TY - JOUR A1 - Johann, Sergej A1 - Strangfeld, Christoph A1 - Zimmek, David A1 - Bartholmai, Matthias T1 - Smart electronic helper for long-term monitoring of bridges and building structures N2 - Increasing traffic volume on the one hand and ageing infrastructure on the other hand have created many new challenges for maintenance and structural health monitoring of roads and bridges. In the past, many bridges and road structures have been neglected, often resulting in traffic congestion, road closure, and increased repair costs. This research is concerned with the development of a system to improve the challenge of maintenance and early detection of damage, particularly moisture penetration and corrosion of steel reinforced concrete components. The objective is to develop a method that will also work after 30 years and longer. Many new IoT solutions are equipped with internal energy storage elements (accumulators or batteries) which are inappropriate here, since most relevant signs of concrete degradation occur after decades, where the functioning of such elements are more than questionable. The presented technology approach uses radio-frequency identification (RFID) and enables connectivity to sensors. It offers the advantage of an passive, completely independent energy supply without any energy storage components. Since the system should be permanently embedded in concrete, it is crucial to develop a long-term stable device which is adapted to the environmental influences of the structure, e.g., long-term resistance in very alkaline environment of pH 13. In numerous experiments, the robustness of the system was tested and evaluated. Various tests with encapsulations to protect the electronics were performed, and for long-term validation different concrete specimens were instrumented with RFID-sensor-systems. Their operating time is now around two years and investigations for signs of fatigue and damage to the encapsulation and the electronics are ongoing. T2 - SMAR 2019 CY - Potsdam, Germany DA - 27.08.2019 KW - Sensors KW - Passive RFID KW - Smart structures KW - SHT KW - Long term monitoring PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501931 UR - https://www.ndt.net/?id=25011 SN - 1435-4934 VL - 25 IS - 1 SP - 1 EP - 6 PB - NDT.net CY - Kirchwald AN - OPUS4-50193 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Johann, Sergej A1 - Stührenberg, Jan A1 - Tandon, Aditya A1 - Dragos, Kosmas A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph A1 - Smarsly, Kay T1 - Investigation of long-term embedded RFID sensors for structural health monitoring N2 - Ensuring the health of civil engineering structures is crucial for the safety and longevity of the built environment. In this direction, structural health monitoring (SHM) has been increasingly employed, providing insight into the structural behavior, based on sensor data representing structural responses. This paper investigates the plausibility of embedding sensors into concrete structures for SHM, leveraging radio frequency identification (RFID) technology, in an attempt to enable the passive operation of sensors without continuous power supply and to reduce potential sources of interference. In contrast to conventional SHM sensors, the uninterrupted operation of embedded sensors must be ensured because post-installation interventions are either impractical or impossible. RFID technology enables wireless data acquisition and energy transmission without mechanical impact on civil engineering structures, although it may be challenging when RFID sensors are embedded in concrete. This study presents a durable passive embedded RFID sensor system (i.e., a system without batteries), including the selection of components, such as housing and cable materials, suitable for withstanding the aggressive environment of concrete without damaging the sensitive electronics or contaminating the data recorded by the sensors. The proposed sensor system is validated in laboratory tests, the results of which provide insights into the influence of each component and are intended to advance the implementation of embedded sensor systems. T2 - IEEE Sensors 2024 CY - Kobe, Japan DA - 20.10.2024 KW - Structural health monitoring KW - RFID-based sensors KW - Smart sensors KW - Embedded sensors PY - 2024 SN - 979-8-3503-6351-7 DO - https://doi.org/10.1109/SENSORS60989.2024.10785220 SP - 1 EP - 4 AN - OPUS4-62162 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bartelmeß, Jürgen A1 - Zimmek, David A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph A1 - Schäferling, M. T1 - Fibre optic ratiometric fluorescence pH sensor for monitoring corrosion in concrete N2 - In this communication a novel concept for pH sensing is introduced which is specifically adapted to monitor carbonation induced corrosion in concrete structures. The method is based on a ratiometric measurement principle, exploiting the pH sensitive colour switching of thymol blue in the basic pH regime and the emissive properties of two different (Zn)CdSe/ZnS core shell quantum dots. The transition point of thymol blue in a Hydrogel D4 matrix was determined to be at around pH 11.6, which fits ideally to the intended application. Next to the fundamental spectroscopic characterization of the ratiometric response, a new design for a sensor head, suitable for the incorporation into concrete matrices is presented. Toward this, a manufacturing process was developed which includes the preparation of a double layer of polymers containing either thymol blue or a quantum dot mixture inside a porous ceramic tube. Results of a proof-of-priciple performance test of the sensor head in solutions of different pH and in cement specimens are presented, with encouraging results paving the way for future field tests in concrete. KW - Fiber optic sensing KW - PH monitoring in concrete KW - Embedded sensors KW - Ratiometric fluorescence PY - 2020 DO - https://doi.org/10.1039/c9an02348h VL - 145 IS - 6 SP - 2111 EP - 2117 PB - Royal Society of Chemistry AN - OPUS4-50381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Neumann, Patrick P. A1 - Grotelüschen, Bjarne A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph ED - Kossa, A. ED - Kiss, R. T1 - Towards Autonomous NDT Inspection: Setup and Validation of an Indoor Localization System N2 - Monitoring and maintenance of civil infrastructure are of great importance, as any undetected damage can cause high repair costs, unintended deadtime, or endanger structural integrity. The inspection of large concrete structures such as bridges and parking lots is particularly challenging and time-consuming. Traditional methods are mostly manual and involve mapping a grid of measurement lines to record the position of each measurement. Current semi-automated methods, on the other hand, use GPS or tachymeters for localization but still require trained personnel to operate. An entirely automated approach using mobile robots would be more cost- and time-efficient. While there have been developments in using GPS-enabled mobile robots for bridge inspection, the weak signal strength in indoor areas poses a challenge for the automated inspection of structures such as parking lots. This paper aims to develop a solution for the automated inspection of large indoor concrete structures by addressing the problem of robot localization in indoor spaces and the automated measurement of concrete cover and rebar detection. T2 - 39th Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Siófok, Hungary DA - 26.09.2023 KW - NDT Inspection KW - Mobile Robot KW - Indoor Localization KW - Setup and Validation PY - 2023 SN - 978-963-421-927-9 SP - 88 EP - 89 PB - Hungarian Scientific Society of Mechanical Engineering (GTE) CY - Siófok, Hungary AN - OPUS4-58660 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Johann, Sergej A1 - Stührenberg, Jan A1 - Tandon, Aditya A1 - Dragos, Kosmas A1 - Bartholmai, Matthias A1 - Strangfeld, Christoph A1 - Smarsly, Kay T1 - Implementation and validation of robot-enabled embedded sensors for structural health monitoring N2 - In the past decades, structural health monitoring (SHM) has matured into a viable supplement to regular inspections, facilitating the execution of repair and maintenance work in the early stages of structural damage. With the advent of wireless technologies and advancements in information and communication technologies, civil infrastructure has been increasingly instrumented with wireless sensor nodes to record, analyze, and communicate data relevant to SHM. A promising method for SHM is to embed sensors directly into concrete for recording SHM data from inside structural elements. In this paper, a sensor system for embedment into concrete is proposed, able to assess SHM data recorded from concrete. Power is supplied to the sensors on-demand by quadruped robots, which also collect the SHM data via radio-frequency identification (RFID), providing an automated and efficient SHM process. In laboratory experiments, the capability of the sensor system of automatically collecting the SHM data using quadruped robots is validated. In summary, the integration of RFID technology and robot-based inspection presented in this study demonstrates a vital approach to evolve current SHM practices towards more digitalized and automated SHM. T2 - 11th European Workshop On Structural Health Monitoring CY - Potsdam, Germany DA - 10.06.2024 KW - Structural health monitoring KW - RFID-based sensors KW - Smart sensors KW - Embedded sensors KW - Legged robots KW - Quadruped robots PY - 2024 SP - 1 EP - 8 AN - OPUS4-60335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -