TY - CONF A1 - Pirskawetz, Stephan A1 - Thiele, Marc A1 - Löhr, Manuel A1 - Loewe, Anna A1 - Degener, Sebastian A1 - Herrmann, Ralf T1 - Acoustic emission for monitoring of fatigue damage in concrete elements of wind turbine towers N2 - Wind energy has become an important player in the energy transition in Germany. Towers of onshore wind turbines are often designed as hybrid structures: the lower part is made of prestressed concrete whereas the upper part is made of steel tubes. The tall structures are permanently subjected to cyclic loads. A research project of BAM as part of the joint project WinConFat - Structure focusses on the evelopment of techniques to monitor fatigue damage evolution in the concrete part. Results of a previous project show that a combination of ultrasonic and acoustic emission testing can give an indication for critical conditions near the end of the fatigue life of the concrete. In the ongoing project acoustic emission sensors have been installed at the base and at the transition piece between concrete and steel of a hybrid wind turbine tower. Beside of acoustic emission measurement the sensor spacing allows for measuring the concrete ultrasonic velocity along the circumference in both levels. Additional measurements like strain, temperature, inclination, or acceleration allow for comparison of environmental loads and change of acoustic properties of the concrete. The paper focusses on first acoustic measurements recorded since December 2023 in comparison to operating data of the wind turbine. T2 - EWGAE2024: 36th Conference of the European Working Group on Acoustic Emission CY - Potsdam, Germany DA - 18.09.2024 KW - Concrete fatigue monitoring KW - Acoustic emission KW - Ultrasound KW - Hybrid wind turbine tower PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612197 DO - https://doi.org/10.58286/30234 SN - 1435-4934 VL - 29 IS - 10 SP - 1 EP - 9 AN - OPUS4-61219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Simon, Patrick A1 - Schneider, Ronald A1 - Baeßler, Matthias A1 - Recknagel, Christoph ED - Cunha, Á. ED - Caetano, E. T1 - Enhancing structural models with material tests and static response data - a case study considering a steel beam with asphalt layer subject to temperature variations N2 - Gradual or sudden changes in the state of structural systems caused, for example, by deterioration or accidental load events can influence their load-bearing capacity. Structural changes can be inferred from static and/or dynamic response data measured by structural health monitoring systems. However, they may be masked by variations in the structural response due to varying environmental conditions. Particularly, the interaction of nominally load-bearing components with nominally non-load bearing components exhibiting characteristics that vary as a function of the environmental conditions can significantly affect the monitored structural response. Ignoring these effects may hamper an inference of structural changes from the monitoring data. To address this issue, we adopt a probabilistic model-based framework as a basis for developing digital twins of structural systems that enable a prediction of the structural behavior under varying ambient condition. Within this framework, different types of data obtained from real the structural system can be applied to update the digital twin of the structural system using Bayesian methods and thus enhance predictions of the structural behavior. In this contribution, we implement the framework to develop a digital twin of a simply supported steel beam with an asphalt layer. It is formulated such that it can predict the static response of the beam in function of its temperature. In a climate chamber, the beam was subject to varying temperatures and its static response wass monitored. In addition, tests are performed to determine the temperature-dependent properties of the asphalt material. Bayesian system identification is applied to enhance the predictive capabilities of the digital twin based on the observed data. T2 - International Conference on Structural Health Monitoring of Intelligent Infrastructure (SHMII-10) CY - Online meeting DA - 30.06.2021 KW - Digital twin KW - Structural health monitoring KW - Material tests KW - Bayesian updating PY - 2021 SN - 2564-3738 SP - 1537 EP - 1544 AN - OPUS4-54126 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Deresse, N. E. A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Sarem, M. A1 - Francois, St. A1 - Verstrynge, E. T1 - Evaluation of Concrete Fatigue Damage with Elastic Wave-based Measurement Techniques N2 - The fatigue damage evolution and the fatigue life of quasi-brittle materials such as concrete are not yet completely understood. Accordingly to get better insights, researchers have recently been incorporating advanced measuring techniques in their fatigue experiments. In this research, acoustic emission techniques (AET), active ultrasonic, and deformation measurements are used to track the damage evolution of concrete samples subjected to fatigue loading. The samples are subjected to constant amplitude and stepwise fatigue loading in Brazilian splitting test set-ups. Initially, a good agreement is observed between the deformation and the ultrasonic measurements in capturing the crack propagation during Brazilian splitting tests. The three fatigue damage phases could be identified with all of the three techniques. The Phase II damage rates quantified by deformation measurements and AET in stepwise fatigue tests were used to predict the number of cycles to failure at various stress levels. The predictions were validated using the number of cycles to failure of the constant amplitude fatigue tests. T2 - 36th Conference of the European Working Group on Acoustic Emission CY - Potsdam, Germany DA - 18.09.2024 KW - Concrete KW - Acoustic emission KW - Ultrasonic testing KW - Fatigue PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615677 DO - https://doi.org/10.58286/30228 SN - 1435-4934 VL - 29 IS - 10 SP - 1 EP - 10 PB - NDT.net AN - OPUS4-61567 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hille, Falk A1 - Wedel, Frederik A1 - Lehmann, Frank A. A1 - Pirskawetz, Stephan ED - Lienhart, Werner ED - Krüger, Markus T1 - Structural health monitoring guidelines for bridges in Germany N2 - With the advancement of digitalization and related technological developments, Structural Health Monitoring (SHM) has become a useful and increasingly widespread tool to assist in the maintenance management of bridges and other engineering structures. The process of implementing monitoring requires expertise in many fields such as civil engineering, bridge operation and maintenance, monitoring technology, and data analysis. In recent years, monitoring has moved from method and technology development to standard practice. However, the implementation of monitoring as a standardized process can be an obstacle, especially for bridge operators, due to a lack of practical experience combined with the various expertise required. This can affect several areas, such as determining the cost-effectiveness of a monitoring measure, proper tendering and contracting, quality control, analysis and evaluation of measurement data, and last but not least, data management. In order to support the introduction of monitoring technologies into the practice of infrastructure operators, several guidelines have been developed in Germany in recent years by different interest groups, each with a different focus and essentially complementing each other. This paper aims to provide an overview of four different recently published guidelines and to highlight their strengths and advantages. T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure CY - Graz, Austria DA - 01.09.2025 KW - Structural Health Monitoring KW - Bridge structures KW - Guidelines PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643809 DO - https://doi.org/10.3217/978-3-99161-057-1-064 SP - 420 EP - 427 PB - Verlag der Technischen Universität Graz AN - OPUS4-64380 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -