KW - Track buckling PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630972 DO - https://doi.org/10.1142/S0219455425400243 SN - 0219-4554 SN - 1793-6764 IS - 2540024 SP - 1 EP - 27 PB - World Scientific CY - Singapore AN - OPUS4-63097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Herrmann, Ralf T1 - Managing Structural Health Monitoring with the Research Data Management Platform BAM Data Store N2 - Structural Health Monitoring (SHM) is an interdisciplinary challenge involving the assessment and prediction of the condition of civil structures, such as bridges, based on measurements and models. This presentation provides insight into how the BAM Data Store is used to represent a SHM project including the metadata and the monitoring data, itself. It describes the structure of the core elements of a typical SHM and introduces metadata profiles. This enables linking objects within the BAM Data Store to create a hierarchical structure. N2 - Structural Health Monitoring (SHM) ist eine interdisziplinäre Aufgabe bei der es um die Bewertung und Zustandsprognose von Bauwerken, wie z. B. Brücken, auf der Grundlage von Messungen und Modellen geht. Die Präsentation gibt einen Einblick in die Verwendung des BAM Data Stores zur Abbildung eines SHM Projekts zum Datenmanagement aller relevanten Metadaten und der Monitoringdaten selbst. Es werden die Struktur der Kernelemente eines typischen SHM beschrieben und Metadatenprofile für diese vorgestellt. Im BAM Data Store werden damit die strukturierte Verknüpfung von Objekten ermöglicht, um eine hierarchische Struktur zu erzeugen. T2 - Data Store Days 2025 CY - Berlin, Germany DA - 09.04.2025 KW - Structural Health Monitoring (SHM) KW - BAM Data Store KW - Verkehrsinfrastrukturen PY - 2025 AN - OPUS4-62942 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Andrés Arcones, Daniel T1 - Incorporating model form uncertainty in digital twins for reliable parameter updating and quantitites of interest analysis N2 - With the rapid adoption of Digital Twins in recent years, simulation models designed to replicate real-world physical systems have become increasingly common. To achieve accurate representations, it is typically necessary to update model parameters based on observations collected from sensors or measurements of the physical asset. However, no model can fully capture the infinitely complex nature of reality. As a result, quantifying the uncertainty in model predictions is essential for reliable decision-making. Bayesian updating frameworks provide an appealing approach for parameter calibration, inherently accounting for such uncertainties. One often-overlooked source of error is model form uncertainty. This type of uncertainty arises from the fundamental discrepancies between the model and reality, stemming from the assumptions and simplifications made during model construction. Ignoring model form uncertainty can lead to overly confident predictions that fail to accurately reflect sensor observations. To address this, we propose an embedded model form uncertainty framework that attributes the model variability to a stochastic extension of the model's latent parameters. This approach enables the quantification of uncertainties that can be represented by a variation in the model parameters. Of particular interest are scenarios involving noisy observations or additional discrepancies that cannot be directly integrated into the model. By incorporating uncertainty through the parameters, this method not only quantifies uncertainty in predictions but also propagates model form uncertainty to other Quantities of Interest (QoI) that rely on the same model or its parameters. Consequently, QoI computations yield more reliable values, accounting for the potential uncertainties introduced by imperfect models during parameter updating. Moreover, this approach facilitates a more comprehensive statistical analysis of QoI distributions, offering deeper insights into the model's reliability and highlighting areas for potential improvement. By incorporating model form uncertainty, decision-makers can achieve a more robust and nuanced understanding of system behavior and prediction quality. T2 - 95th Annual Meeting oft eh International Association of Applied Mathematics and Mechanics (GAMM) CY - Poznan, Poland DA - 07.04.2024 KW - Unsicherheiten Quantifizierung KW - Brückenüberwachung KW - Digitaler Zwilling PY - 2025 AN - OPUS4-62972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pirskawetz, Stephan T1 - Digital acoustic twin for prestressed concrete structures N2 - In den 1950er Jahren setzte sich die Spannbetonbauweise für Brücken mit größeren Spannweiten durch. Heute existieren im deutschen Bundesfernstraßennetz ca. 21.000 Spannbetonbrücken. Die mangelnde Erfahrung in der Anfangszeit dieser Bauweise stellt uns heute vor Probleme hinsichtlich einer Kombination aus Korrosion und Ermüdung der Spannglieder. Hauptursachen sind Spannungsrisskorrosion, deutlich gewachsene Verkehrslasten sowie ungenügende Annahmen zu Temperaturlasten. Insbesondere Spanndrahtbrüche infolge Spannungsrisskorrosion können zu einem Strukturversagen ohne Ankündigung führen. Spannstähle mit einer starken Gefährdung für Spannungsrisskorrosion wurden in der Bundesrepublik bis 1965, in der ehemaligen DDR bis Ende der 1980er Jahre verbaut. Um katastrophale Schadensfälle zu verhindern, müssen Bauwerke unter Verdacht auf Spannungsrisskorrosion in Kombination mit unzureichendem Ankündigungsverhalten überwacht werden. Derzeit ist die Schallemissionsanalyse die einzige zuverlässige und ökonomisch vertretbare Überwachungsmethode. Damit kann der sichere Betrieb der Bauwerke über die verbleibende Nutzungsdauer gewährleistet werden. Die DGZfP-Richtlinie SE05 “Detektion von Spanndrahtbrüchen mit Schallemissionsanalyse” beschreibt detailliert Planung, Installation und Betrieb solcher Monitoringsysteme. Im Projekt SimAS “Digitaler Zwilling zur Simulation der Ausbreitung akustischer Wellen in Spannbetonelementen” werden die Grundlagen für eine Optimierung der Monitoringsysteme auf Basis der Schallemissionsanalyse gelegt. Eine akustische Simulation der Struktur und deren Fusion mit Messdaten unterstützt sowohl die vorbereitenden akustischen Analysen der Brücken als auch die Planung der Monitoringsysteme und die Drahtbrucherkennung. T2 - SCHALL 25 – Schallemissionsanalyse und Zustandsüberwachung mit geführten Wellen CY - Dresden, Germany DA - 27.03.2025 KW - Acoustic Emission KW - Spannbeton KW - Brücke KW - Digitaler akustischer Zwilling KW - Schallausbreitung KW - Schallemissionsanalyse PY - 2025 AN - OPUS4-62835 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fiedler, Max A1 - Pirskawetz, Stephan A1 - Kaplan, Felix A1 - Holst, Ralph A1 - Saloga, Katrin A1 - Schmidt, Sebastian A1 - Sodeikat, Christian T1 - Detektion von Spanndrahtbrüchen mit Schallemissionsanalyse T1 - Detection of Wire Breaks using Acoustic Emission Analysis - The New Guideline SE 05 of the German Society for Non- Destructive Testing (DGZfP) N2 - AbstractSpannungsrisskorrosion stellt Brückenbetreiber vor immense Herausforderungen, da sie zu gravierenden Schäden an den Spanngliedern führen kann und gleichzeitig die Methoden zur frühzeitigen Schadenserkennung und Tragfähigkeitskontrolle stark eingeschränkt sind. In diesem Kontext hat sich die Schallemissionsanalyse (SEA) zur Detektion von Spanndrahtbrüchen als bedeutsame Methode etabliert. Diese Technologie bietet einzigartige Vorteile und kann einen wichtigen Beitrag zur Sicherstellung des Weiterbetriebs gefährdeter Bauwerke liefern. Gleichzeitig erfordert die Anwendung der SEA tiefgehende spezialisierte Fachkenntnisse. Mit der zunehmenden Verbreitung und dem steigenden Interesse an dieser Methode ist auch der Bedarf an standardisierten Prozessen und Qualitätskontrollen gewachsen. Diesen Bedarf hat der Fachausschuss Schallemissionsprüfung der DGZfP erkannt und die Richtlinie  SE 05 entwickelt. Diese Richtlinie setzt klare Standards und bietet umfassende Anleitung für die Implementierung und Anwendung der Schallemissionsanalyse zur Detektion von Spanndrahtbrüchen. N2 - Stress corrosion cracking confronts bridge operators with immense challenges, as it can lead to severe damage to the tendons while the methods for early damage detection and load-bearing capacity control are highly limited. In this context, Acoustic Emission Analysis (AEA) has established itself as an important method for detecting wire breaks. This technology offers unique advantages and can make a vital contribution to ensuring the continued operation of endangered structures. However, the application of AEA requires deep specialized expertise. With the increasing adoption and growing interest in this method, the need for standardized processes and quality controls has also grown. The DGZfP’s Acoustic Emission Testing Committee recognized this need and developed Guideline SE 05. This guideline sets clear standards and provides comprehensive guidance for the implementation and application of Acoustic Emission Analysis for detecting wire breaks. KW - Brücke KW - Spannungsrisskorrosion KW - Monitoring KW - Schallemission KW - Spanndrahtbrucherkennung KW - Schadensdetektion KW - Richtlinie SE 05 KW - DGZfP PY - 2025 DO - https://doi.org/10.1002/best.202400098 SN - 1437-1006 VL - 119 IS - 2 SP - 150 EP - 164 PB - Ernst & Sohn GmbH CY - Berlin AN - OPUS4-62753 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Recknagel, Christoph A1 - Eilers, Manfred A1 - Hoppe, Johannes A1 - Cetinkaya, Reha A1 - Machill, Nicole A1 - Weitz, Dennis A1 - Zscherpe, Oliver A1 - Sikinger, Thomas A1 - Loher, erich A1 - Oelerich, Martin A1 - Schäfer, Volker A1 - Schäfer, Thorsten A1 - Uslu, Cenk A1 - Virnau, Lucas A1 - Dudenhöfer, Bernd A1 - Rückert, Phillip A1 - Alte-Teigeler, Ralf A1 - Rau, Richard T1 - Merkblatt für die Herstellung von Abdichtungssystemen aus hohlraumreichen Asphalttraggerüsten mit nachträglicher Verfüllung (HANV) für Ingenieurbauten aus Beton N2 - Konventionelle Regelbauweisen für die Ausbildung von Abdichtungssystemen auf Brücken- und anderen Ingenieurbauwerken aus Beton machen signifikante material- und systembedingte Einbau- und Sperrzeiten erforderlich. Das innovative Abdichtungssystem „Hohlraumreiches Asphalttraggerüst mit nachträglicher Verfüllung“ (kurz: HANV) bietet eine deutliche Zeitersparnis von Ausführung bis Verkehrsfreigabe. Gleichzeitig zeichnet sich diese Bauweise mit einer hohen Deformationsbeständigkeit gegenüber Schwerlastverkehr aus. Auf der Grundlage eines mittlerweile ausgeprägten Erfahrungshintergrundes wird mit Hilfe des aufgestellten Regelwerkes der Baupraxis eine qualitätssichere Ausführung mit gütegesicherter Funktionalität zur Verfügung gestellt. KW - Abdichtungssysteme KW - Verkehrs-Infrastrukutur KW - Ingenieurbauwerke aus Beton PY - 2025 SN - 978-3-86446-421-8 VL - 2025 IS - 1 SP - 3 EP - 40 PB - FGSV-Verlag CY - Wesselinger Straße 15-17 in 50999 Köln ET - 1. Auflage AN - OPUS4-62798 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Unger, Jörg F. T1 - Bayesian model updating for predictive digital twins under model form uncertainty N2 - Simulation models are an essential tool to support decision making in civil engineering. Since the structures are often unique, full scale experimental validations are very costly or even impossible and the consequences of failure are severe, the simulation models have to be reliable and should provide results with sufficient safety margins, often resulting in very conservative designs. For innovative approaches such as 3D concrete printing, these models are even more important - supporting not only an a priori design optimization, but provide the option for a real-time process control or a quality assessment in a post-processing by evaluating the impact of discrepancies between the as-designed and as-built structures on quantities of interest. The simulation models are typically parameterized, and with the inclusion of noisy measurement data and prior knowledge of model parameters, Bayesian methods allow for the estimation of posterior parameter distributions. However, engineers are often interested in quantities of interest (QoIs) that are either not measured at the location of interest or cannot be measured directly, such as maximum stresses, failure probabilities or remaining useful life. Propagating posterior parameter distributions to these QoIs generally underestimates their uncertainty, especially when dealing with large datasets which is typical for digital twins with a constant data flow. One of the reasons is the fact that model form uncertainty is usually neglected. However, for complex structures involving interacting physical processes, model form uncertainty due to modeling assumptions and simplifications is unavoidable to ensure computational tractability of the simulation models. As a consequence, it is required to incorporate these additional uncertainties in the computational approach and model updating procedure. This work presents embedded Bayesian methods that integrate model form uncertainty into the parameter space by transforming the deterministic model into a stochastic one [1]. The propagation of these parameter distributions through the model is achieved using polynomial chaos expansion techniques. Additionally, the likelihood is redefined using Approximate Bayesian Computation (ABC) methods. The proposed methods are applied to several structural engineering case studies, ranging from model calibration for 3D concrete printing based on laboratory tests to the digital twin of the Nibelungen bridge in Worms, Germany. T2 - Digital Twins in Engineering & Artificial Intelligence and Computational Methods in Applied Science, DTE - AICOMAS 2025 CY - Paris, France DA - 17.02.2025 KW - Bayesian inference KW - Model updating KW - Parameter estimation KW - Model form uncertainty PY - 2025 AN - OPUS4-62748 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baeßler, Matthias T1 - Maßgeblicher Einfluss geotechnischer Interaktionsprobleme auf den Tragwerksentwurf: Zwei spezielle Fallbeispiele N2 - Geotechnische Interaktionsprobleme können den Entwurf eines Tragwerks maßgeblich beeinflussen. Anhand zweier Fallbeispiele - dem Schotteroberbau auf Brücken im HGV und der Installation großer Monopiles - werden aktuelle Fälle aus dem Forschungsrepertoire der BAM vorgestellt. T2 - Geotechnische Seminarreihe am IBF des KIT CY - Karlsruhe, Germany DA - 23.01.2025 KW - Schotter auf Brücken im Hochgeschwindigkeitsverkehr KW - Pfahlfussbeulen KW - Beschleunigungsgrenzwert KW - Rammung KW - Monopiles PY - 2025 AN - OPUS4-62451 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nandish, Ranjith A1 - Knaust, Christian A1 - Zehfuß, Jochen T1 - Numerical Investigations of a Large Fire Exposure Crib Test—Presenting Different Pyrolysis Modelling Methodologies and Numerical Results N2 - ABSTRACTThe need for numerical‐based approaches to investigate the fire behaviour in buildings with combustible components is growing due to the increasing use of timber by the construction industry to meet the ‘Climate Action Plan 2050’. This requires consideration of the complex kinetic processes that take place during the burning of the wood in the numerical models. This is accomplished by using computational fluid dynamics (CFD) to numerically model the material pyrolysis and combustion processes. This article presents three different approaches for simulating the behaviour of a wood crib fire using the fire dynamics simulator (FDS). These approaches are based on either prescribing the burning rate of the wood directly from the physical experiments or using the kinetic parameters to govern the underlying processes, such as pyrolysis. Wooden crib fire experiments carried out by the RISE Research Institute in Sweden inside the combustion chamber that were used to validate all the methods. The numerical results from the method, that utilised the experimentally determined burning rate, were in good agreement with the experimental results, with a maximum deviation of 6% in the case of HRR. On the other hand, the model that needs kinetic parameters as its input has shown maximum discrepancies of 12% and 33% compared to experimental results. These methods are sensitive to the input parameters and the extent of dependency needs further investigation. KW - Pyrolysis KW - Wood combustion KW - Wood fire loads KW - Wooden buildings PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626567 DO - https://doi.org/10.1002/fam.3287 SN - 1099-1018 VL - 49 IS - 4 SP - 371 EP - 387 PB - John Wiley & Sons Ltd. AN - OPUS4-62656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Ahmadzadeh, Majid A1 - Weise, Matthias T1 - Focussed sound field of thermoacoustic transmitters N2 - The thermoacoustic effect offers a method for selectively exciting broadband and focused ultrasonic waves, which can be utilized in air-coupled ultrasonic testing of lightweight components that might otherwise sustain damage from liquid couplants. Thermoacoustic transmitters are composed of an electrically conductive layer deposited on an insulating substrate. When electrical pulses are applied, the conductive layer heats, briefly warming the adjacent air and inducing thermal expansion, which generates an acoustic wave. In testing applications, the thermoacoustic transmitter is positioned at the focal distance to the structure under examination, where the resolution of the resulting ultrasonic image is influenced by the focus diameter. To optimize imaging resolution, understanding the focusing characteristics of thermoacoustic transmitters is essential. In this study, thermoacoustic transmitters with an indium tin oxide (ITO) layer on a quartz glass substrate were developed. Geometrical parameters, including substrate curvature and conductive layer thickness, along with electrical excitation parameters, were systematically varied to investigate their impact on the sound field up to approximately 1 MHz. The results indicate that, among the parameters studied, substrate curvature exerts the most significant influence on the sound field. T2 - DAS-DAGA Tagung CY - Kopenhagen, Danmark DA - 17.03.2025 KW - Air-coupled ultrasound KW - Thermoacoustic transmitter KW - Focussed transducer PY - 2025 SP - 1 EP - 4 AN - OPUS4-63092 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Strangfeld, Christoph A1 - Ringeloth, David T1 - DZSF - Rrissdetektion Spannbetonschwellen - Statuspräsentation Los C (BAM) N2 - Vorhaben 8082: Spannbetonschwellen sollen mit Hilfe von akustischen Verfahren untersucht und der Zustand abgeleitet werden. Die Ergebnisse von Los C- Arbeitspaket 1 werden dem Deutschen Zentrum für Schienenforschung und Siemens Mobility vorgestellt. T2 - DZSF - Statuspräsentation CY - Dresden, Germany DA - 12.02.2025 KW - Akustische Verfahren KW - Spannbetonschwellen KW - Zerstörungsfreie Prüfung KW - Zustandsermittlung PY - 2025 AN - OPUS4-62545 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Martin, T. A1 - Zimmermann, E. A1 - Klitzsch, N. A1 - Hördt, A. A1 - Huisman, J. A. A1 - Radic, T. A1 - Kruschwitz, Sabine T1 - Round-robin test of SIP laboratory measurements using electrical test networks N2 - This study presents the results of an interlaboratory test designed to evaluate the accuracy of spectral induced polarization (SIP) measurements using controlled electrical test networks. The study, conducted in Germany since 2006, involved 12 research institutes, six different impedance measurement devices and four types of electrical test networks specifically designed to evaluate phase shift errors in SIP measurements. The test networks, with impedances ranging from 100 to 150 kΩ, represent high-impedance samples with different phase characteristics, and pose the measurement challenges typical of such samples, including high contact impedances and parasitic capacitances. Four key findings emerged from the study: (1) Impedance measurements across all devices showed deviations within 1 per cent over a wide frequency range (0.001–1000 Hz); (2) phase errors remained below 1 mrad up to 100 Hz for most devices, but increased at higher frequencies due to parasitic capacitances and electromagnetic coupling effects; (3) lab-specific instruments have lower phase errors than field instruments when used in a laboratory environment, primarily due to the effects of long cables and too low input impedances of the field instruments; and (4) short cables and driven shielding technology effectively minimized parasitic capacitance and improved measurement accuracy. The study highlights the usefulness of test networks in assessing the accuracy of SIP measurements and raises awareness of the various factors influencing the quality of SIP data. KW - Induced polarization KW - Electrical properties KW - Electrical resistivity tomography (ERT) PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631522 DO - https://doi.org/10.1093/gji/ggaf153 SN - 0956-540X VL - 242 IS - 1 SP - 1 EP - 13 PB - Oxford University Press (OUP) AN - OPUS4-63152 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -