TY - CONF A1 - Rohrmann, Rolf T1 - Aufgaben der Dauerüberwachung am Beispiel von Betonbrücken und Windenergieanlagen T2 - Seminar "Messen im Bauwesen", BAM CY - Berlin, Germany DA - 2007-03-16 PY - 2007 AN - OPUS4-14750 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Bäumer, Stephan T1 - Dynamic investigations at offshore wind turbines T2 - EVACES'07 - Experimental vibration analysis for civil engineering structures CY - Porto, Portugal DA - 2007-10-24 KW - Structural Health Monitoring KW - Damage Identification KW - Wind turbines PY - 2007 SN - 978-972-752-095-4 SP - 965 EP - 976 AN - OPUS4-16278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Dynamic investigations at offshore wind turbines T2 - Experimental Vibration Anylysis for Civil Engineering Structures (EVACES´07) CY - Oporto, Portugal DA - 2007-10-24 PY - 2007 AN - OPUS4-16418 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Konzepte und Aufgaben der Dauerüberwachung von Ingenieurbauwerken T2 - Universität Hannover, Geodätisches Institut CY - Hanover, Germany DA - 2007-06-23 PY - 2007 AN - OPUS4-16419 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klement, Ernst A1 - Rudolphi, Reinald A1 - Rohrmann, Rolf T1 - Zur numerischen Abschätzung der stationären Wärmebeanspruchung von Dämmschichten in dreischaligen Hausschornsteinkonstruktionen PY - 1977 SN - 0341-2032 VL - 8 IS - 5 SP - 485 EP - 490 PB - Bauverlag BV CY - Gütersloh AN - OPUS4-1280 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Zustanduntersuchung und Dauerüberwachung von Bauwerken mit Hilfe modaler Parameter T2 - VDI-Schwingungstagung 2000 Experimentelle und rechnerische Modalanalyse sowie Identifikation dynamischer Systeme CY - Kassel, Germany DA - 2000-06-14 PY - 2000 AN - OPUS4-6562 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - M.: Zustanduntersuchung und Dauerüberwachung von Bauwerken mit Hilfe modaler Parameter T2 - VDI-Schwingungstagung 2000 'Experimentelle und rechnerische Modalanalyse sowie Identifikation dynamischer Systeme CY - Kassel, Germany DA - 2000-06-14 PY - 2000 AN - OPUS4-6657 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Structural Causes Of Temperature Affected Modal Data Of Civil Structures Obtained By Long Time Monitoring T2 - 18. Int. Modal Analysis Conference (IMAC) CY - San Antonio, TX, USA DA - 2000-02-07 PY - 2000 AN - OPUS4-6778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Rohrmann, Rolf-Günther A1 - Rudolphi, Reinald T1 - Bemessung und Optimierung beheizbarer Straßen- und Brückenbeläge N2 - Bemessung und Optimierung beheizbarer Straßen- und Brückenbeläge Beheizbare Straßen- und Brückenbeläge gewinnen im Hinblick auf bessere Verkehrssicherheit in besonders kritischen Bereichen Bedeutung. Darstellung realisierbarer Möglichkeiten und Systemen sowie ihrer optimalen Anwendung. T3 - BAM Forschungsberichtreihe - 53 PY - 1978 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-3979 SN - 0938-5533 VL - 53 SP - 1 EP - 76 PB - Bundesanstalt für Materialprüfung (BAM) CY - Berlin AN - OPUS4-397 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Cunha, A. A1 - Rogge, Andreas ED - De Stefano, A. T1 - Vibration-based structural health monitoring of a highway bridge based on continuous dynamic measurements during 14 years N2 - This paper presents the continuous dynamic measurements of an aging prestressed box-beam bridge during the period from 2000 to 2013, which consists of dynamic properties and environmental/operational factors, as well as the Variation of the extracted health features after removing the environmental/operational effects. Firstly, the variations of frequency estimates, temperatures and traffic loads from 2000 to 2013 are described. Subsequently, correlation analysis between them indicates the nonlinear influences of the temperature on the frequency estimates. The Multiple Linear Regression (MLR) method is used to remove the environmental/operational effects and the health index is proposed by performing the Novelty Detection analysis of the residual errors. Finally, the variations of the health index may indicate clear structural modifications that can be also characterized by the long term monitoring of the dynamic strain in the prestressed cable. T2 - SHMII-7 - 7th International conference on structural health monitoring of intelligent infrastructure CY - Torino, Italy DA - 01.07.2015 KW - Westend bridge PY - 2015 SP - 1 EP - 12 AN - OPUS4-35124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rücker, Werner A1 - Baeßler, Matthias A1 - Rohrmann, Rolf ED - Rackwitz, F. T1 - Experimentelle Untersuchungen zu Schotterfahrwegen auf Brücken N2 - Auf Schnellfahrstrecken können Brückentragwerke durch die Überfahrt von Zügen zu Resonanzschwingungen angeregt werden. Dies führt ungünstigstenfalls zu übermäßigen Beschleunigungen des Brückendecks infolge derer sich das Schotterbett destabilisiert. In diesem Beitrag wird die Wirkung von vertikalen Brückenschwingungen auf den Schotteroberbau anhand experimenteller Untersuchungen beschrieben. T2 - Festschrift zum 60. Geburtstag von Univ.-Professor Dr.-Ing. habil. Stavros A. Savidis KW - Schotteroberbau KW - Beschleunigung KW - Eisenbahnbrücken KW - Gleislage KW - Destabilisierung KW - Unterschottermatten PY - 2006 SN - 3-540-27425-1 DO - https://doi.org/10.1007/3-540-27438-3_26 SP - 397 EP - 414 PB - Springer CY - Berlin AN - OPUS4-11493 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rücker, Werner A1 - Rohrmann, Rolf A1 - Hille, Falk T1 - Guidelines for monitoring and assessment - A SAMCO initiative as a basis for the international standardization T2 - 2nd International Conference on Structural Health Monitoring and Intelligent Infrastructure CY - Shenzhen, China DA - 2005-11-16 KW - Monitoring KW - Zustandsüberwachung KW - Schadensanalyse KW - Windlasten KW - Dynamik KW - Windenergieanlagen KW - Offshore KW - Bauliche Bewertung PY - 2006 SN - 0-415-39652-2 SP - 1671 EP - 1676 PB - Taylor & Francis CY - London AN - OPUS4-11566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Hille, Falk A1 - Rohrmann, Rolf A1 - Rücker, Werner ED - Parke, G. ED - Disney, P. T1 - Guideline for the assessment of existing structures T2 - 5th International Conference on Bridge Management, "Bridge Management 5, Inspection, maintenance, assessment and repair" CY - Guildford, England, UK DA - 2005-04-11 KW - Monitoring KW - Zustandsüberwachung KW - Dynamik KW - Brücken KW - Bauliche Bewertung PY - 2005 SN - 0-7277-3354-0 SP - 227 EP - 234 PB - Thomas Telford CY - London AN - OPUS4-11680 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Plauk, Günther A1 - Kretschmann, Günter A1 - Rohrmann, Rolf-Günther T1 - Untersuchung des baulichen Zustandes und der Tragfähigkeit vorgespannter Riegel von Verkehrszeichenbrücken der Berliner Stadtautobahn N2 - Ergebnisse der an den Spannbetonriegeln durchgeführten Untersuchungen. Schwerpunkte waren Begutachtung des Zustandes der Betonoberflächen, Ermittlung der Betondruckfestigkeit, der Karbonatisierungstiefe, der Konzentration und Eindringtiefe von Chloriden, Ermittlung der Tragfähigkeit im Belastungsversuch, etc. T3 - BAM Forschungsberichtreihe - 152 KW - Autobahnwegweiserbrücken KW - Spannbeton KW - Spannbetonträger KW - Bewehrungskorrosion KW - Belastungsversuche KW - Schwingungsanalyse KW - Zerstörungsfreie Prüfung PY - 1988 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-2981 SN - 978-3-88314-796-6 SN - 0938-5533 VL - 152 SP - 1 EP - 94 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-298 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz A1 - Said, Samir A1 - Rohrmann, Rolf ED - Döhler, Michael T1 - Modal analysis of road and rail bridges for damage detection and resonance prediction N2 - In the 1980s, the Federal Institute of Material Research and Testing started with modal analysis measurements of some bridges before and after repair. For one of the bridges, a structural health monitoring was installed 1994 which is still working up to now. It has been modified and extended several times. The monitoring was extended from the critical span to three neighbouring spans. A modal analysis of the whole bridge with seven spans have been done three times, twice together with EMPA of Switzerland. Additional calibration measurements have been done and additional evaluation procedures have been implemented for the monitoring of the steadily increasing loads from the road traffic. Additional sensors were installed such as strain gauges, crack-width, and temperature sensors. The strong influence of the temperature on the natural frequencies has been studied over the years. Later, a temperature compensation has been established and a weak aging trend has been found in the monitoring data. Now, the bridge will be demolished and replaced by a new bridge. Some results of this long-term monitoring will be shown and possible damages (changes of the pre-stress or the support structure) will be discussed. A second application of modal analysis will be demonstrated: the prediction of the resonances due to passing trains. The response of a bridge to passing trains can be calculated in frequency domain as the multiplication of three spectra, the axle sequence spectrum of the train, the transfer function of the bridge, and the modal force spectrum of a single passing load. A resonance occurs if a maximum of the train spectrum coincides with the maximum of the bridge spectrum. The amplitude at this resonance is strongly influenced by the modal force spectrum which is identical to the frequency or wavenumber