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 OPUS4-4232 Vortrag Hille, Falk Long Term Monitoring of Real Structures 2003 SAMCO Summer Academy SAMCO Summer Academy Cambridge, England 2003-07-16 2016-02-19 OPUS4-7334 Beitrag zu einem Tagungsband Rücker, Werner; Said, Samir; Rohrmann, Rolf; Schmid, Wolfgang; Hille, Falk; Mehdianpour, Milad Aufgaben der Dauerüberwachung und baulichen Bewertung am Beispiel von Betonbrücken und Windenergieanlagen Berlin BAM 2005 Fachtagung des Deutschen Ausschusses für Stahlbeton 2005 - Zerstörungsfreie Prüfverfahren und Bauwerksdiagnose im Betonbau Fachtagung 2005 des Deutschen Ausschusses für Stahlbeton "Zerstörungsfreie Prüfverfahren und Bauwerksdiagnose im Betonbau" Berlin, Deutschland 2005-03-10 2005-03-11 A39 A46 2016-02-19 OPUS4-42731 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Stochastic subspace-based damage detection with uncertainty in the reference null space This paper deals with uncertainty considerations in damage diagnosis using the stochastic subspace-based damage detection technique. With this method, a model is estimated from data in a (healthy) reference state and confronted to measurement data from the possibly damaged state in a hypothesis test. Previously, only the uncertainty related to the measurement data was considered in this test, whereas the uncertainty in the estimation of the reference model has not been considered. We derive a new test framework, which takes into account both the uncertainties in the estimation of the reference model as well as the uncertainties related to the measurement data. Perturbation theory is applied to obtain the relevant covariances. In a numerical study the effect of the new computation is shown, when the reference model is estimated with different accuracies, and the performance of the hypothesis tests is evaluated for small damages. Using the derived covariance scheme increases the probability of detection when the reference model estimate is subject to high uncertainty, leading to a more reliable test. 2017 Proceedings of the 11th International Workshop on Structural Health Monitoring 2017: Real-Time State Awareness and Data-Driven Safety Assurance 978-1-60595-330-4 International Workshop on Structural Health Monitoring Stanford, CA, USA 12.09.2017 14.09.2017 1007 1014 2017-11-07 OPUS4-44306 Beitrag zu einem Tagungsband Unger, Jörg F.; Gründer, Klaus-Peter; Hille, Falk; Liehr, Sascha; Maack, Stefan; Niederleithinger, Ernst; Pirskawetz, Stephan; Rogge, Andreas; Said, Samir; Viefhues, Eva; Zorn, Sebastian Baeßler, Matthias; Möller, G.; Rogge, Andreas; Schiefelbein, N. Innovative Messsysteme zum Brückenmonitoring am Beispiel einer Versuchsbrücke - vom Sensor bis zur Zustandsprognose In der aktuellen Projektphase liegt der Fokus auf der Datenaufnahme, -bearbeitung und -speiche-rung mit dem Ziel, automatisierte Auswerteverfahren einsetzen zu können. Aktuell wurden primär punktuelle Messungen an ausgewählten Messtagen aufgenommen. Die Systeme sollen so weiter-entwickelt werden, dass sie sich auch für kontinuierliche Messungen im Rahmen von Monitoring-aufgaben eignen. Ein wichtiger Fokus bei der Auswertung ist die Kombination mit numerischen Modellen, die mithilfe von Bayesian Update Verfahren und den aufgenommenen Messdaten kalibriert und im Verlauf der Monitoringaufgabe angepasst werden sollen. Insbesondere sollen auch zeitabhängige Modelle, die eine zeitliche Entwicklung von Struktureigenschaften beinhalten (Kriechen, Schwinden, Ermüdung, Korrosion) dazu verwendet werden, die zukünftige Performance der Struktur bewerten zu können. Basierend darauf werden dann Konzepte zur Planung von Inspektion und Wartung erstellt. Berlin Bundesanstalt für Materialforschung und -prüfung (BAM) Bundesanstalt für Materialforschung und -prüfung (BAM) 2017 Messen im Bauwesen 2017 2017/1 978-3-9818270-8-8 Messen im Bauwesen 2017 Berlin, Germany 14.11.2017 14.11.2017 7 19 2018-02-27 OPUS4-46059 Beitrag zu einem Tagungsband Baeßler, Matthias; Hille, Falk Powers, N.; Frangopol, D. A study on diverse strategies for discriminating environmental from damage based variations in monitoring data Right from the beginning of applying SHM to bridge structures it was obvious that environmental based perturbations on the measurement significantly influence the ability to identify structural damage. Strategies are needed to classify such effects and consider them appropriately in SHM. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge taking into account environmental as well as damage based changes of stiffness values. With the back-ground of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of procedures, separating environmental from damage caused changes in SHM measures. The contribution describes both general strategies and points out their Advantages and drawbacks. As basis, a review on relevant methods was conducted. The aim of the study is to classify approaches for separating damage describing information from environmental based perturbations in dependency of the SHM objective. And such, it is intended to describe a best practice in designing concepts for Monitoring infrastructure, naturally effected by environmental influences. CRC Press 2018 Maintenance, Safety, Risk, Management and Life-Cycle Performance of Bridges 978-1-138-73045-8 IABMAS Melbourne, Australia 09.07.2018 13.07.2018 1557 1564 2018-09-27 OPUS4-44669 Zeitschriftenartikel Makris, Ruben; Hille, Falk; Thiele, Marc; Kirschberger, D.; Sowietzki, D. Crack luminescence as an innovative method for detection of fatigue damage In structural parts under vibrational loading fatigue cracks can initiate and grow, which can lead to structural failure. Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution, whereas crack luminescence coating realizes clear visibility of the entire crack formation. Fatigue causing cyclic tensile tests and examinations on special test bodies allowing control of the crack opening width demonstrate a high sensitivity of the coating. Göttingen, Germany Copernicus Publications 2018 Journal of Sensors and Sensor Systems 7 259 266 urn:nbn:de:kobv:b43-446693 10.5194/jsss-7-259-2018 https://creativecommons.org/licenses/by/4.0/deed.de 2018-04-11 OPUS4-45127 Buchkapitel Döhler, Michael; Hille, Falk; Mevel, Laurent Ottaviano, Erika; Pelliccio, Assunta; Gattulli, Vincenzo Vibration-based monitoring of civil structures with subspace-based damage detection Automatic vibration-based structural health monitoring has been recognized as a useful alternative or addition to visual inspections or local non-destructive testing performed manually. It is, in particular, suitable for mechanical and aeronautical structures as well as on civil structures, including cultural heritage sites. The main challenge is to provide a robust damage diagnosis from the recorded vibration measurements, for which statistical signal processing methods are required. In this chapter, a damage detection method is presented that compares vibration measurements from the current system to a reference state in a hypothesis test, where data9 related uncertainties are taken into account. The computation of the test statistic on new measurements is straightforward and does not require a separate modal identification. The performance of the method is firstly shown on a steel frame structure in a laboratory experiment. Secondly, the application on real measurements on S101 Bridge is shown during a progressive damage test, where damage was successfully detected for different damage scenarios. 1. Cham Springer International Publishing 2018 Mechatronics for Cultural Heritage and Civil Engineering 978-3-319-68645-5 307 326 10.1007/978-3-319-68646-2 2018-06-11 OPUS4-47001 Beitrag zu einem Tagungsband Kowitz, Astrid; Wu, Cheng-Chieh; Hille, Falk; Helmerich, Rosemarie; Kadoke, Daniel; Gründer, Klaus-Peter; Hauser, S.; Schwarzinger, H. Pastramă, Ş. D.; Constantinescu, D. M. Impact on a micro-reinforced UHPC: Experimental studies versus numerical modeling Within the presented research project, experimental and numerical investigations were performed to develop a thin-shelled, modular, mobile element system made of a micro-reinforced ultra-high-performance ductile concrete (DUCON®). Material parameters were experimentally determined to adapt the material model within the numerical analysis applying the Drucker-Prager relationship. Afterwards, for validation of the numerical models, quasi-static and high-velocity impact tests were performed on plate-like structures. Finally, a suitable geometry of transportable barrier elements will be designed, which provides a maximum of resistance against impact by a minimum of weight and a maximum of mobility. Bucarest, Romania Editura Printech 2018 35th Danubia-Adria Symposium on Advances in Experimental Mechanics, Extended Abstracts 978-606-23-0874-2 35th Danubia-Adria Symposium on Advances in Experimental Mechanics Sinaia, Romania 25.09.2018 28. 09.2018 11 12 2018-12-13 OPUS4-47003 Vortrag Hille, Falk Impact on a micro-reinforced UHPC: experimental studies vs. numerical modeling Within the presented research project, experimental and numerical investigations were performed to develop a thin-shelled, modular, mobile element system made of a micro-reinforced ultra-high-performance ductile concrete (DUCON®). Material parameters were experimentally determined to adapt the material model within the numerical analysis applying the Drucker-Prager relationship. Afterwards, for validation of the numerical models, quasi-static and high-velocity impact tests were performed on plate-like structures. Finally, a suitable geometry of transportable barrier elements will be designed, which provides a maximum of resistance against impact by a minimum of weight and a maximum of mobility. 2018 35th Danubia-Adria Symposium on Advances in Experimental Mechanics Sinaia, Romania 25.09.2018 28.09.2018 2018-12-13 OPUS4-47004 Dissertation Hille, Falk Unterraumbasierte Detektion von Strukturschäden an Jacket-Gründungen von Offshore-Windenergieanlagen Die vorliegende Arbeit beschreibt die Adaption eines globalen, schwingungsbasierten Verfahrens zur frühzeitigen Erkennung von Strukturschäden an Gründungsstrukturen offshore installierter Windenergieanlagen (OWEA). Damit soll es, Betreibern von Offshore-Windparks ermöglicht werden, im Rahmen periodisch durchgeführter messtechnischer Überwachungsmaßnahmen mit einem gegenüber wiederkehrender Inspektionen wesentlich geringen Aufwand auftretende Schäden an der Struktur zuverlässig zu delektieren. Das untersuchte und implementierte Verfahren basiert auf der Methode der stochastischen unterraumbasierten Schadensdetektion. Dabei erfolgt eine statistische Analyse des wiederkehrend messtechnisch aufgenommenen dynamischen Antwortverhaltens des mechanischen Systems. Mittels statistischem Test werden signifikante Änderungen in dessen Eigenstruktur und damit Schäden delektiert. Im Rahmen der vorliegenden Arbeit wurden umfangreiche experimentelle als auch numerische Untersuchungen zur Sensitivität und Robustheit des beschriebenen Schadensindikators durchgeführt. Dazu sind zunächst an einem Labormodell mittels künstlich und reversibel eingebrachter Schäden grundlegende Analysen zu den Einflüssen signal- und verfahrensinhärenter Kenngrößen durchgeführt worden. Auf der Basis dieser Ergebnisse wurde im Anschluss mittels numerischer Analysen das Antwortverhalten von OWEA simuliert und der entwickelte Algorithmus zur Schadensdetektion an den so realisierten Datensätzen angewendet. Anhand der Ergebnisse der Arbeit wird aufgezeigt, dass, vorausgesetzt die Windenergieanlage befindet sich in Parkposition, eine Detektion von schon geringen Schäden an Gründungs-strukturen mit dem beschriebenen Verfahren, auch unter Einsatz weniger Messaufnehmer, zuverlässig möglich ist. Berlin Technische Universität 2018 1 219 urn:nbn:de:kobv:b43-470040 10.14279/depositonce-7567 https://creativecommons.org/licenses/by/4.0/deed.de 2018-12-13 OPUS4-47006 Vortrag Hille, Falk Unterraumbasierte Detektion von Strukturschäden an Jacket-Gründungen von Offshore-Windenergieanlagen Die vorliegende Arbeit beschreibt die Adaption eines globalen, schwingungsbasierten Verfahrens zur frühzeitigen Erkennung von Strukturschäden an Gründungsstrukturen offshore installierter Windenergieanlagen (OWEA). Damit soll es, Betreibern von Offshore-Windparks ermöglicht werden, im Rahmen periodisch durchgeführter messtechnischer Überwachungsmaßnahmen mit einem gegenüber wiederkehrender Inspektionen wesentlich geringen Aufwand auftretende Schäden an der Struktur zuverlässig zu delektieren. Das untersuchte und implementierte Verfahren basiert auf der Methode der stochastischen unterraumbasierten Schadensdetektion. Dabei erfolgt eine statistische Analyse des wiederkehrend messtechnisch aufgenommenen dynamischen Antwortverhaltens des mechanischen Systems. Mittels statistischem Test werden signifikante Änderungen in dessen Eigenstruktur und damit Schäden delektiert. Im Rahmen der vorliegenden Arbeit wurden umfangreiche experimentelle als auch numerische Untersuchungen zur Sensitivität und Robustheit des beschriebenen Schadensindikators durchgeführt. Dazu sind zunächst an einem Labormodell mittels künstlich und reversibel eingebrachter Schäden grundlegende Analysen zu den Einflüssen signal- und verfahrensinhärenter Kenngrößen durchgeführt worden. Auf der Basis dieser Ergebnisse wurde im Anschluss mittels numerischer Analysen das Antwortverhalten von OWEA simuliert und der entwickelte Algorithmus zur Schadensdetektion an den so realisierten Datensätzen angewendet. Anhand der Ergebnisse der Arbeit wird aufgezeigt, dass, vorausgesetzt die Windenergieanlage befindet sich in Parkposition, eine Detektion von schon geringen Schäden an Gründungs-strukturen mit dem beschriebenen Verfahren, auch unter Einsatz weniger Messaufnehmer, zuverlässig möglich ist. 2018 Wissenschaftliche Aussprache Berlin, Germany 19.10.2018 19.10.2018 2018-12-13 OPUS4-47009 Vortrag Hille, Falk Risslumineszenz Präsentation zur Entwicklung einer Spezialbeschichtung zur Detektion und Überwachung von Ermüdungsrissen. 2018 BAST Ausschusssitzung der Bund-/Länderarbeitsgruppe AG 2.5 - Korrosionsschutz für Stahlbauten im Bereich der Bundesfernstraßen Hamburg, Germany 02.03.2018 02.03.2018 2018-12-17 OPUS4-40489 Beitrag zu einem Tagungsband Bhuyan, M.D.; Viefhues, Eva; Döhler, M.; Lecieux, Y.; Mevel, L.; Hille, Falk; Schoefs, F. Output-only Subspace and Transfer Matrix-based Damage Localization and Quantification This paper deals with vibration-based damage localization and quantification from output-only measurements. We describe an approach which operates on a data-driven residual vector that is statistically evaluated using information from a finite element model, without updating the parameters of the model. First, the damaged elements are detected in statistical tests, and second, the damage is quantified only for the damaged elements. We propose a new residual vector in this context that is based on the transfer matrix difference between reference and damaged states, and compare it with a previously introduced subspace-based residual. We show localization and quantification on both residuals in simulations. 2017 Proceedings of 7th International Operational Modal Analysis Conference 978-3-8440-5247-3 7th International Operational Modal Analysis Conference Ingolstadt, Germany 10.05.2017 12.05.2017 278 288 2017-06-12 OPUS4-46303 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Simani, S.; Patan, K. Asymptotic analysis of subspace-based data-driven residual for fault detection with uncertain reference The local asymptotic approach is promising for vibration-based fault diagnosis when associated to a subspace-based residual function and efficient hypothesis testing tools. It has the ability of detecting small changes in some chosen system parameters. In the residual function,the left null space of the observability matrix associated to a reference model is confronted to the Hankel matrix of output covariances estimated from test data. When this left null space is not perfectly known from a model, it should be replaced by an estimate from data to avoid model errors in the residual computation. In this paper, the asymptotic distribution of the resulting data-driven residual is analyzed and its covariance is estimated, which includes also the covariance related to the reference null space estimate. The advantages of the data-driven residual are demonstrated in a numerical study, and the importance of including the covariance of the reference null space estimate is shown, which increases the detection Performance. Elsevier International Federation of Automatic Control 2018 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2018 51 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes SAFEPROCESS 2018 Warsaw, Poland 29.08.2018 31.08.2018 24 414 419 10.1016/j.ifacol.2018.09.610 2018-10-17 OPUS4-48637 Posterpräsentation Moosavi, Robabeh; Grunwald, Marcel; Redmer, Bernhard; Nerger, Deborah; Hille, Falk; Kühn, T.; Hering, M. Damage investigations of concrete under impact load using laminography We examine the behavior of reinforced concrete components subjected to impact induced loading conditions which might be caused by vessels collisions such as aircraft fuel tanks The concrete plates were impact damaged at TU Dresden and shipped to BAM At BAM laminar tomography as the imaging method is used to determine and quantify the damage state An automatic crack detection method based on template matching is applied to find the cracks and we aim to develop a new method using machine learning Algorithms In addition numerical models are developed to understand the experiment and to predict the damage structures based on failure mechanisms. 2018 DCMS Summer School MATERIALS 4.0 Dresden, Germany 10.09.2018 14.09.2018 2019-08-06 OPUS4-48243 Beitrag zu einem Tagungsband Bhuyan, Md Delwar Hossain; Döhler, M.; Lecieux, Y.; Lupi, C.; Thomas, J.; Schoefs, F.; Hille, Falk; Mevel, L. Statistical Subspace-based Damage Localization on Saint-Nazaire Bridge Mock-Up The subject of damage localization is an important issue for Structural Health Monitoring (SHM) particularly in mechanical or civil structures under ambient excitation. In this paper, the statistical subspacebased damage localization method has been applied on a benchmark application, namely a 1/200 scale model of the Saint-Nazaire Bridge, which is a cable-stayed bridge located on the Loire River near the river's mouth. The employed damage localization method combines data-driven features with physical parameter information from a finite element model in statistical tests, avoiding typical ill-conditioning problems of FE model updating. Damage is introduced in the mockup for cable failures on some of the 72 cables. The purpose of the experiment is to assess the capability of damage assessment methods to find a cable failure. 2019 Proceedings of 8th International Operational Modal Analysis Conference International Operational Modal Analysis Conference Copenhagen, Danmark 13.05.2019 15.05.2019 1 9 2019-06-20 OPUS4-48843 Zeitschriftenartikel Bhuyan, Md Delwar Hossain; Gautier, G.; Le Touz, N.; Döhler, M.; Hille, Falk; Dumoulin, J.; Mevel, L. Vibration-based damage localization with load vectors under temperature changes Damage detection and localization in civil or mechanical structures is a subject of active development and research. A few vibration-based methods have been developed so far, requiring, for example, modal parameter estimates in the reference and damaged states of the investigated structure, and for localization in addition a finite element model. For structures in operation, temperature has been shown to be a major nuisance to the efficiency of such methods because the modal parameters are varying not only with damage but also due to temperature variations. For detection, a few rejection approaches have been developed. Besides the increased complexity, environmental variation is hardly taken into account in localization approaches. In this paper, we propose a sensitivity-based correction of the identified modal parameters in the damaged state with respect to the temperature field in the reference state, on the basis of a sensitivity analysis with respect to temperature dependent Parameters of the finite element model in the reference state. The approach is then applied to the stochastic dynamic damage locating vector method, where its improved performance under nonuniform temperature variations is shown in a numerical application on a beam. John Wiley & Sons, Ltd. 2019 Structural Control and Health Monitoring e2439, 1 16 10.1002/stc.2439 2019-09-04 OPUS4-49167 Beitrag zu einem Tagungsband Baeßler, Matthias; Bhuyan, Delwar; Hille, Falk; Viefhues, Eva; Döhler, M.; Mevel, L. Zingoni, Alphose Impact of environmental based effects on SHM strategies Environmental based perturbations influence significantly the ability to identify structural dam-age in Structural Health Monitoring. Strategies are needed to classify such effects and consider them appropri-ately in SHM. It has to be considered if seasonal effects just mask the structural response or if temperature itself correlates to a weakening of the structure. Various methods have been developed and analyzed to separate environmental based effects from damage induced changes in the measures. Generally, two main approaches have emerged from research activity in this fields: (a) statistics-based tools analyzing patterns in the data or in computed parameters and (b) methods, utilizing the structural model of the bridge considering environmental as well as damage-based changes of stiffness values. With the background of increasing affordability of sensing and computing technology, effort should be made to increase sensitivity, reliability and robustness of proce-dures, separating environmental from damage caused changes in SHM measures. The contribution describes an attempt to evaluate both general strategies, their advantages and drawbacks. In addition, two vibration moni-toring procedures are introduced, allowing for temperature-based perturbations of the monitoring data. Boca Raton CRC Press Department of Civil Engineering, University of Cape Town 2019 Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications 978-1-138-38696-9 SEMC 2019 Cape Town, South Africa 02.09.2019 04.09.2019 Paper 324, 1 Paper 324, 6 10.1201/9780429426506 2019-10-01 OPUS4-48943 Beitrag zu einem Tagungsband Thiele, Marc; Hille, Falk; Makris, Ruben Helmerich, Rosemarie; Ilki, A.; Motavalli, M. Comparison of fatigue crack detection methods for high-cyclic loaded steel structures At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety. Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge. For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required. This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures. 2019 Proceedings of SMAR 2019 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures Potsdam, Germany 27.08.2019 29.08.2019 Th.2.A.1-1 Th.2.A.1-8 urn:nbn:de:kobv:b43-489433 https://creativecommons.org/licenses/by/4.0/deed.de 2019-09-16 OPUS4-51769 Beitrag zu einem Tagungsband Nerger, Deborah; Moosavi, Robabeh; Bracklow, F.; Hering, M.; Kühn, T.; Curbach, M.; Hille, Falk; Rogge, Andreas Papadrakakis, M.; Fragiadakis, M.; Papadimitriou, C. Impact damage characterization at RC plates with planar tomography and FEM Prediction of dynamic effects of reinforced concrete structures under impact loading is a technical challenge. This is a consequence of the great variability of the physical properties resulting from the wide adaptability of reinforced concrete and a consequence of the wide range of impact loading. Experiments and numerical investigations are normally used on a small scale to address the problem. In this paper, impact tests on reinforced conrete plates with the lateral dimensions of 1.5 m x 1.5 m and a thickness of 30 cm are presented. In bending reinforcement, besides the velocity two properties are varied, the diameter and the spatial distribution of the rebars. Experiments are performed at the Otto-Mohr-Laboratory of the Institute of Concrete Structures of the Technische Universit¨at Dresden. Due to the accelerated fall of the impactor the velocity ranges between 20 and 70 m/s. In addition to the measured quantities such as bearing forces, accelerations are also measured at 4 different positions on and under the plate, as well as the deflection at several positions. The measured data are used for the analysis of the damage form and the numerical examinations with the program Ansys Autodyn and the material model after Drucker-Prager. Numerical investigations support the tests, with detailed analysis of individual effects. These numerical computations and the planar tomographic investigations were carried out at BAM in Berlin. With the help of planar tomographic evaluation, the damaged structure is made visible and compared with the numerical results. Influences of the bending reinforcement are explained on the basis of damage evaluation in the local area and on selected measured values. In addition to the test evaluation, the tomographic and numerical methods are presented. Athens, Greece Institute of Structural Analysis and Antiseismic Research, School of Civil Engineering, National Technical University of Athens (NTUA), Greece 2020 Proceedings of the XI International Conference on Structural Dynamics (EURODYN 2020) 1 978-618-85072-2-7 XI International Conference on Structural Dynamics (EURODYN 2020) Online meeting 23.11.2020 26.11.2020 2521 2543 2020-12-07 OPUS4-51592 Beitrag zu einem Tagungsband Herrmann, Ralf; Hille, Falk; Said, Samir; Sterthaus, Jens; Müller, Karsten; Quercetti, Thomas; Wille, Frank; Paffenholz, J.-A.; Baeßler, Matthias Papadrakakis, M.; Fragiadakis, M.; Papadimitriou, C. Implementing a Structural Health Monitoring system using digital models of the BAM large drop test facility in Horstwalde At the Bundesanstalt für Materialforschung und -prüfung (BAM) full scale specimens for nuclear transport and storage containers (casks) are tested for their structural integrity in a series of drop tests on the Test Site Technical Safety in Horstwalde, 50 km south of Berlin. These drop tests cause a major stress not only on the casks, but also on the steel tower structure of the test facility, itself. The load pattern makes the structure very interesting for detailed investigation. The focus of the monitoring lies on the bolted joints of the flange connections that are a typical connection for cylindrical elements if welding is technical or economical unfavorable. The definition of the monitoring takes was done by investigating the existing documents and inspection results accompanied by building an initial digital representation of the structure, consisting of two finite element (FE) models and a geometrical 3D point cloud representation. As a first step the structures behavior during static and dynamic loading was analyzed using measurement data and an updated numerical FE Model. The idea behind is to use models for a digital planning and operation/evaluation of the structural health monitoring. A static FE simulation and a dynamic FE simulation are generated, to investigate how the structure behaves under the load conditions. Athen Institute of Structural Analysis and Antiseismic Research National Technical University of Athens (NTUA) 2020 Proceedings of the XI International Conference on Structural Dynamics (EuroDyn 2020) 1 978-618-85072-0-3 XI International Conference on Structural Dynamics (EuroDyn 2020) Online meeting 23.11.2020 26.11.2020 1293 1304 2020-11-30 OPUS4-51617 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Fault detection for linear parameter varying systems under changes in the process noise covariance Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models -- each estimated from data measured in a reference state -- are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. 2020 Preprints of the 21st IFAC World Congress (Virtual) IFAC World Congress 2020 Online meeting 11.07.2020 17.07.2020 13858 2020-11-23 OPUS4-52957 Beitrag zu einem Tagungsband Liao, Chun-Man; Hille, Falk; Fontoura Barroso, Daniel; Niederleithinger, Ernst Papadrakakis, M.; Fragiadakis, M. Monitoring of a prestressed bridge model byultrasonic measurement and vibration recordings The aim of this work is to improve the current structural health monitoring (SHM) methods for civil structures. A field experiment was carried out on a two-span bridge with a built-in un-bonded prestressing system. The bridge is a 24-metre long concrete beam resting on three bear-ings. Cracks were formed subsequently when a prestressing force of 350 kN was changed to 200 kN, so that different structural states could be demonstrated. The structural assessment of this reference bridge was accomplished by the non-destructive testing using ultrasonic devices and vibration measurements. The ultrasonic velocity variations were investigated by using the coda wave interferometry method. The seismic interferometry technique was applied to the vi-bration recordings to reconstruct the wave propagation field in the bridge. This investigation shows that the wave velocity is sensitive to the current structural state and can be considered as the damage indicator. Overall, the implementation of coda cave interferometry and seismic interferometry technique facilitates structural health monitoring (SHM) in civil engineering. European Community on Computational Methods in Applied Sciences (ECCOMAS) 2021 COMPDYN 2021 8th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering COMPDYN 2021 8th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering Online meeting 28.06.2021 30.06.2021 1 9 2021-07-14 OPUS4-52810 Beitrag zu einem Tagungsband Herrmann, Ralf; Schneider, Ronald; Simon, Patrick; Hille, Falk; Said, Samir; Baeßler, Matthias Curbach, M.; Marx, S.; Scheerer, S.; Hampel, T. Structural Health Monitoring der Maintalbrücke Gemünden zur Unterstützung einer prädiktiven Instandhaltung Nach den bisherigen Regeln werden Bauwerksprüfungen von Brücken in starr definierten Intervallen durchgeführt. Diese starre, periodische, zustandsbasierte Instandhaltungsstrategie soll zukünftig durch eine flexible und prädiktive Instandhaltung ersetzt werden. Hierbei sollen Inspektionen und Instandhaltungsmaßnahmen unterstützt durch autonome Systeme auf der Grundlage von Monitoringdaten geplant und zusätzlich bei unvorhergesehenen Ereignissen ausgelöst werden. Im Rahmen des Verbundforschungsvorhabens AISTEC wird ein Vorgehen für Großbauwerke und kleinere Regelbauwerke zur Umsetzung eines kombinierten globalen, schwingungsbasierten und quasistatischen Monitorings entworfen. An der Maintalbrücke Gemünden - einer semiintegralen Rahmenbrücke aus Spannbeton auf der Schnellfahrstrecke Hannover-Würzburg - wurde als Demonstrator ein Dauermonitoring realisiert. Dresden Technische Universität Dresden 2021 Schriftenreihe Konstruktiver Ingenieurbau Dresden 55 11. Symposium Experimentelle Untersuchungen von Baukonstruktionen (SEUB) Online meeting 08.03.2021 66 76 2021-06-14 OPUS4-52465 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Fault detection for linear parameter varying systems under changes in the process noise covariance Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models - each estimated from data measured in a reference state - are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system. Elsevier 2020 IFAC-PapersOnLine: 21st IFAC World Congress 53 21st IFAC World Congress Online meeting 13.07.2020 2 13668 13673 urn:nbn:de:kobv:b43-524652 10.1016/j.ifacol.2020.12.868 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2021-04-21 OPUS4-52998 Zeitschriftenartikel Viefhues, Eva; Döhler, M.; Hille, Falk; Mevel, L. Statistical subspace-based damage detection with estimated reference The statistical subspace-based damage detection technique has shown promising theoretical and practical results for vibration-based structural health monitoring. It evaluates a subspacebased residual function with efficient hypothesis testing tools, and has the ability of detecting small changes in chosen system parameters. In the residual function, a Hankel matrix of Output covariances estimated from test data is confronted to its left null space associated to a reference model. The hypothesis test takes into account the covariance of the residual for decision making. Ideally, the reference model is assumed to be perfectly known without any uncertainty, which is not a realistic assumption. In practice, the left null space is usually estimated from a reference data set to avoid model errors in the residual computation. Then, the associated uncertainties may be non-negligible, in particular when the available reference data is of limited length. In this paper, it is investigated how the statistical distribution of the residual is affected when the reference null space is estimated. The asymptotic residual distribution is derived, where its refined covariance term considers also the uncertainty related to the reference null space estimate. The associated damage detection test closes a theoretical gap for real-world applications and leads to increased robustness of the method in practice. The importance of including the estimation uncertainty of the reference null space is shown in a numerical study and on experimental data of a progressively damaged steel frame. Elsevier Ltd. 2022 Mechanical Systems and Signal Processing 164 108241 10.1016/j.ymssp.2021.108241 2021-07-26 OPUS4-52999 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Simon, Patrick; Herrmann, Ralf; Hille, Falk; Mevel, L. Cunha, A.; Caetano, E. Stochastic subspace-based damage detection of a temperature affected beam structure Structural health monitoring (SHM) of civil structures often is limited due to changing environmental conditions, as those changes affect the structural dynamical properties in a similar way like damages can do. In this article, an approach for damage detection under changing temperatures is presentedand applied to a beam structure. The used stochastic subspace-based algorithm relies on a reference null space estimate, which is confronted to data from the testing state in a residual function. For damage detection the residual is evaluated by means of statistical hypothesis tests. Changes of the system due to temperature effects are handled with a model interpolation approach from linear parameter varying system theory. From vibration data measured in the undamaged state at some few reference temperatures, a model of the dynamic system valid for the current testing temperature is interpolated. The reference null space and the covariance matrix for the hypothesis test is computed from this interpolated model. This approach has been developed recently and was validated in an academic test case on simulations of a mass-spring-damper. In this paper, the approach is validated experimentally on a beam structure under varying temperature conditions in a climate chamber. Compared to other approaches, the interpolation approach leads to significantly less false positive alarms in the reference state when the structure is exposed to different temperatures, while faults can still be detected reliably. 2021 Proceedings of the 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10 10th International Conference on Structural Health Monitoring of Intelligent Infrastructure, SHMII 10 Online meeting 30.06.2021 1 6 2021-07-26 OPUS4-11771 Beitrag zu einem Sammelband Niemann, Joachim; Habel, Wolfgang; Hille, Falk Mencik, J. Complex monitoring system for long-term evaluation of prestressed bridges in the new Lehrter Bahnhof in Berlin Pardubice University of Pardubice 2005 Proceedings of the 2nd International Conference "Reliability, Safety and Diagnostics of Transport Structures and Means 2005" 80-7194-769-5 2nd International conference "Reliability, Safety and Diagnostics of Transport Structures and Means 2005" Pardubice, Czech Republic 2005-07-07 2005-07-08 248 256 2016-02-19 OPUS4-14067 Beitrag zu einem Sammelband Habel, Wolfgang; Niemann, Joachim; Hille, Falk Waßmuth, W. Langzeitmonitoring der äußeren Brücken des Hauptbahnhofs Hamburg Eurailpress Tetzlaff-Hestra 2006 Bahnmetropole Berlin 3-7771-0349-7 116 123 2016-02-19 OPUS4-11680 Beitrag zu einem Sammelband Hille, Falk; Rohrmann, Rolf; Rücker, Werner Parke, G.; Disney, P. Guideline for the assessment of existing structures London Thomas Telford 2005 Bridge management 5 - inspection, maintenance, assessment and repair 0-7277-3354-0 5th International Conference on Bridge Management, "Bridge Management 5, Inspection, maintenance, assessment and repair" Guildford, England, UK 2005-04-11 2005-04-13 227 234 2016-02-19 OPUS4-11566 Beitrag zu einem Sammelband Rücker, Werner; Rohrmann, Rolf; Hille, Falk Guidelines for monitoring and assessment - A SAMCO initiative as a basis for the international standardization London Taylor & Francis 2006 Structural health monitoring and intelligent infrastructure - proceedings of the Second International Conference on Structural Health Monitoring of Intelligent Infrastructure 0-415-39652-2 2nd International Conference on Structural Health Monitoring and Intelligent Infrastructure Shenzhen, China 2005-11-16 2005-11-18 1671 1676 2016-02-19 OPUS4-19483 Beitrag zu einem Tagungsband Mehdianpour, Milad; Herter, Jürgen; Hille, Falk Service life extension of a railway viaduct in Berlin Bridge retrofitting of a section of the Berlin subway which is designed as railway on steel viaduct is presented. Fatigue damage in the superstructure of the over 70-years-old viaduct made an investigation of the damage causes necessary prior to the planning of retrofitting measures. The damage specifically occurred at the inverted arched steel plates of the ballast support elements. Those plates were provided for carrying the track ballast as well as the traffic load. For the retrofitting, the inverted arched plates were unloaded. The superstructure was redesigned into a fixed track system, which is able to transfer the traffic load directly into the substructure. The new rail fastening system made it necessary to verify the structural integrity of single elements as well as of the main system of the existing viaduct. The verification was based on several experimental investigations at BAM laboratory and on-site. Based on the evaluation of all test results the operation license could be issued. Munich, Germany University of the German Armed Forces 2009 Munich Bridge Assessment Conference - MBAC (Proceedings) Munich Bridge Assessment Conference (MBAC 2009) Munich, Germany 2009-05-27 2009-05-29 Paper # T13 1 18 2016-02-19 OPUS4-21271 Beitrag zu einem Tagungsband Herter, Jürgen; Mehdianpour, Milad; Hille, Falk Repair of a railway viaduct in Berlin and inspection concepts to extend the service life Edinburgh, Scotland Engineering Technics Press University of Edinburgh 2010 Structural faults & repair 2010 - International conference and exhibition (Proceedings) 0-947644-67-9 Structural faults & repair 2010 - International conference and exhibition Edinburgh, Scotland, UK 2010-06-15 2010-06-17 1 15 2016-02-19 OPUS4-24579 Vortrag Hille, Falk Subspace-based Damage Detection Methods on a Prestressed Concrete Bridge 2011 EURODYN 2011, "The 8th International Conference on Structural Dynamics" EURODYN 2011, "The 8th International Conference on Structural Dynamics" Leuven, Belgium 2011-07-04 2011-07-06 2016-02-19 OPUS4-24688 Beitrag zu einem Tagungsband Döhler, M.; Hille, Falk; Mevel, L.; Rücker, Werner Chang, F.-K. Structural health monitoring during progressive damage test of S101 bridge For the last decades vibration based identification of damage on civil Engineering structures has become an important issue for maintenance operations on transport infrastructure. Research in that field has been rapidly expanding from classic modal Parameter estimation using measured excitation to modern operational monitoring. Here the difficulty is to regard to the specific environmental and operational influence to the structure under observation. In this paper, two methods accounting for statistical and/or operational uncertainties are applied to measurement data of a progressive damage test on a prestressed concrete bridge. On the base of covariance driven Stochastic Subspace Identification (SSI) an algorithm is developed to monitor and automatically compute confidence intervals of the obtained modal parameters. Furthermore, a null space based non-parametric damage detection method, utilizing a statistical χ2 type test is applied to the measurement data. It can be shown that for concrete bridges the proposed methodology is able to clearly indicate the presence of structural damage, if the damage leads to a change of the structural system. DEStech Publications, Inc. 2011 IWSHM 2011 - 8th International workshop on structural health monitoring 2011 (Proceedings) 1 978-1-60595-053-2 8th International workshop on structural health monitoring 2011 Stanford, CA, USA 13.09.2011 15.09.2011 748 758 2016-02-19 OPUS4-24689 Beitrag zu einem Tagungsband Hille, Falk; Döhler, M.; Mevel, L.; Rücker, Werner De Roeck, G.; Degrande, G.; Lombaert, G.; Müller, G. Subspace-based damage detection methods on a prestressed concrete bridge For the last decades vibration based damage detection of engineering structures has become an important issue for maintenance operations on transport infrastructure. Research in vibration based structural damage detection has been rapidly expanding from classic modal parameter estimation to modern operational monitoring. Methodologies from control Engineering especially of aerospace applications have been adopted and converted for the application on civil structures. Here the difficulty is to regard to the specific environmental and operational influence to the structure under observation. A null space based damage detection algorithm is tested for its sensitivity to structural damage of a prestressed concrete road bridge. Specific techniques and extensions of the algorithm are used to overcome difficulties from the size of the structure which is associated with the number of recorded sensor channels as well as from the operational disturbances by a nearby construction site. It can be shown that for concrete bridges the proposed damage detection methodology is able to clearly indicate the presence of structural damage, if the damage leads to a significant change of the structural system. Small damage which do not result in a System change when not activated by loading, do not lead to a modification of the dynamic response behavior and for that cannot be detected with the proposed global monitoring method. Katholieke Universiteit Leuven 2011 EURODYN 2011 - 8th International conference on structural dynamics (Proceedings) 978-90-760-1931-4 EURODYN 2011 - 8th International conference on structural dynamics Leuven, Belgium 04.07.2011 06.07.2011 MS12 TUE 11:45 2304 2310 2016-02-19 OPUS4-24736 Vortrag Hille, Falk Damage monitoring on OWT structures 2011 BAM-DTU Workshop on Design and maintenance of support structures for Offshore Wind Converters BAM-DTU Workshop on Design and maintenance of support structures for Offshore Wind Converters Copenhagen, Denmark 2011-10-25 2016-02-19 OPUS4-39354 Beitrag zu einem Tagungsband Baeßler, Matthias; Hille, Falk; Said, Samir Baeßler, Matthias; Rogge, Andreas; Möller, Gerd; Schiefelbein, Norbert Bauwerksüberwachung von Brücken im Kontext saisonaler Einflüsse Anhand verschiedener Bespiele wird diskutiert, wie Temperaturbeanspruchungen in einer Bauwerksüberwachung sichtbar werden und wie sie zu bewerten sind. Insbesondere der Einfluss auf die Zustandsbewertung im Sinne der Standsicherheit stellt häufig eine große Schwierigkeit dar. Behelfsweise besteht eine grundlegende Möglichkeit darin, ein Tragwerk immer zu seiner schwächsten Phase, d.h. in der Regel im Sommer zu beurteilen. Wie aufgezeigt, können zudem statistische Verfahren geeignet sein, Tragfähigkeitsänderungen zu detektieren. Als wesentliche Zukunftsaufgaben werden verbesserte Detektionsalgorithmen und physikalisch begründete Modelle zum mechanischen Verhalten angesehen. Die Akzeptanz schwingungsbasierter Verfahren zur Detektion und Lokalisierung von Schäden in der praktischen Anwendung ist alleinig von der Fähigkeit abhängig, Einflüsse aus veränderlichen Umwelt- und Betriebsbedingungen, insbesondere aber die aus der Temperatur zu eliminieren. Da die in den letzten Jahren immer wichtiger werdenden stochastischen Verfahren zur Schadensde-tektion und -lokalisierung die (statistische) Charakteristik der Messdaten bereits implizit nutzen, sind hier Entwicklung, Anpassung und Anwendung statistischer Algorithmen zur Eliminierung der variierenden Umwelteinflüsse naheliegend. Auf der anderen Seite wird der saisonale Einfluss auf Bauwerksmessungen in sehr vielen Veröf-fentlichungen dargestellt und es werden häufig verdachtsweise begründete physikalische Zu-sammenhänge für das Verhalten aufgezeigt. Im Regelfall sind die Aussagen aber nicht experi-mentell überprüft und von eher allgemeiner Natur („Asphalt reagiert temperaturabhängig"). Ob-jektspezifische Zusammenhänge, beispielsweise über Versuch an Repräsentanten in der Klima-kammer ermittelt, könnten jedoch sehr hilfreich sein. Eigenverlag BAM 2016 Tagungsband "Messen im Bauwesen 2016" 2016 978-3-9817853-6-4 Messen Im Bauwesen BAM, Berlin, Germany 08.11.2016 89 102 2017-03-14 OPUS4-24335 Beitrag zu einem Tagungsband Döhler, M.; Hille, Falk; Lam, X.-B.; Mevel, L.; Rücker, Werner Proulx, T. Confidence intervals of modal parameters during progressive damage test In Operational Modal Analysis, the modal parameters (natural frequencies, damping ratios and mode shapes) obtained from Stochastic Subspace Identification (SSI) of a structure, are afflicted with statistical uncertainty. For evaluating the quality of the obtained results it is essential to know the respective confidence intervals of these figures. In this paper we present algorithms that automatically compute the confidence intervals of modal parameters obtained from covarianceand data-driven SSI of a structure based on vibration measurements. They are applied to the monitoring of the modal parameters of a prestressed concrete highway bridge during a progressive damage test that was accomplished within the European research project IRIS. Results of the covariance- and data-driven SSI are compared. Springer The society for experimental mechanics 2011 29th IMAC - Conference on structural dynamics (Proceedings) 4 978-1-4419-9304-5 29th IMAC - Conference on structural dynamics Jacksonville, FL, USA 31.01.2011 03.02.2011 237 250 10.1007/978-1-4419-9305-2_17 2016-02-19 OPUS4-19958 Beitrag zu einem Tagungsband Mehdianpour, Milad; Herter, Jürgen; Hille, Falk Steffen Marx, ; Heinz Opitz, ; Manfred Curbach, Experimentelle Ermittlung des Lastabtrages von Bremskräften an einem Stahlviadukt der Berliner U-Bahn Technische Universität Dresden - Fakultät Bauingenieurwesen 2009 5. Symposium "Experimentelle Untersuchungen von Baukonstruktionen" 5. Symposium "Experimentelle Untersuchungen von Baukonstruktionen" Dresden, Deutschland 2009-09-11 2009-09-11 18 183 196 2016-02-19 OPUS4-18141 Vortrag Hille, Falk Stochastische, subspace-basierte, kovarianz-gesteuerte output-only Identifikation von Schädigungen 2008 TU Berlin, Institut für Statik und Dynamik TU Berlin, Institut für Statik und Dynamik Berlin, Germany 2008-10-22 2016-02-19 OPUS4-20495 Vortrag Thöns, Sebastian; Hille, Falk Damage detection and risk estimation of bridge S101 2009 IRIS Summer Academy IRIS Summer Academy Zell am See, Austria 2009-04-01 2009-04-04 2016-02-19 OPUS4-29758 Vortrag Hille, Falk State of the Art in Monitoring and Assessment of Structures 2013 IRIS-NERA Summer Academy 2013 IRIS-NERA Summer Academy 2013 Zell am See, Austria 2013-09-02 2013-09-03 2016-02-20 OPUS4-29899 Zeitschriftenartikel Döhler, Michael; Mevel, L.; Hille, Falk Subspace-based damage detection under changes in the ambient excitation statistics In the last ten years, monitoring the integrity of the civil infrastructure has been an active research topic, including in connected areas as automatic control. It is common practice to perform damage detection by detecting changes in the modal parameters between a reference state and the current (possibly damaged) state from measured vibration data. Subspace methods enjoy some popularity in structural engineering, where large model orders have to be considered. In the context of detecting changes in the structural properties and the modal parameters linked to them, a subspace-based fault detection residual has been recently proposed and applied successfully, where the estimation of the modal parameters in the possibly damaged state is avoided. However, most works assume that the unmeasured ambient excitation properties during measurements of the structure in the reference and possibly damaged condition stay constant, which is hardly satisfied by any application. This paper addresses the problem of robustness of such fault detection methods. It is explained why current algorithms from literature fail when the excitation covariance changes and how they can be modified. Then, an efficient and fast subspace-based damage detection test is derived that is robust to changes in the excitation covariance but also to numerical instabilities that can arise easily in the computations. Three numerical applications show the efficiency of the new approach to better detect and separate different levels of damage even using a relatively low sample length. London Elsevier Ltd. 2014 Mechanical systems and signal processing 45 1 207 224 10.1016/j.ymssp.2013.10.023 2016-02-20 OPUS4-29906 Buchkapitel Döhler, Michael; Hille, Falk; Mevel, L.; Rücker, Werner Estimation of modal parameters and their uncertainty bounds from subspace-based system identification Vienna, Austria Vienna consulting engineers ZT GmbH 2013 IRIS Industrial safety and life cycle engineering - Technologies / Standards / Applications 978-3-200-03179-1 Chapter 5 91 106 2016-02-20 OPUS4-28070 Beitrag zu einem Tagungsband Hille, Falk; Said, Samir; Schmid, Wolfgang Lasteinwirkung- und Zustandsüberwachung von großen Spannbetonbrücken Die dauerhafte messtechnische Überwachung von Brückenbauwerken ist nach wie vor eine neuartige Verfahrensweise zur Bestimmung des Ist-Zustandes von Tragwerken. Der Fachbereich 7.2 Ingenieurbau der BAM befasst sich seit mittlerweise mehr als 25 Jahren mit der Entwicklung von Methoden und Verfahren dieser Form der Bauwerksüberwachung. Die damit verbundene Tätigkeit umfasst die Beschreibung theoretischer Grundlagen, die Entwicklung von Algorithmen zur Erfassung, Bearbeitung und Auswertung von Messsignalen, die Bewertung der Ergebnisse bezüglich Tragsicherheit, Gebrauchstauglichkeit und Restnutzungsdauer und nicht zuletzt die Untersuchung und Verifizierung der praktischen Anwendbarkeit. Dabei standen insbesondere die sogenannten dynamischen Verfahren im Blickpunkt der Aktivitäten. Ursprünglich zur Überwachung von rotierenden Maschinenkomponenten entwickelt und dann auch erfolgreich zur Überwachung von Bauteilen der Flugzeug-, Raumfahrt- und Automobilindustrie weiterentwickelt, weckten diese Verfahren weltweit das Interesse der sich mit der Sicherheit bestehender Baukonstruktionen befassenden Wissenschaftler und Ingenieure. Ein beachtenswertes Projekt der BAM in diesem Zusammenhang ist die Dauerüberwachung der Westendbrücke in Berlin, das Mitte der 90er Jahre von der damaligen Senatsverwaltung für Stadtentwicklung von Berlin (ehemals Bauen, Wohnen und Verkehr) in Auftrag gegeben und über viele Jahre gefördert wurde. Im Rahmen dieses Aufsatzes werden am Beispiel dieses Projektes, das sich wie ein roter Faden durch die Entwicklungsgeschichte des Monitorings an der BAM zieht, die Motivationen und Zielstellungen dargelegt, das Überwachungssystem vorgestellt und die gemachten Erfahrungen anhand einiger Ergebnisse erläutert. In einem weiteren Kapitel wird ein Ausblick auf die Zukunft des Monitorings mit angepassten Zielvorstellungen, neuen Methodiken und Strategien geworfen. Bundesanstalt für Materialforschung und -prüfung (BAM) 2013 Messen im Bauwesen 2013 - Ingenieuraufgaben und messtechnische Lösungen 978-3-9815360-5-8 Messen im Bauwesen 2013 - Ingenieuraufgaben und messtechnische Lösungen Berlin, Germany 12.03.2013 12.03.2013 107 119 2016-02-20 OPUS4-28026 Vortrag Hille, Falk Lasteinwirkungs- und Zustandsüberwachung von großen Spannbetonbrücken 2013 Messen im Bauwesen 2013 Messen im Bauwesen 2013 Berlin, Germany 2013-03-12 2013-03-12 2016-02-20 OPUS4-30665 Zeitschriftenartikel Döhler, Michael; Hille, Falk; Mevel, L.; Rücker, Werner Structural health monitoring with statistical methods during progressive damage test of S101 Bridge For the last decades vibration based damage detection of engineering structures has become an important issue for maintenance operations on transport infrastructure. Research in vibration based structural damage detection has been rapidly expanding from classic modal parameter estimation to modern operational monitoring. Since structures are subject to unknown ambient excitation in operation conditions, all estimates from the finite data measurements are of statistical nature. The intrinsic uncertainty due to finite data length, colored noise, non-stationary excitations, model order reduction or other operational influences needs to be considered for robust and automated structural health monitoring methods. In this paper, two subspace-based methods are considered that take these statistical uncertainties into account, first modal parameter and their confidence interval estimation for a direct comparison of the structural states, and second a statistical null space based damage detection test that completely avoids the identification step. The performance of both methods is evaluated on a large scale progressive damage test of a prestressed concrete road bridge, the S101 Bridge in Austria. In an on-site test, ambient vibration data of the S101 Bridge was recorded while different damage scenarios were introduced on the bridge as a benchmark for damage identification. It is shown that the proposed damage detection methodology is able to clearly indicate the presence of structural damage, if the damage leads to a change of the structural system. Oxford Elsevier 2014 Engineering structures 69 183 193 10.1016/j.engstruct.2014.03.010 2016-02-20 OPUS4-31218 Beitrag zu einem Tagungsband Hille, Falk; Petryna, Y.; Rücker, Werner Subspace-based detection of fatigue damage on jacket support structures of offshore wind turbines The paper describes the application of the Stochastic Subspace-based Damage Detection (SSDD) method on model structures for an utilization of this approach on offshore wind turbine structures. Aim of the study was therefore to analyze the usability and efficiency of the detection method as well as to determine an optimized set of parameter for realistic damage on support structures of wind energy turbines. Based on results of an experimental fatigue test on a Steel frame laboratory structure a strategy for a numerical verification of the experimentally evolved damage detection was developed, utilizing a time integration approach to simulate the dynamic response. In a second Step the identified modeling and computing methodology is used to numerically investigate the ability to detect damage in real size structural components of offshore wind turbines. Inria 2014 EWSHM 2014 - 7th European workshop on structural health monitoring (Proceedings) EWSHM 2014 - 7th European workshop on structural health monitoring Nantes, France 08.07.2014 11.07.2014 229 236 2016-02-20 OPUS4-31219 Beitrag zu einem Tagungsband Hille, Falk; Petryna, Y.; Rücker, Werner Cunha, A.; Caetano, E.; Ribeiro, P.; Müller, G. Subspace-based detection of fatigue damage on a steel frame laboratory structure for offshore applications Altematively to common modal analysis as tool for detectmg changes between a reference and an actual (possibly damaged) structural state, the subspace-based damage detection method has been developed in recent years and successfully adopted to test application data sets. Characteristic for that method is that instead of analyzing modal parameters, a Statistical test with respect to changes of a dynamic signature of structural response is introduced. Therefor, a Gaussian residual vector is extracted from the subspace of an output only Vibration data covariance matrix within the reference state. The paper describes the application of this damage detection method within a laboratory fatigue test on a Steel frame structure. Aim of the investigation was to analyze the usability and efficiency of the detection method for realistic damage on carrying structures of wind energy turbines. In a second Step, a numerical model of the lab test structure is developed and validated. Thus, a comparable numerical Simulation of the fatigue damage detection was feasible and the accuracy of the Simulation procedure could be verified. The present study describes the first Step in a two-step approach for quantifying and optimizing fundamental characteristics of SHM Systems for offshore wind turbine structures concerning a required number of sensors and their optimal location. 2014 EURODYN 2014 - 9th International conference on structural dynamics (Proceedings) 978-972-752-165-4 EURODYN 2014 - 9th International conference on structural dynamics Porto, Portugal 30.06.2014 02.07.2014 MS25, 3595 3602 2016-02-20 OPUS4-31220 Buchkapitel Döhler, Michael; Hille, Falk Wicks, A. Subspace-based damage detection on steel frame structure under changing excitation Damage detection can be performed by detecting changes in the modal parameters between a reference state and the current (possibly damaged) state of a structure from measured output-only vibration data. Alternatively, a subspace-based damage detection test has been proposed and applied successfully, where changes in the modal parameters are detected, but the estimation of the modal parameters themselves is avoided. Like this, the test can run in an automated way directly on the vibration measurements. However, it was assumed that the unmeasured ambient excitation properties during measurements of the structure in the reference and possibly damaged condition stay constant, which is hardly satisfied by any application. A new version of the test has been derived recently that is robust to such changes in the ambient excitation. In this paper, the robust test is recalled and its performance is evaluated both on numerical simulations and a real application, where a steel frame structure is artificially damaged in the lab. Springer The society for experimental mechanics 2014 Structural health monitoring, Volume 5 - Proceedings of the 32nd IMAC, A conference and exposition on structural dynamics, 2014 5 978-3-319-04569-6 Chapter 19, 167 174 10.1007/978-3-319-04570-2_19 2016-02-20 OPUS4-31232 Vortrag Hille, Falk Subspace-based detection of fatigue damage on a steel frame laboratory structure for offshore applications. 2014 9th International Conference on Structural Dynamics, EURODYN 2014 9th International Conference on Structural Dynamics, EURODYN 2014 Oporto, Portugal 2014-06-30 2014-07-02 2016-02-20 OPUS4-31233 Vortrag Hille, Falk Subspace-based detection of fatigue damage on jacket support structures of offshore wind turbines. 2014 7th European Workshop on Structural Health Monitorin, EWSHM 2014 7th European Workshop on Structural Health Monitorin, EWSHM 2014 Nantes, France 2014-07-08 2014-07-11 2016-02-20 OPUS4-31573 Beitrag zu einem Tagungsband Döhler, Michael; Mevel, L.; Hille, Falk Efficient computation of minmax tests for fault isolation and their application to structural damage localization Fault detection and isolation can be handled by many different approaches. This paper builds upon a hypothesis test that checks whether the mean of a Gaussian random vector has become non-zero in the faulty state, based on a chi2 test. For fault isolation, it has to be decided which components in the parameter set of the Gaussian vector have changed, which is done by variants of the chi2 hypothesis test using the so-called sensitivity and minmax approaches. While only the sensitivity of the tested parameter component is taken into account in the sensitivity approach, the sensitivities of all parameters are used in the minmax approach, leading to better statistical properties at the expense of an increased computational burden. The computation of the respective test variable in the minmax test is cumbersome and may be ill-conditioned especially for large parameter sets, asking hence for a careful numerical evaluation. Furthermore, the fault isolation procedure requires the repetitive calculation of the test variable for each of the parameter components that are tested for a change, which may be a significant computational burden. In this paper, dealing with the minmax problem, we propose a new efficient computation for the test variables, which is based on a simultaneous QR decomposition for all parameters. Based on this scheme, we propose an efficient test computation for a large parameter set, leading to a decrease in the numerical complexity by one order of magnitude in the total number of parameters. Finally, we show how the minmax test is useful for structural damage localization, where an asymptotically Gaussian residual vector is computed from output-only vibration data of a mechanical or a civil structure. IFAC 2014 19th World congress of the international federation of automatic control (Proceedings) 19th World congress of the international federation of automatic control Cape Town, South Africa 24.08.2014 29.08.2014 7382 7387 2016-02-20 OPUS4-32813 Beitrag zu einem Tagungsband Hille, Falk; Petryna, Y. Monitoring und Schadensdetektion an Tragstrukturen von Offshore-Windenergieanlagen Mit dem generellen Ziel, die Anwendbarkeit und Funktionalität des Verfahrens der stochastischen subspace-basierten Schadensdetektion für Strukturen von Offshore-Windenergieanlagen nachzuweisen, wurden experimentelle und numerische Untersuchungen an einer Laborstruktur sowie anschließend numerische Untersuchungen an einer OWEA-Gründungsstruktur durchgeführt. Das zugrundeliegende Verfahren verwendet einen Ansatz, in weder modale Kenngrößen noch andere benutzerdefinierte Eingaben erfordert, nachdem einmalig der Referenzzustand aufgenommen wurde. Dabei werden ausschließlich dem Belastungsprozess inhärente stochastische Anregungen der betrachteten Struktur genutzt. Auf der Basis experimentell erzielter Detektionsergebnisse aus einem Ermüdungsversuch an einer Laborstruktur aus Stahl wurden numerische Modelle und Berechnungsalgorithmen entwickelt und getestet. In einem zweiten Schritt wird diese Analysemethodik auf eine fiktive OWEA-Jacketstruktur realer Größe angewendet. An den simulierten Strukturantworten im Ungeschädigten und geschädigten Zustand wird der Detektionsalgorithmus angewendet, um den Einfluss von Sensorposition und Abtastrate auf die Schadensdetektion festzustellen. Unter Berücksichtigung einzelner vereinfachender Annahmen zeigten die Ergebnisse der Anwendung der vorgestellten Detektionsmethodik an den numerisch erzeugte Antwortdatensätzen eine beachtliche Empfindlichkeit des x2-Testwert basierten Schadensindikators. Obwohl nicht unter allen Umständen in einem frühen Stadium nachweisbar, typische Ermüdungsrisse in Schweißverbindungen von aufgelösten Tragwerken haben ab einer Restbiegesteifigkeit von ca. 80% einen signifikanten und detektierbaren Einfluss auf den Schadensindikator. Künftige Forschungsaktivitäten in diesem Bereich sollten neben der Erkennung von Schäden auch die Lokalisierung und ggf. auch die Quantifizierung zum Ziel haben. Erforderlich dazu ist die Berücksichtigung und Verarbeitung der strukturellen Parameter und ihrer Sensitivitäten im zugrunde liegenden mathematischen Modell. Bundesanstalt für Materialforschung und -prüfung (BAM) 2015 Messen im Bauwesen 2015 - Automatisierte Messdatenverarbeitung 978-3-9816668-5-4 Messen im Bauwesen 2015 - Automatisierte Messdatenverarbeitung Berlin, Germany 03.03.2015 03.03.2015 113 125 2016-02-20 OPUS4-32762 Vortrag Hille, Falk Monitoring und Schadensdetektion an Tragstrukturen von Offshore-Windenergieanlagen 2015 Messen im Bauwesen 2015 Messen im Bauwesen 2015 Berlin, Deutschland 2015-03-03 2015-03-03 2016-02-20 OPUS4-32216 Vortrag Hille, Falk Monitoring und Schadensdetektion an Tragstrukturen von Windenergieanlagen 2014 23. Windenergietage 2014 23. Windenergietage 2014 Potsdam 2014-11-11 2014-11-13 2016-02-20 OPUS4-36621 Beitrag zu einem Tagungsband Nery de Araújo Neto, Gilberto; Hille, Falk; Rogge, Andreas Post-impact assessment of reinforced concrete plate load capacity The modeling and prediction of the behavior of reinforced concrete under impact load is still an engineering challenge. The scientific community has put a lot of effort into the development of this knowledge, especially after the unfortunate events of 09/11 in Manhattan. The main concern is with nuclear power plants and how to design structures that can withstand such extreme situations. An experimental investigation has been carried out to collect fundamental data and to develop a deeper understanding of the effect of impact damage on the load capacity of concrete plates. The paper presents the process on the definition of procedures and the first results of an experimental investigation on the damage and residual load capacity of reinforced concrete plates after impact load. Two types of reinforced concrete plates measuring 1.5 x 1.5 x 0.3 m were subjected to the impact of a flat-nose hard projectile. The two types were casted with the same reinforcement and 80 or 40 MPa concrete. After the impact, the plates go through planar tomography, visual inspection and an ultimate load capacity test. The results showed that the planar tomography can be used for the assessment of internal damage on concrete plates, as long as the number of scans in each direction is more than four. The visual inspection gave a good. The formation of cone cracking after the impact load showed the highest influence on the remaining load capacity of the concrete plates. More plates will be tested to confirm the indications at different damage conditions. 2016 International Concrete Sustainability Conference 2016 International Concrete Sustainability Conference 2016 Washington DC, USA 15.05.2016 18.05.2016 Paper Nery, 1 9 2016-08-16 OPUS4-38205 Vortrag Hille, Falk Bewertung der Lebensdauer von messtechnisch überwachten Offshore-Tragstrukturen Der Vortrag beschreibt einen im FB 7.2 der BAM entwickelten Algorithmus zur zuverlässigkeitsbasierten Bewertung von Offshore-Tragstrukturen durch eine gesamtlebensdauerbasierte Betrachtung auf Grundlage messtechnischer Überwachung. Ziel ist die Optimierung von Betrieb und Instandhaltung von Offshore-Windenergieanlagen (OWEA). Nach Einführung in die Zuverlässigkeit ermüdungsbeanspruchter Jacket-Strukturen sowie der Vorstellung der probalistischen Modellierung des Tragwerks und des Schadens wird die Aktualisierung der Zuverlässigkeit durch Informationen aus der Schadensdetektion erläutert. Am Beispiel einer 2D-Jacketstruktur wird exemplarisch die Vorgehensweise des Verfahrens aufgezeigt. 2016 3. Offshoretage Berlin, Germany 17.03.2016 18.03.2016 2016-11-14 OPUS4-38206 Vortrag Hille, Falk Die Aktivitäten der BAM auf dem Gebiet des Monitorings von Brücken und anderen Strukturen des Ingenieurbaus Im Rahmen der Präsentation werden die Aktivitäten des Fachbereichs 7.2 Ingenieurbau auf dem Gebiet der messtechnischen Überwachung von Bauwerken vorgestellt. Nach einer kurzen Vorstellung der BAM und deren Auftrag, der initiierten Themenfelder und der Abteilung 7 der BAM werden einige der im FB 7.2 durchgeführten Monitoringprojekte anhand von zugrundeliegenden Zielstellungen vorgestellt. Ausführlicher wird auf das Überwachungssystem der Westendbrücke sowie die geplanten Arbeiten am im Rahmen des Themenfelds Infrastruktur genehmigten Projekts BLEIB eingegangen. 2016 DBV-AK Brückenbau Gruppe 1 Monitoring (HAB-BRB-1)´, 1. Sitzung Hannover, Germany 25.05.2016 25.05.2016 2016-11-14 OPUS4-51115 Zeitschriftenartikel Nerger, Deborah; Hille, Falk; Moosavi, Robabeh; Grunwald, Marcel; Redmer, Bernhard; Kühn, T.; Hering, M.; Bracklow, F. Post-impact evaluation at RC plates with planar tomography and FEM Due to the wide range of applications, the easy production and the large field of use, reinforced concrete (RC) is a widespread building material. This variety of applications is reflected in a wide range of physical material properties. Not only therefor it still is a technical challenge to provide all necessary test conditions for experimentally reproducing dynamic effects under impact loading of RC structures. In this paper we present investigations on the thicknesses of RC plates under low and medium high velocity impact loading by a flat-tipped impactor. The planar tomography setup at BAM is used to visualize the impact damage and to characterize the damage features such as cracks, scabbing and spalling. Further, the comparison of tomography results with those of an applied numeric simulation analysis is used to verify the numeric models for future damage prognosis under impact loading. Using the results of both, the tomographic as well as the FE analysis, different damage features were investigated and compared regarding their validity. Crack damage plays a leading part and the significance of summarized crack values as well as their distribution is analyzed. The total damage value but also the determined damage distribution both provide an input for describing damage as a function of the impactor velocity and plate thickness. Elsevier 2020 Materials Today: Proceedings 1 10 10.1016/j.matpr.2020.05.671 2020-08-17 OPUS4-51117 Zeitschriftenartikel Nerger, Deborah; Moosavi, Robabeh; Bracklow, F.; Hering, M.; Kühn, T.; Curbach, M.; Hille, Falk; Rogge, Andreas Planar tomography and numerical analysis for damage characterization of impact loaded RC plates The damage analysis of reinforced concrete (RC) is of high interest for reasons of effective maintenance and structural safe-ty of buildings. The damage structures of RC plates loaded by an impact were investigated, applying X-ray planar tomogra-phy and finite element method (FEM). Planar tomography allows getting three-dimensional information of the RC elements and the damage including crack, spalling and scabbing. The FEM model validated on the tomography data justifies the appli-cation for further predictions of the damage description. In this study, we investigated concrete plates of three different thick-ness subjected to impacts at different low- and medium-velocity, whereby the used impactor had a flat tip, which resulted in small penetrations on the front side and scabbing on the rear side. In order to quantify the damage, the damage volume and its distribution through the plate were computed and the correlations between degree of damage and impact velocity were found out. Wiley 2020 Civil Engineering Design 8 1 19 10.1002/cend.202000017 2020-08-17 OPUS4-51051 Zeitschriftenartikel Hille, Falk; Sowietzki, D.; Makris, R. Luminescence-based early detection of fatigue cracks Classic non-destructive fatigue crack detection methods reveal the state of the fatigue damage evolution at the moment of application, generally not under operational conditions. The here introduced crack luminescence method realizes a clear visibility of the occurred and growing crack in loaded components during operation. Different established experiments show that due to the sensitive coating a crack Formation can be detected even in early stage under the premise the crack reached the surface. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. In case of surface crack occurrence, the luminescent light is clearly noticeable by visual observations and also by standard camera equipment which makes automated crack detection possible as well. It is expected that crack luminescence can increase structural safety as well as reduce costs and time for inspections and preventive maintenance. Amsterdam Elsevier 2020 Materials Today: Proceedings 1 5 urn:nbn:de:kobv:b43-510517 10.1016/j.matpr.2020.02.338 https://creativecommons.org/licenses/by-nc-nd/4.0/deed.de 2020-07-27 OPUS4-49541 Beitrag zu einem Tagungsband Nerger, Deborah; Hille, Falk; Moosavi, Robabeh; Grunwald, Marcel; Redmer, Bernhard; Kühn, T.; Hering, M.; Bracklow, F. Improved tomographic investigation for impact damage characterization Reinforced concrete (RC) is used as structural material in most diverse civil engineering applications. For the variability of its physical properties it is still an engineering challenge to meet all necessary requirements for the prediction of dynamic effects under impact loading. In this paper, investigations are shown within the scope of quantifying and evaluating the damage caused by an impact. The experimental investigations are performed in the field of low- and medium-velocity impact. The chosen flat nose shape results in small penetrations on the top side and scabbing on the bottom side. The plate is scanned with an adapted planar tomographic examination after the impact, and the damage is analysed, afterwards. Cracks and spalling are made visible with a reconstruction. The numerical model validated on the tomographic results justifies the application for further predictions of the damage description. IASMIRT 2019 Proceedings of the International conference on structural mechanics in reactor technology 25th International Conference on Structural Mechanics in Reactor Technology - SMIRT25 Charlotte, NC, USA 04.08.2019 09.08.2019 Paper Div 5 S8, 1 9 2019-11-18 OPUS4-48181 Zeitschriftenartikel Kowitz, Astrid; Wu, Cheng-Chieh; Helmerich, Rosemarie; Hille, Falk; Kadoke, Daniel; Gründer, Klaus-Peter; Hauser, S.; Schwarzinger, H. Bland, S. Impact on a micro-reinforced UHPC: Experimental studies versus numerical modeling Within the presented research project, experimental and numerical investigations were performed to develop a thin-shelled, modular, mobile element system made of a micro-reinforced ultra-high-performance ductile concrete (DUCON®). Material parameters were experimentally determined to adapt the material model within the numerical analysis applying the Drucker-Prager relationship. Afterwards, for validation of the numerical models, quasi-static and high-velocity impact tests were performed on plate-like structures. Finally, a suitable geometry of transportable barrier elements will be designed, which provides a maximum of resistance against impact by a minimum of weight and a maximum of mobility. Amsterdam Elsevier Ltd 2019 Materials Today: Proceedings 12 2 474 483 10.1016/j.matpr.2019.03.152 2019-06-07 OPUS4-48182 Beitrag zu einem Tagungsband Bhuyan, Md Delwar Hossain; Le Touz, N.; Gautier, G.; Döhler, M.; Hille, Falk; Dumoulin, J.; Mevel, L. Load vector based damage localization with rejection of the temperature effect The Stochastic Dynamic Damage Locating Vector (SDDLV) approach is a vibration-based damage localization method based on both a finite element model of a structure and modal parameters estimated from output-only measurements in the damage and reference states. A statistical version of the Approach takes into account the inherent uncertainty due to noisy measurement data. In this paper, the effect of temperature fluctuations on the performance of the method is analyzed in a model-based approach using a finite element model with temperature dependent parameters. Robust damage localization is carried out by rejecting the temperature influence on the identified modal parameters in the damaged state. The algorithm is illustrated on a simulated structure. 2019 Proceedings of IOMAC'19 8. International Operational Modal Analysis Conference Kopenhagen, Denmark 12. Mai 2019 1 10 2019-06-07 OPUS4-48183 Beitrag zu einem Tagungsband Bhuyan, Md Delwar Hossain; Döhler, M.; Lecieux, Y.; Lupi, C.; Thomas, J.-C.; Schoefs, F.; Hille, Falk; Mevel, L. Statistical subspace based damage localization on Saint-Nazaire bridge mock-up The subject of damage localization is an important issue for Structural Health Monitoring (SHM) particularly in mechanical or civil structures under ambient excitation. In this paper, the statistical subspacebased damage localization method has been applied on a benchmark application, namely a 1/200 scale model of the Saint-Nazaire Bridge, which is a cable-stayed bridge located on the Loire River near the river's mouth. The employed damage localization method combines data-driven features with physical parameter information from a finite element model in statistical tests, avoiding typical ill-conditioning problems of FE model updating. Damage is introduced in the mockup for cable failures on some of the 72 cables. The purpose of the experiment is to assess the capability of damage assessment methods to find a cable failure. 2019 Proceedings of IOMAC'19 8. International Operational Modal Analysis Conference Kopenhagen, Denmark 12. Mai 2019 14. Mai 2019 1 9 2019-06-07 OPUS4-48240 Beitrag zu einem Tagungsband Viefhues, Eva; Döhler, M.; Zhang, Q.; Hille, Falk; Mevel, L. Subspace-based Damage Detection with Rejection of the Temperature Effect and Uncertainty in the Reference Temperature variation can be a nuisance that perturbs vibration based structural health monitoring (SHM) approaches for civil engineering structures. In this paper, temperature affected vibration data is evaluated within a stochastic damage detection framework, which relies on a null space based residual. Besides two existing temperature rejection approaches - building a reference state from an averaging method or a piecewise method - a new approach is proposed, using model interpolation. In this approach, a general reference model is obtained from data in the reference state at several known reference temperatures. Then, for a particular tested temperature, a local reference model is derived from the general reference model. Thus, a well fitting reference null space for the formulation of a residual is available when new data is tested for damage detection at an arbitrary temperature. Particular attention is paid to the computation of the residual covariance, taking into account the uncertainty related to the null space matrix estimate. This improves the test performance, contrary to prior methods, for local and global damages, resulting in a higher probability of detection (PoD) for the new interpolation approach compared to previous approaches. 2019 Proceedings of 8th International Operational Modal Analysis Conference International Operational Modal Analysis Conference Copenhagen, Danmark 13.05.2019 15.05.2019 1 11 2019-06-20 OPUS4-48241 Beitrag zu einem Tagungsband Bhuyan, Md Delwar Hossain; Le Touz, N.; Gautier, G.; Döhler, M.; Hille, Falk; Dumoulin, J.; Mevel, L. Load Vector Based Damage Localization with Rejection of the Temperature Effect The Stochastic Dynamic Damage Locating Vector (SDDLV) approach is a vibration-based damage localization method based on both a finite element model of a structure and modal parameters estimated from output-only measurements in the damage and reference states. A statistical version of the Approach takes into account the inherent uncertainty due to noisy measurement data. In this paper, the effect of temperature fluctuations on the performance of the method is analyzed in a model-based approach using a finite element model with temperature dependent parameters. Robust damage localization is carried out by rejecting the temperature influence on the identified modal parameters in the damaged state. The algorithm is illustrated on a simulated structure. 2019 Proceedings of 8th International Operational Modal Analysis Conference International Operational Modal Analysis Conference Copenhagen, Danmark 13.05.2019 15.05.2019 1 10 2019-06-20 OPUS4-55476 Vortrag Hille, Falk Discussion on data evaluation of tomographic and numerical results The contribution discusses the processing and analysis of data generated on two different ways of investigations for impact damage in reinforced concrete structures. Damage investigations are essential to determine type and characteristics of damage and thus the residual capacity. Damage describing data is generated using two different types of investigation, a non-destructive tomographic as well as numerical examination. Subsequently, data of both sources was merged and analysed. Within the research project "Behaviour of structural components during impact load conditions caused by aircraft fuel tank collision" reinforces concrete plates were damaged by impact loading, see Hering (2020). Afterwards the damaged specimens were investigated tomographically as well as numerically using several methods and models. Aim of the presented research work was to specify an objective comparability of numerical data with experimentally determined damage patterns and based on this, to establish a quantitative damage evaluation. 2022 26th International Conference on Structural Mechanics in Reactor Technology Potsdam, Germany 10.07.2022 15.07.2022 2022-08-11 OPUS4-55478 Vortrag Hille, Falk; Herrmann, Ralf Structural Health Monitoring am Großen Fallturm der BAM In diesem Beitrag wird die Structural Health Monitoring Kampagne am Großen Fallturm der BAM vorgestellt. 2022 Seminar "Zerstörungsfreie Prüfung" Online meeting 13.01.2022 2022-08-11 OPUS4-55493 Beitrag zu einem Tagungsband Simon, Patrick; Herrmann, Ralf; Schneider, Ronald; Hille, Falk; Baeßler, Matthias; El-Athman, Rukeia Research Data Management of Structural Health Monitoring Projects and Subsequent Applications of Artificial Intelligence Methods Structural health monitoring (SHM) intends to improve the management of engineering structures. The number of successful SHM projects - especially SHM research projects - is ever growing, yielding added value and more scientific insight into the management of infrastructure asset. With the advent of the data age, the value of accessible data becomes increasingly evident. In SHM, many new data-centric methods are currently being developed at a high pace. A consequent application of research data management (RDM) concepts in SHM projects enables a systematic management of raw and processed data, and thus facilitates the development and application of artificial intelligence (AI) and machine learning (ML) methods to the SHM data. In this contribution, a case study based on an institutional RDM framework is presented. Data and metadata from monitoring the structural health of the Maintalbrücke Gemünden for a period of 16 months are managed with the RDM system BAM Data Store, which makes use of the openBIS data management software. An ML procedure is used to classify the data. Feature engineering, feature training and resulting data are performed and modelled in the RDM system. Boca Raton CRC Press 2022 Bridge safety, maintenance, management, life-cycle, resilience and sustainability - Proceedings of the eleventh International Conference on Bridge Maintenance, Safety and Management (IABMAS 2022), Barcelona, Spain, July 11-15, 2022 978-1-032-35623-5 11th International Conference on Bridge Maintenance, Safety and Management (IABMAS2022) Barcelona, Spain 11.07.2022 15.07.2022 1061 1068 10.1201/9781003322641-127 2022-08-16 OPUS4-55513 Zeitschriftenartikel Pirskawetz, Stephan; Steinbock, O.; Hille, Falk; Schmidt, S.; Hofmann, Detlef Erfahrungen aus dem Rückbau der Brücke am Altstädter Bahnhof in der Stadt Brandenburg - Teil 2: Schadensmonitoring bei zerstörenden Versuchen Im Dezember 2019 wurden bei einer turnusmäßigen Inspektion der B 1-Brücke am Altstädter Bahnhof in Brandenburg an der Havel massive und schnell voranschreitende Schäden festgestellt. Als Ursache für die Risse entlang der Längsträger wurde das Versagen eines signifikanten Anteils der Spanndrähte der konzentrierten Spannglieder vermutet. Die Brücke wurde umgehend für den Verkehr gesperrt und im Mai 2021 gesprengt. Im Vorfeld der Sprengung wurden durch das Bundesministerium für Digitales und Verkehr (BMDV) weiterführende Untersuchungen zum Schadensbild veranlasst, welche vom Landesbetrieb Straßenwesen Brandenburg koordiniert und in den Bauablauf integriert wurden. Das von der Hochschule für Technik und Wirtschaft (HTW) Dresden erstellte Versuchskonzept ist Bestandteil des vorangestellten ersten Teils des Beitrags [1]. Hier im zweiten Teil werden ausgewählte Ergebnisse der umfangreichen versuchsbegleitenden Mess- und Monitoringmaßnahmen beschrieben, welche in Kooperation der HTW Dresden, der Bilfinger Noell GmbH sowie der Bundesanstalt für Materialforschung und -prüfung (BAM) durchgeführt wurden. Berlin Ernst & Sohn 2022 Beton- und Stahlbetonbau 117 8 581 589 10.1002/best.202200052 2022-08-16 OPUS4-55627 Beitrag zu einem Tagungsband Niederleithinger, Ernst; Hille, Falk; Hofmann, Detlev; Kind, Thomas Isecke, B.; Krieger, J. Überwachung der Brücke Altstädter Bahnhof, Brandenburg./H. Begleituntersuchungen mit moderner Sensorik und zerstörungsfreier Prüfung Die B1 Brücke am Altstädter Bahnhof in Brandenburg an der Havel wurde im Dezember 2019 aufgrund von während einer turnusmäßigen Inspektion entdeckten Rissen und Hohlstellen entlang der vorgespannten Längsträger gesperrt und im Mai 2021 abgebrochen. In der Zwischenzeit wurde die Brücke detailliert überwacht. Vor dem Abriss wurden zudem umfangreiche Untersuchungen zur Bestandsaufnahme und Schadensanalyse sowie Tests moderner Sensorik vorgenommen. Dabei konnte sowohl die richtige, zuvor nicht sicher bekannte Anzahl von Spanngliedern in den Querträgern sicher ermittelt werden als auch durch moderne Varianten der Schwingungsmessungen und der faseroptischen Sensorik zusätzliche Kenntnisse püber das Bauwerksverhalten ermittelt werden . In dem Beitrag werden die Verfahren mit ihren Möglichkeiten und Grenzen vorgestellt, die Ergebnissee an der Brücke in Brandenburg erläutert und zukünftige Einsatzmöglichkeiten diskutiert. Tübingen Expert Verlag Technische Akademie Esslingen (TAE) 2022 5. Brückenkolloquium, Tagungshandbuch 2022 978-3-8169-3549-0 5. Brückenkolloquium Ostfildern, Germany 06.09.2022 07.09.2022 555 566 2022-09-08 OPUS4-55656 Beitrag zu einem Tagungsband Eichner, Lukas; Gerards, Paul; Herrmann, Ralf; Schneider, Ronald; Hille, Falk; Baeßler, Matthias A framework for data and structural integrity management for support structures in offshore wind farms based on building information modelling Support structures of wind turbines in German offshore wind farms are regularly inspected. Currently, inspection outcomes are generally not systematically recorded. This prevents their consistent handling and processing, which is a key requirement to enable an efficient structural integrity management. As part of the DiMoWind-Inspect project, a data model and reference designation system for such inspection results is developed to facilitate their identification, localization, quantification, tracing and linking throughout the lifetime of a wind farm and beyond. The inspection results together with structural health monitoring results and information on repairs form the basis for assessing and predicting the structural condition, estimating the remaining lifetime, and planning of future inspections, structural health monitoring, and repairs. As a basis for developing a digital structural integrity management, a generic framework is proposed in this paper, which describes the stakeholders, data, models, processes and workflows of the integrity management of support structures in offshore wind farms and their interrelations. The framework adopts a building information modelling approach to describe the information relevant to the structural integrity management. The central digital space of the framework is a common data environment. An implementation of the framework will enable a digital structural integrity management in which inspection, structural health monitoring, repair, assessment and planning outcomes generated throughout the life cycle of a wind farm can be consistently collected, managed, shared and processed by the relevant shareholders. Singapore Research Publishing ISRERM Organizers 2022 Proc. of the 8th Intl. Symp. on Reliability Engineering and Risk Management (ISRERM 2022) 8th International Symposium on Reliability Engineering and Risk Management Hannover, Germany 04.09.2022 07.09.2022 111 117 10.3850/978-981-18-5184-1_MS-04-161-cd 2022-09-12 OPUS4-55472 Beitrag zu einem Tagungsband Baeßler, Matthias; Herrmann, Ralf; Hille, Falk; Wille, Frank Dynamisches Verhalten und Überwachung des Großen Fallturms der BAM in Horstwalde Falltürme sind Bauwerke, die als Versuchsanlagen sehr speziellen, impulsartigen Belastungen ausgesetzt sind. Am Fallturm auf dem Testgelände Technische Sicherheit (TTS) der BAM wurde bei Routineinspektionen eine Abnahme der strukturellen Integrität in Form von Vorspannungsverlusten in den Bolzen der Stahlverbindungen festgestellt. Um ein Verständnis für die zugrundeliegenden Trag- und Schädigungsmechanismen zu erlangen, wurde ein umfassendes Structural Health Monitoring (SHM) System geplant und am Bauwerk installiert unter Nutzung von digitalen Bauwerksmodellen. Für die Auslegung des Überwachungssystems, insbesondere aber zur Unterstützung der Untersuchung des Schädigungsprozesses, wurden Finite-Elemente-Modelle erstellt. Um sicherzustellen, dass die FE-Modelle das reale Tragwerksverhalten mit ausreichender Genauigkeit abbilden, mussten sie jedoch in Bezug auf die gemessenen Antworten des Tragwerks kalibriert werden. Der vorliegende Beitrag beschreibt experimentelle und numerische Untersuchungen zur Identifizierung des strukturellen Systems des Stahlrohrgitterturms in Vorbereitung einer Überwachungskampagne. Die Auswertung von gemessenen Schwingungen unter ambienter Anregung ermöglichte die Identifizierung der Eigenfrequenzen mehrerer globaler Schwingungsmoden des Fallturms. Zur Modellvalidierung wurde zunächst eine Sensitivitätsanalyse durchgeführt, um die Parameter mit dem größten Einfluss zu ermitteln. Anschließend wurde ein evolutionärer Algorithmus (EA) zur Optimierung nach dem Prinzip der Minimierung der Differenzen zwischen gemessenen und simulierten charakteristischen Antworten eingesetzt. Das aktualisierte Modell wurde schließlich an der dynamischen Reaktion der Turmstruktur infolge einer realen Falltest-induzierten Stoßbelastung validiert. Die Ergebnisse zeigten eine gute Übereinstimmung zwischen numerischen und experimentellen Ergebnissen. Düsseldorf VDI-Verlag VDI Wissensforum 2022 7. VDI-Fachtagung Baudynamik 2379 978-3-18-092379-6 7. VDI-Fachtagung Baudynamik Würzburg, Germany 27.04.2022 28.04.2022 265 284 10.51202/9783181023792-265 2022-08-11 OPUS4-55474 Beitrag zu einem Tagungsband Hille, Falk; Nerger, Deborah; Moosavi, Robabeh; Grunwald, Marcel Discussion on data evaluation of tomographic and numerical results The contribution discusses the processing and analysis of data generated on two different ways of investigations for impact damage in reinforced concrete structures. Damage investigations are essential to determine type and characteristics of damage and thus the residual capacity. Damage describing data is generated using two different types of investigation, a non-destructive tomographic as well as numerical examination. Subsequently, data of both sources was merged and analysed. Within the research project "Behaviour of structural components during impact load conditions caused by aircraft fuel tank collision" reinforces concrete plates were damaged by impact loading, see Hering (2020). Afterwards the damaged specimens were investigated tomographically as well as numerically using several methods and models. Aim of the presented research work was to specify an objective comparability of numerical data with experimentally determined damage patterns and based on this, to establish a quantitative damage evaluation. IASMIRT International Association for Structural Mechanics in Reactor Technology 2022 Proceedings of 26th International Conference on Structural Mechanics in Reactor Technology 26th International Conference on Structural Mechanics in Reactor Technology Potsdam, Germany 10.07.2022 15.07.2022 1 8 2022-08-11 OPUS4-56663 Zeitschriftenartikel Mendler, A.; Döhler, M.; Hille, Falk Detecting changes in boundary conditions based on sensitivity-based statistical tests Structural health monitoring is a promising technology to automatically detect structural changes based on permanently installed sensors. Vibration-based methods that evaluate the global system response to ambient excitation are suited to diagnose changes in boundary conditions, i.e., changes in member prestress or imposed displacements. In this paper, these changes are evaluated based on sensitivity-based statistical tests, which are capable of detecting and localizing parametric structural changes. The main contribution is the analytical calculation of sensitivity vectors for changes in boundary conditions (i.e., changes in prestress or support conditions) based on stress stiffening, and the combination with a numerically efficient algorithm, i.e., Nelson's method. One of the main advantages of the employed damage diagnosis algorithm is that, although it uses physical models for damage detection, it considers the uncertainty in the data-driven features, which enables a reliabilitybased approach to determine the probability of detection. Moreover, the algorithm can be trained and the probability of detecting future damages can be predicted based on data and a model from the undamaged structure, in an unsupervised learning mode, making it particularly relevant for unique structures, where no data from the damaged state is available. For proof of concept, a numerical case study is presented. The study assesses the loss of prestress in a two-span reinforced concrete beam and showcases suitable validation approaches for the sensitivity calculation. Kirchwald NDT.net 2022 E-journal of nondestructive testing 27 International Symposium on Non-Destructive Testing in Civil Engineering (NDT-CE 2022) Zurich, Switzerland 16.08.2022 18.08.2022 9 1 13 urn:nbn:de:kobv:b43-566632 https://creativecommons.org/licenses/by/4.0/deed.de 2022-12-21 OPUS4-56667 Vortrag Hille, Falk Structural Health Monitoring am Großen Fallturm der BAM Am Fallturm auf dem Testgelände Technische Sicherheit (TTS) der BAM wurden bei Inspektionen Vorspannungsverluste in den Bolzen der Stahlverbindungen festgestellt. Um ein Verständnis für die zugrundeliegenden Trag- und Schädigungsmechanismen zu erlangen und um den Zustand der vorgespannten Schraubverbindungen langzeitlich zu überwachen, wurde am Fallturm ein Structural Health Monitoring (SHM) System installiert. Für die Auslegung des Monitoringsystems sowie zur Unterstützung der Untersuchung des Schädigungsprozesses wurde ein numerisches Modell erstellt und in Bezug auf die gemessenen Antworten des Tragwerks kalibriert. Im Vortrag werden die experimentellen und numerischen Untersuchungen zur Systemidentifikation des Stahlrohrgitterturms als auch die Überwachungskampagne mit dem eingesetzten Monitoringsystem sowie die Messergebnisse und deren Bewertung vorgestellt. 2022 Seminar "Zerstörungsfreie Prüfung" am Lehrstuhl für Zerstörungsfreie Prüfung ,Technische Universität München Online meeting 13.01.2022 2022-12-21 OPUS4-57302 Zeitschriftenartikel Lehmann, F.; Hille, Falk Dauerüberwachung von Ingenieurbauwerken - Das neue Merkblatt B 09 der DGZfP Messtechnische Systeme zur Dauerüberwachung von Bauwerken ermöglichen Einblicke in deren reale Trag- und Verformungsverhalten. Die Planung und technische Umsetzung solcher Maßnahmen erfordern für die erfolgreiche Erfüllung der Aufgabenstellungen eine hohe Fachkompetenz, sowohl auf der planerischen Seite, als auch für die fachliche Bewertung von angebotenen Monitoringlösungen. Als Hilfestellung dafür wurde von der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) das Merkblatt „Dauerüberwachung von Ingenieurbauwerken" erarbeitet, welches nun verfügbar ist. In diesem Beitrag werden die Inhalte des neuen Merkblatts vorgestellt und dieses in die vorhandene Literatur eingeordnet. Ernst & Sohn 2023 Beton- und Stahlbetonbau 118 4 275 280 10.1002/best.202200122 2023-04-17 OPUS4-58341 Beitrag zu einem Tagungsband Fiedler, Georg; Hering, Marcus; Schubert, T.; Bracklow, F.; Nerger, Deborah; Hille, Falk; Beckmann, B. Wuttke, F.; Aji, H.; Özarmut, A. Schädigung von Stahlbetonplatten infolge eines harten Anpralls - Vergleich von halb-empirischen Methoden und experimentellen Ergebnissen Schutzbauwerke von systemkritischen Infrastruktureinrichtungen wie Betonwände und Betonbarrieren müssen Anprallereignissen oder schweren Unfällen in einem vertretbaren Maße widerstehen können. Anprallereignisse können verschiedenster Natur sein. Hierzu zählen Steinschlag, Fahrzeug- oder Flugzeuganprall oder auch Geschosseinschlag. Geschosseinschläge bzw. Bei den Anprall- oder Impaktereignissen wird zwischen hartem und weichem Anprall unterschieden, bei hartem Anprall verformt sich der Anprallkörper nicht oder nur geringfügig, bei weichem Anprall stark. In diesem Artikel werden Forschungsergebnisse zum harten Anprall auf bewehrte Stahlbetonplatten vorgestellt, welche über die letzten Jahre im Rahmen eines Kooperationsprojekts zwischen dem Institut für Massivbau (IMB) der Technischen Universität Dresden (TUD) und der Bundesanstalt für Materialforschung und -prüfung (BAM) durchgeführt wurden. Auf dem Gelände des Otto-Mohr-Labors (OML) der TUD steht hierfür ein speziell konzipierter Fallturm zur Verfügung. Der Aufbau im Fallturm lässt aktuell druckluftbeschleunigte Impaktversuche mit mittleren Anprallgeschwindigkeiten zu. Die durch Anprall geschädigten Stahlbetonplatten wurden anschließend bei der BAM mit Strahlung tomographisch untersucht. Diese Untersuchungen ermöglichen einen Blick auf die Schädigung und Rissstruktur im Inneren der Stahlbetonplatten. Ein Schwerpunkt der durchgeführten Untersuchung ist der Vergleich von Testergebnissen mit den häufig angewendeten halbempirischen Berechnungsmethoden zu den erforderlichen Wandstärken und den sich daraus ergebenden zulässigen Anprallgeschwindigkeiten. Bei diesem Vorgehen wird auch die mit analytischen Methoden abschätzbare Durchdringungsgeschwindigkeit bzw. Austrittgeschwindigkeit eines Projektils ermittelt und mit den realen Testergebnissen verglichen. Außerdem wird der Einfluss von sowohl externen als auch internen Strukturparametern auf Risse betrachtet und ein Fazit abgeleitet. Weiterhin werden laufende und zukünftige wissenschaftliche Untersuchungen zum Anprall auf Betonstrukturen am IMB und der BAM genannt. Deutsche Gesellschaft für Erdbebeningenieurwesen und Baudynamik (DGEB) e.V. 2023 18. D-A-CH-Tagung Erdbebeningenieurwesen und Baudynamik 978-3-930108-15-1 18. D-A-CH-Tagung Kiel, Germany 13.09.2023 15.09.2023 471 479 2023-09-18 OPUS4-57244 Beitrag zu einem Tagungsband Gerards-Wünsche, Paul; Ratkovac, Mirjana; Schneider, Ronald; Hille, Falk; Baeßler, Matthias A framework for assessing the reliability of crack luminescence - an automated fatigue crack detection system The new crack luminescence method offers the possibility of making fatigue surface cracks in metallic materials more visible during inspections through a special coating system. This coating system consists of two layers, whereby the first layer has fluorescent properties and emits visible light as soon as it is irradiated by UV light. The top layer is black and is designed to prevent the fluorescent layer from emitting if no crack develops in the underlying material. The technique proved particularly useful in a wide variety of fatigue tests of steel components under laboratory conditions. Moreover, it has the potential to be used in various industrial applications. To enable industrial deployment and integration into maintenance strategies, a concept study is developed in this contribution, resulting in a qualification framework that can serve as a foundation for determining the reliability of the crack luminescence system in terms of a probability of detection curve. Within this study, factors causing measurement variability and uncertainty are being determined and their influences assessed. Due to the extension of the system by a moving computer vision system for automated crack detection using artificial intelligence, additional long-term effects associated with structural health monitoring systems need to be incorporated into an extended probability of detection study as part of the technical justification. Finally, important aspects and findings related to design of experiments are discussed, and a framework for reliability assessment of a new optical crack monitoring method is presented, emphasizing the influence of various uncertainty parameters, including long-term effects such as system ageing. 2023 SPIE Conference Smart Structures + Nondestructive Evaluation 2023 978-1-5106-6086-1 SPIE Conference Smart Structures + Nondestructive Evaluation 2023 Long Beach, CA, USA 24.03.2023 28.03.2023 1 15 10.1117/12.2658390 2023-03-30