spectrum of the corresponding mode shape. Therefore, modal analysis from calculation, impact measurements, wind and train measurements are necessary for the prediction of the resonance occurrence and amplification. Examples of mode shape spectra for single or multi-span bridges with simply supported or continuous spans will be shown, and some relations between mode shapes and resonance amplifications will be concluded. T2 - 11th International Operational Modal Analysis Conference (IOMAC) CY - Rennes, France DA - 20.05.2025 KW - Bridge monitoring KW - Multi-span bridges KW - Damage detection KW - Resonance PY - 2025 SP - 39 EP - 46 PB - INRIA CY - Rennes AN - OPUS4-63473 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Thöns, Sebastian A1 - Rücker, Werner A1 - Bicker, S. A1 - Said, Samir A1 - Schmid, Wolfgang T1 - Structural investigations and monitoring results on a prototype of offshore wind turbines of multibrid M5000 series N2 - The concept and technical details of the implementation of the developed integrated monitoring system within the IMO-WIND project are presented. The tasks of the components of the system and its requirements are described. Selected results from the continuous monitoring during operation of the plant M5000_2 regarding the task design verification and dynamic structural analysis are given. T2 - DEWEK 2010 - 10th German wind energy conference CY - Bremen, Germany DA - 2010-11-17 KW - Integrated monitoring system KW - Offshore wind turbines KW - Design verification KW - Structural assessment KW - Limit values KW - Load transfer KW - Data management KW - Dynamic analysis KW - Rotor blades KW - Embedded sensors PY - 2011 IS - S03 SP - 1 EP - 5 PB - DEWI GmbH AN - OPUS4-23712 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rohrmann, Rolf A1 - Thöns, Sebastian A1 - Rücker, Werner T1 - Integrated monitoring of offshore wind turbines - requirements, concepts and experiences N2 - Wind turbines on offshore sites (OWECs) are subjected to combined loads from wind and waves. These dynamic loads, with a frequency content within the range of the natural frequencies of the structures, cause fatigue-effective stresses in the substructures of wind turbines. Therefore, the examination of natural frequencies is an important part within the design process of wind turbines. The quality of the numerical models for such calculations is of great importance, since the certification guidelines permit only small uncertainties in modal analysis results. The accuracy of the parameters of the numerical model can only be achieved through a comparison of simulation results with corresponding test results. Therefore, it is necessary to measure the dynamic behaviour of all components of the wind turbines simultaneously. This is true not only for the design verification, but also for monitoring the OWECs in operation. The potential of integrated systems for monitoring-based maintenance optimisation should thus be used. KW - Offshore wind turbines KW - Integrated monitoring system KW - Structural assessment KW - Damage indicators KW - Dynamic loads KW - Data management PY - 2010 DO - https://doi.org/10.1080/15732470903068706 SN - 1573-2479 SN - 1744-8980 VL - 6 IS - 5 SP - 575 EP - 591 PB - Taylor & Francis CY - London AN - OPUS4-21452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Thöns, Sebastian A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Faber, M.H. T1 - Bewertung der Ermüdungsfestigkeit von Baustrukturen in Offshore-Windenergie-Anlagen N2 - Das Bauwerk einer Windenergieanlage dient der Sicherstellung der Energieproduktion. Eine entsprechende Zuverlässigkeit der Struktur und deren permanente Bewertung und Unterhaltung ist dazu notwendig. In diesem Beitrag werden Möglichkeiten der Bewertung des für die Struktur wichtigen Schädigungsmechanismus Ermüdung sowie dessen Überwachung in Zusammenhang mit Schädigungsindikatoren aufgezeigt. Dabei wird auf strukturmechanische, werkstoffmechanische und probabilistische Modelle sowie auf Messdaten eines Prototyps einer OWEA zurückgegriffen. Ausgehend von der gesamtdynamischen Berechnung wird die Zuverlässigkeit gemäß der Auslegung für den Schädigungsmechanismus Ermüdung durch ein Wöhlerlinienmodell berechnet. Damit werden ermüdungssensible Komponenten der Struktur identifiziert. Schädigungsindikatoren zur Überwachung der Ermüdungsfestigkeit werden auf Grundlage schädigungs-äquivalenter Dehnungen vorgestellt. Fatigue assessment of support structures for offshore wind energy converters. The structure of wind energy converters secures a reliable energy production. Hence an adequate reliability of the structure and additionally permanent assessment and maintenance is required. Within this paper methods for the assessment of the important damage mechanism fatigue in combination with monitoring of the fatigue reliability utilizing damage indicators are proposed. These methods comprise structural system, material degradation and probabilistic models as well as monitoring data of an offshore wind energy converter prototype. The structural reliability of the structure as designed is calculated based on an overall dynamic analysis using a SN-approach. Herewith fatigue sensitive components are identified. Damage indicators for monitoring the fatigue reliability based on damage equivalent strains are presented. KW - Bewertung KW - Offshore-Windenergie KW - Ermüdung KW - Strukturspannungskonzept KW - Zuverlässigkeit KW - Schadensindikatoren KW - Integrated Monitoring System KW - Damage Identification KW - Load Monitoring KW - Wind turbines PY - 2008 DO - https://doi.org/10.1002/stab.200810076 SN - 0038-9145 SN - 1437-1049 SN - 0932-6375 VL - 77 IS - 9 SP - 630 EP - 638 PB - Ernst CY - Berlin AN - OPUS4-17977 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Thöns, Sebastian A1 - Said, Samir A1 - Schmid, Wolfgang T1 - Ergebnisse der Dauerüberwachung an einem Prototypen von Offshore-Windenergieanlagen T2 - 3. VDI-Fachtagung - Baudynamik CY - Kassel, Deutschland DA - 2009-05-14 KW - Integrated Monitoring System KW - Offshore wind turbines KW - Assessment KW - Damage identification KW - Load monitoring PY - 2009 SN - 978-3-18-092063-4 SN - 0083-5560 VL - 2063 SP - 455 EP - 466 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-19795 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Thöns, Sebastian T1 - Design-Verifikation von Offshore-Windenergieanlagen mit Hilfe integraler Überwachungssysteme T2 - Finales Statusseminar zum Forschungsvorhaben IMO-WIND CY - Berlin, Germany DA - 2009-10-01 PY - 2009 AN - OPUS4-20077 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Thöns, Sebastian T1 - Integrated Monitoring Systems for Offshore Wind Turbines T2 - 6th International Workshop on Structural Health Monitoring CY - Stanford, USA DA - 2007-09-11 KW - Integrated Monitoring System KW - Damage Identification KW - Load Monitoring KW - Wind turbines PY - 2007 SP - 1 EP - 8 AN - OPUS4-16280 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Thöns, Sebastian A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Rücker, Werner T1 - Vibration-based structural health monitoring of a wind turbine system. Part II: Environmental/operational effects on dynamic properties N2 - The second part of these companion papers mainly researches environmental/operational influences on structural dynamic properties under normal operational conditions during two years, in order to extract a statistical based damage-sensitive indicator for health monitoring of a wind turbine system. The correlation analyses between experimental identified frequencies, damping values as well as mode shapes and environmental/operational factors such as rotation speed of blades, wind speed, pitch angle, temperature and nacelle direction are presented. It is observed that the frequency estimates are influenced by the nacelle position, the activation of rotor, the rotation speed of blades and the wind speed as well as the temperature. Regarding to the damping estimates, they are mainly associated with variation of the aerodynamic damping due to the increasing wind speed. Besides, the resonance phenomenon is also observed in higher modes. The harmonic frequencies due to blades passing by tower are found and the corresponding damping value decreases. Moreover, the mode shapes in some modes are strongly affected by the position of the nacelle. Subsequently, two types of simulated damage including the reduction of stiffness in both the rotor blade and the tubular tower are successfully detected by applying the Principal Component Analysis (PCA) based methods to these temperature-sensitive frequency estimates. Comparison of change of the extracted health features indicates that they are more sensitive with the tower damage. KW - Vibration KW - Structural health monitoring KW - Wind turbine KW - Environmental/operational effects KW - Modal properties KW - Principal Component Analysis KW - Novelty analysis KW - Damage detection KW - Sommerfeld effect KW - Automated operational modal analysis KW - Resonance PY - 2015 DO - https://doi.org/10.1016/j.engstruct.2014.12.035 SN - 0141-0296 VL - 89 SP - 273 EP - 290 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32879 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hu, Wei-Hua A1 - Thöns, Sebastian A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Rücker, Werner T1 - Vibration-based structural health monitoring of a wind turbine system. Part I: Resonance phenomenon N2 - This paper is focused on a resonance phenomenon of a wind turbine system in 5 MW class, on the basis of dynamic signals acquired continuously from the tubular tower under normal operational conditions during two years. Firstly, technique specifications of the wind turbine system are introduced and a finite element model is developed to characterize the structural dynamic properties. The following part describes the continuous dynamic monitoring system integrated with an automated operational modal analysis procedure using the poly-reference Least Squares Complex Frequency domain (p-LSCF) method. Subsequently, variations and mutual relationships of environmental/operational factors such as vibration amplitude, temperature, wind speed, rotation speed of blades, pitch angle and nacelle direction are also presented. Finally, significant resonance is observed due to the fundamental frequency of the tower matching with the harmonic frequency induced by the rotation of three blades. As the rotation speed of rotor approaches to 8 rpm, the vibration amplitude of the tower increases significantly and the corresponding damping value decreases. With the further rising wind velocity, the rotation speed of blades stops increasing and the input energy just contribute to accumulate the vibration amplitude of tower. Such observation indicates the Sommerfeld effect that aggravates the resonance phenomenon. A vibration control device is necessary to minimize the excessive structural responses. A companion paper will further discuss the environmental/operational effects on dynamic properties of the wind turbine system under the operational conditions. KW - Vibration KW - Structural health monitoring KW - Wind turbine KW - Automated operational modal analysis KW - Resonance KW - Sommerfeld effect PY - 2015 DO - https://doi.org/10.1016/j.engstruct.2014.12.034 SN - 0141-0296 VL - 89 SP - 260 EP - 272 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-32878 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Thöns, Sebastian A1 - Said, Samir T1 - Design and operation of integrated monitoring systems for offshore wind turbines N2 - To ensure a high operational reliability of future generations of offshore wind conversion systems (OWEC) with economically acceptable repair and maintenance efforts, comprehensive diagnosis and supervision concepts are required. Automatic monitoring systems will be an essential part of such concepts. Because of the fact, that during operation there will be static and dynamic interaction between the components 'structure', 'machinery' and 'blades' it is necessary to develop the monitoring techniques in an overall concept. These monitoring systems are supposed to be applied for the design and testing as well as for the operation and maintenance phases. The used methods are focused on the design requirements for the structure, which are stated in the respective standards and certification guidelines. For the validation of the design, methods are specified which would be also applicable for SHM in the operating condition, e.g. for the evaluation of the structural conditon possibly after the occurrence of damages or changes. The further task consists in the realization of condition monitoring for all components, aiming at early damage detection and the observation of the damage development and its evaluation. Here the task consists of determining with assessment procedures the optimum time for maintenance actions to be carried out. T2 - DEWEK 2008 - 9th German wind energy conference CY - Bremen, Germany DA - 2008-11-26 KW - Integrated monitoring system KW - Offshore wind turbines KW - Assessment KW - Damage identification KW - Load monitoring PY - 2008 SP - 1 EP - 4(?) AN - OPUS4-19872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf A1 - Said, Samir A1 - Schmid, Wolfgang A1 - Thöns, Sebastian A1 - Bicker, S. A1 - Rücker, Werner ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - Results from monitoring and assessment of offshore wind turbines N2 - To ensure a high operational reliability of offshore wind turbines (OWEC) with economically acceptable repair and maintenance efforts, comprehensive diagnosis and supervision concepts are required. Automatic monitoring Systems will be an essential part of such concepts. Because of the fact, that during Operation there will be static and dynamic interaction between the components ‘structure’, ‘machinery’ and ‘blades’ it is necessary to develop the monitoring techniques in an overall concept. These monitoring Systems are supposed to be applied for the design and testing as well as for the Operation and maintenance phases. The knowledge of the dynamic behavior of wind turbines is important both for the design and for a safe Operation. The available monitoring data from a period of three years, allow first conclusions on the long-term Operation of such Systems in terms of quality requirements to the instrumentation to the structure and the rotor blades T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Integrated monitoring system KW - Offshore wind turbines KW - Structural assessment KW - Limit values KW - Measurement hardware KW - Data management KW - Embedded FBG sensors KW - Data analysis KW - Damage detection KW - Rotor blades PY - 2011 SN - 978-90-760-1931-4 IS - MS25 SP - 3450 EP - 3456 AN - OPUS4-24293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rücker, Werner A1 - Rohrmann, Rolf T1 - Assessment and Damage Detection for Offshore Wind Turbines and Infrastructures T2 - IRIS - Current Praxis Workshop CY - Thessaloniki, Greece DA - 2009-03-30 PY - 2009 AN - OPUS4-20663 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Structural Investigations and Monitoring Results on a Prototype of Offshore Wind Turbines of Multibrid M 5000 Series T2 - DEWEK 2010, 10th German Wind Energy Conference CY - Bremen, Germany DA - 2010-11-17 PY - 2010 AN - OPUS4-22733 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Teng, Jun A1 - Tang, De-Hui A1 - Zhang, Xiao A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf G. T1 - Automated modal analysis for tracking structural change during construction and operation phases N2 - The automated modal analysis (AMA) technique has attracted significant interest over the last few years, because it can track variations in modal parameters and has the potential to detect structural changes. In this paper, an improved density-based spatial clustering of applications with noise (DBSCAN) is introduced to clean the abnormal poles in a stabilization diagram. Moreover, the optimal system model order is also discussed to obtain more stable poles. A numerical Simulation and a full-scale experiment of an arch bridge are carried out to validate the effectiveness of the proposed algorithm. Subsequently, the continuous dynamic monitoring system of the bridge and the proposed algorithm are implemented to track the structural changes during the construction phase. Finally, the artificial neural network (ANN) is used to remove the temperature effect on modal frequencies so that a health index can be constructed under operational conditions. KW - Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475116 UR - https://www.mdpi.com/1424-8220/19/4/927/pdf DO - https://doi.org/10.3390/s19040927 SN - 1424-8220 VL - 19 IS - 4 SP - 927, 1 EP - 23 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-47511 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Design and Operation of Integrated Monitoring Systems for Offshore Wind Turbines T2 - 9th German Wind Energy Conference, DEWEK 2008 CY - Bremen, Germany DA - 2008-11-26 PY - 2008 AN - OPUS4-18608 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Monitoring komplexer Anlagen am Beispiel von Offshore-Windenergieanlagen T2 - VDI/VDE Expertenforum 2011, Strukturmonitoring und Zustandsüberwachung CY - Nuremberg, Germany DA - 2011-06-07 PY - 2011 AN - OPUS4-23996 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Results from monitoring and assessment of offshore wind turbines T2 - Eurodyn 2011, 8th International Conference on Structural Dynamics CY - Leuven, Belgium DA - 2011-07-04 PY - 2011 AN - OPUS4-24082 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Integrale Systeme für die Strukturüberwachung, Dauerüberwachung der Anlagenteile "Bauwerk" und "Rotorblätter" T2 - AMA Fachverband für Sensorik: Fokussierte Thementage "Sensorik und Messtechnik für die Windenergie" CY - Mainz, Germany DA - 2011-12-01 PY - 2011 AN - OPUS4-25135 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Ergebnisse der Dauerüberwachung an einem Prototyp von Offshore-Windenergieanlagen T2 - 3. VDI-Fachtagung Baudynamik CY - Kassel, Germany DA - 2009-05-14 PY - 2009 AN - OPUS4-19773 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rohrmann, Rolf T1 - Monitoring Loads and Operational Demands at Wind Power Plants - Interaction between Tower and Rotor Blades T2 - 3rd Technical Conference WindTurbine Rotor Blades CY - Essen, Germany DA - 2011-06-28 PY - 2011 AN - OPUS4-24083 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Thöns, Sebastian A1 - Faber, M.H. A1 - Rücker, Werner A1 - Rohrmann, Rolf ED - Martorell, S. ED - et al., T1 - Assessment and monitoring of reliability and robustness of offshore wind energy converters T2 - ESREL 2008 CY - Valencia, Spain DA - 2008-09-22 KW - Structural reliability KW - Robustness KW - Monitoring KW - Risk KW - Wind energy converter PY - 2008 SN - 978-0-415-48513-5 SP - 1567 EP - 1572 PB - Taylor & Francis CY - London, UK AN - OPUS4-18565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -