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Autor

  • Bartholmai, Matthias (21)
  • Neumann, Patrick P. (10)
  • Köppe, Enrico (6)
  • Lazik, D. (6)
  • Johann, Sergej (4)
  • Werner, Klaus-Dieter (4)
  • Basedau, Frank (3)
  • Beck, Uwe (3)
  • Ebert, Sebastian (3)
  • Gong, Xin (3)
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Erscheinungsjahr

  • 2019 (2)
  • 2018 (1)
  • 2017 (1)
  • 2016 (5)
  • 2015 (4)
  • 2014 (3)
  • 2013 (1)
  • 2012 (4)

Dokumenttyp

  • Beitrag zu einem Tagungsband (21) (entfernen)

Referierte Publikation

  • ja (21) (entfernen)

Schlagworte

  • Gas storage areas (3)
  • Membrane-based gas sensing (3)
  • Structural health monitoring (3)
  • Subsurface monitoring (3)
  • Autonomous micro UAV (2)
  • Embedded sensors (2)
  • Gas source localization (2)
  • Wireless sensors (2)
  • Actuators (1)
  • Biologically inspired robots (1)
  • Chemical and wind sensing (1)
  • Computed tomography (1)
  • DDS (1)
  • Distributed linear sensor (1)
  • Distributed sensor (1)
  • Early damage detection (1)
  • Early-damage-detection (1)
  • Embedded system (1)
  • Embedded systems (1)
  • Energy harvesting (1)
  • Fiber Bragg grating (1)
  • Fiber Bragg gratings (1)
  • Fiber optical sensing (1)
  • Fibre optical sensing (1)
  • Field conditions (1)
  • Finite element methods (1)
  • Fluorescent sensor (1)
  • Gas dispersion simulation (1)
  • Guided wave (1)
  • Inertial measurement unit (1)
  • Inertial navigation system (1)
  • Lamb wave (1)
  • Lamb-waves (1)
  • Large scale soil test field (1)
  • Leak detection (1)
  • Linear sensor (1)
  • Magnetic field (1)
  • Magnetostriction (1)
  • Membrane-based linear gas sensor (1)
  • Mobile robot olfaction (1)
  • Modeling and simulation (1)
  • Moisture (1)
  • Monitoring of CO2 (1)
  • Non-destructive evaluation (1)
  • Oil (1)
  • Particle filter (1)
  • Passive sensors (1)
  • Person tracking (1)
  • RFID sensors (1)
  • RFID-based sensors (1)
  • Reactive plume tracking (1)
  • Remote gas sensor model (1)
  • SHM (1)
  • Sensor calibration and validation (1)
  • Soil test field (1)
  • Strain (1)
  • TDLAS (1)
  • Transmission characteristics (1)
  • Ultrasound (1)
  • Water quality (1)
  • Wireless mobile sensor device (1)
  • Wireless sensor network (WSN) (1)
  • agricultural economy (1)
  • embedded sensor (1)
  • environment (1)
  • fluorescence (1)
  • gas analysis (1)
  • spectroscopy (1)
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Organisationseinheit der BAM

  • 8 Zerstörungsfreie Prüfung (13)
  • 8.1 Sensorik, mess- und prüftechnische Verfahren (13)
  • 6 Materialchemie (3)
  • 1 Analytische Chemie; Referenzmaterialien (2)
  • 1.9 Chemische und optische Sensorik (2)
  • 6.7 Oberflächenmodifizierung und -messtechnik (2)
  • 8.2 Zerstörungsfreie Prüfmethoden für das Bauwesen (2)
  • 8.6 Faseroptische Sensorik (2)
  • 6.0 Abteilungsleitung und andere (1)
  • 7 Bauwerkssicherheit (1)
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Device concept for the generation of guided waves for early damage detection (2012)
Köppe, Enrico ; Bartholmai, Matthias ; Prager, Jens
In this study a method for early damage detection is investigated based on the directed excitation and measuring of Lamb waves (guided waves). The objective is to make a statement about the practicability of a Lamb wave generator (LWG) and about the application relevant parameters (specimen materials and dimensions, wave characteristics, excitation, transmission und reflection). Guided waves enable an effective differentiation of structural and defective indications as well as a classification of different defect types. For the investigations, a LWG was developed which combines the advantages of the single excitation of a piezoelectric actuator and the possibility of a group excitation. Algorithms were developed to identify and analyze damage patterns (cracks, wholes, weakening).
Early damage detection of structural defects using guided waves (2012)
Bartholmai, Matthias ; Köppe, Enrico ; Prager, Jens
Limited access to the object of relevance is often an essential problem in testing routines, e.g. for non-destructive testing of industry facilities or components of means of transportation. The presented project is about the development of a non-destructive testing method for application over great distances (up to 100 m). The method is based on directed excitation and measuring of Lamb waves (guided waves). It enables an effective differentiation of structural and defective indications as well as a classification of different defect types. The advantage of guided waves is the ability of propagation over great distances. This offers innovative possibilities for the investigation of large or difficult to access constructions. The testing method can be helpful in a broad variety of applications. It is useable for the characterization of plane or cylindrical, thin-walled surfaces of metal or fiber laminated materials. Particularly the investigation of aircraft wings and other aerospace components as well as the investigation of pipelines are addressed fields of application.
Radio-based multi-sensor system for person tracking and indoor positioning (2012)
Köppe, Enrico ; Bartholmai, Matthias ; Liers, A. ; Schiller, J.
Sensor based person tracking is a challenging topic. The main objective is positioning in areas without GPS connection, i.e. indoors. A research project is carried out at BAM, Federal Institute for Materials Research and Testing, to develop and to validate a multi-sensor system for 3D localization. It combines body motion sensing and a guard system for the tracking and recording of the status of persons. The so named BodyGuard system was designed for sensor-based monitoring and radio-based transmission of the movement of a person. Algorithms were developed to transform the sensor data into a spatial coordinate. This paper describes how the BodyGuard system operates, which main components were used in the system, how the individual sensor data are converted into 3D motion data, with which algorithms the individual sensors are processed, how individual errors are compensated and how the sensor data are merged into a 3D Model. Final objective of the BodyGuard system is to determine the exact location of a person in a building, e.g. during fire-fighting operations.
From insects to micro air vehicles - a comparison of reactive plume tracking strategies (2016)
Neumann, Patrick P. ; Bennetts, V.H. ; Lilienthal, A.J. ; Bartholmai, Matthias
Insect behavior is a common source of inspiration for roboticists and computer scientists when designing gas-sensitive mobile robots. More specifically, tracking airborne odor plumes, and localization of distant gas sources are abilities that suit practical applications such as leak localization and emission monitoring. Gas sensing with mobile robots has been mostly addressed with ground-based platforms and under simplified conditions and thus, there exist a significant gap between the outstanding insect abilities and state-of-the-art robotics systems. As a step toward practical applications, we evaluated the performance of three biologically inspired plume tracking algorithms. The evaluation is carried out not only with computer simulations, but also with real-world experiments in which, a quadrocopter-based micro Unmanned Aerial Vehicle autonomously follows a methane trail toward the emitting source. Compared to ground robots, micro UAVs bring several advantages such as their superior steering capabilities and fewer mobility restrictions in complex terrains. The experimental evaluation shows that, under certain environmental conditions, insect like behavior in gas-sensitive UAVs is feasible in real-world environments.
Near real-time reconstruction of 2D soil gas distribution from a regular network of linear gas sensors (2015)
Neumann, Patrick P. ; Bartholmai, Matthias ; Lazik, D.
A monitoring method is introduced that creates, in near real-time, two-dimensional (2D) maps of the soil gas distribution. The method combines linear gas sensing technology for in-situ monitoring of gases in soil with the mapping capabilities of Computed Tomography (CT) to reconstruct spatial and temporal resolved gas distribution maps. A weighted iterative algebraic reconstruction method based on Maximum Likelihood with Expectation Maximization (MLEM) in combination with a source-by-source reconstruction approach is introduced that works with a sparse setup of orthogonally-aligned linear gas sensors. The reconstruction method successfully reduces artifact production, especially when multiple gas sources are present, allowing the discrimination between true and non-existing so-called ghost source locations. A first experimental test indicates the high potential of the proposed method for, e.g., rapid gas leak localization.
Concept for investigating mechanical impacts on distributed subsurface gas monitoring (2015)
Petrov, Sergej ; Neumann, Patrick P. ; Werner, Klaus-Dieter ; Lazik, D. ; Bartholmai, Matthias
A multifunctional sensor in line shape was developed and introduced in previous work for measuring of gas concentrations, temperature change, and strain. A current field study focuses on a spatially distributed monitoring of subsurface CO2 gas storage sites in near real time. Mechanical impacts, e.g., caused by construction work, denudation, and seismic activity, can affect the integrity of underground gas storage sites. Thermal or moisture impacts, e.g., caused by weather conditions, can influence the gas distribution behavior. In this paper, we briefly describe the setup of a CO2 injection soil test field. This setup contains actuating elements for the investigation of mechanical and thermal impacts on distributed subsurface gas monitoring. A concept is given for evaluating these impacts and first experimental results are presented.
Inverse calibration routine for linear soil gas sensors (2015)
Neumann, Patrick P. ; Ebert, Sebastian ; Lazik, D. ; Bartholmai, Matthias
Gas sensors in linear form based on the measuring principle of gas selective permeability through a membrane were developed and introduced for the detection and quantification of gas concentrations. A current field study focuses on measuring CO2 concentrations for a spatially distributed monitoring of subsurface CO2 gas storage sites in near real time. A 400 m(2) test site and a corresponding laboratory system were built up to characterize, validate, and optimize the sensor. A calibration routine was developed, which can be applied subsequently to underground installation. First measurement results indicate the potential of the method.
A probabilistic gas patch path prediction approach for airborne gas ource localization in non-uniform wind fields (2013)
Neumann, Patrick P. ; Schnürmacher, M. ; Bennetts, V.H. ; Lilienthal, A.J. ; Bartholmai, Matthias ; Schiller, J.H.
In this paper, we show that a micro unmanned aerial vehicle (UAV) equipped with commercially available gas sensors can address environmental monitoring and gas source localization (GSL) tasks. To account for the challenges of gas sensing under real-world conditions, we present a probabilistic approach for GSL that is based on a particle filter (PF). Simulation and real-world experiments demonstrate the suitability of this algorithm for micro UAV platforms.
Embedded passive RFID-based sensors for moisture monitoring in concrete (2017)
Strangfeld, Christoph ; Johann, Sergej ; Müller, Maximilian ; Bartholmai, Matthias
Damages in infrastructure due to moisture amount to billions of Euros every year. For a more predictive structural health monitoring in civil engineering, the detection and monitoring of hazardous moisture in steel reinforced concrete constructions is of high interest. The sensors have to be wireless, elsewise they weaken the concrete cover of the rebars. The lifetime of such constructions is normally decades, thus the sensors have to be battery-free and fully passive. Considering these requirements, passive RFID-based sensors are developed. Communication and energy supply are realized wireless via the electromagnetic field of a RFID transmitter. The passive RFIDbased sensors are embedded into the concrete to enable the monitoring of moisture transport in porous materials. Results of the hydration process are shown.
Wireless Mobile Sensor Device for in-situ Measurements with Multiple Fluorescent Sensors (2018)
Johann, Sergej ; Mansurova, Maria ; Kohlhoff, Harald ; Gkertsos, Aris ; Neumann, Patrick P. ; Bell, Jérémy ; Bartholmai, Matthias
This paper describes a wireless mobile prototype able to perform optical measurements by means of a miniatur-ized spectrometer for low light analysis, e.g. fluorescent sensors. Evaluations, calculations, calibration management and result display are performed by a computer or a standard tablet. The device was designed primarily to detect traces of oil in drinking or ground water and for the analyses of crude oils. However, it can also address a wide range of fluorescent sensors. The fast and user-friendly inspection of water quality or oil properties, as well as the adaptability and mobility, make the device attractive for a variety of users. Further application areas could be easily imple-mented by adapting the optics and the software (database, data processing and calibration plots, etc.)
Modelling and simulation of a fibre Bragg grating strain sensor based on a magnetostrictive actuator principle (2016)
Schukar, Vivien ; Gong, Xin ; Hofmann, Detlef ; Basedau, Frank ; Köppe, Enrico ; Bartholmai, Matthias ; Westphal, Anja ; Sahre, Mario ; Beck, Uwe
A new concept for the self-diagnosis of embedded fiber Bragg grating (FBG) strain sensors was developed, simulated and experimentally tested. This concept is based on a magnetostrictive metallic layer directly coated on the fibre cladding over the grating segment of the FBG sensor, so that an on-demand external magnetic field in a millitesla scale can produce a controllable artificial strain as an indication signal for the remote optical interrogator. The relationship between the pre-defined magnetic field and its induced Bragg wavelength shift characterizes this validation concept. Any deviation of the local bonding state of the interfaces from the initial or/and any change of shear strain transferring mechanism from composite matrix to the optical fibre core will result in alterations in this sensitive relationship, and thus triggers an immediate alert for a further inspection. The finite element method is used to simulate the strain of this configuration as result of different values of the magnetic field in order to optimize the geometrical sensor parameters. The simulations are verified by experiments results. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Transmission characteristics of RFID sensor systems embedded in concrete (2016)
Bartholmai, Matthias ; Johann, Sergej ; Kammermeier, Michael ; Müller, Maximilian ; Strangfeld, Christoph
Completely embedded sensor systems for long-term operation offer innovative possibilities for structural health monitoring of concrete structures. Measuring of relevant parameters, e.g., temperature, humidity, or indication of corrosion can be performed with low energy sensors. This allows to implement passive RFID sensor systems without cable connection and battery, which are power supplied exclusively by the electromagnetic field from the external reader device. To evaluate characteristics and conditions of this concept, a systematical investigation of the transmission characteristics with variation of relevant parameters, as communication frequency, installation depth, type of concrete, moisture content, etc. is currently carried out in an interdisciplinary research project at BAM. First results are presented in this paper.
New self diagnostic fiber optical sensor technique for structural health monitoring (2015)
Köppe, Enrico ; Bartholmai, Matthias ; Daum, Werner ; Gong, Xin ; Hofmann, Detlef ; Basedau, Frank ; Schukar, Vivien ; Westphal, Anja ; Sahre, Mario ; Beck, Uwe
Fiber optic sensors have gained increasing importance in recent years and are well established in many areas of industrial applications. In this paper, we introduce a concept of a self-diagnostic fiber optic sensor. The presented sensor is to resolve the problems of embedded fiber optic sensors in complex structures and to enable the validation under operational conditions. For this purpose, different magnetostrictive coated fiber optic sensors were developed and various experiments were performed to verify their mode of operation and to determine the respective reproducibility. The measuring principle is illustrated by obtained experimental results, which showed a change in wavelength from 1 pm at a magnetic field strength change of 0.25 mT. In addition, the temperature characteristics of the implemented magnetostrictive sensor were analyzed and an experimental factor of 1.5 compared to a reference fiber optic sensor was determined.
Introduction in the system of the split Hopkinson pressure bar and validation of the method (2012)
Köppe, Tabea ; Bartholmai, Matthias ; Daum, Werner
The Split Hopkinson Pressure Bar (SHPB) or Kolsky Bar is known as a method for analysing mechanical properties of a material under dynamic load. Referring to the name it is a splitted Hopkinson Pressure Bar. The Hopkinson Bar is related to its inventor Bertram Hopkinson (1914). He used it to analyze stone samples under dynamic load. Later his construction was improved by Davies (1948) [1] and Kolsky (1949) [2], who had the idea to split the bar and put a sample in between. The technique is used to measure a lot of different mechanical properties of a material e.g. the dynamic Young’s modulus, deformation behaviour or to chart the dynamic stress-strain diagram. Further applications are the measurement of the elastic wave and the analysis of the propagation of the wave [2]. In the last years there was still an interest in measuring dynamic properties with a SHPB. Nevertheless no comprehensive validation of the system exists. Another problem is that the stress and the strain in the sample are only calculated with simplified estimations. The aim of this paper is to give a first impression of important points validating the system. On account of different setups of the SHPB a validation of the used system is necessary. Hence it is important to look at the theory. Further in this paper the measurement results will be shown in a strain over time diagram.
Semi-automatic Gas Measurement Device Based on Fluorescent Multi-gas Sensors (2019)
Johann, Sergej ; Kohlhoff, Harald ; Gawlitza, Kornelia ; Bell, Jérémy ; Mansurova, Maria ; Tiebe, Carlo ; Bartholmai, Matthias
This paper describes the development of a semi-automatic gas measurement device presenting potentially a broad range of applications, noteworthy in the agricultural sector. Non-reversible fluorescent molecular sensors were designed and syn-thesized. Upon, integration into a hydrogel matrix with an optimal ratio of co-solvents, the sensors reacting selectively to ammonia were illuminated by excitation light to produce a concentration-correlated fluorescence emission. An automated mechanical-elec-trical device initiates a given gas mixture and thus simulates con-centrations similar to a threshold value. The aim of this project is to develop a sensor or a low-cost method which can monitor low concentrations of harmful gases and aid in their elimination or regulation in livestock housing, barns or stables.
Experimental Validation of the Cone-Shaped Remote Gas Sensor Model (2019)
Hüllmann, Dino ; Neumann, Patrick P. ; Scheuschner, Nils ; Bartholmai, Matthias ; Lilienthal, A.J.
Remote gas sensors mounted on mobile robots enable the mapping of gas distributions in large or hardly accessible areas. A challenging task, however, is the generation of threedimensional distribution maps from these gas measurements. Suitable reconstruction algorithms can be adapted, for instance, from the field of computed tomography (CT), but both their performance and strategies for selecting optimal measuring poses must be evaluated. For this purpose simulations are used, since, in contrast to field tests, they allow repeatable conditions. Although several simulation tools exist, they lack realistic models of remote gas sensors. Recently, we introduced a model for a Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor taking into account the conical shape of its laser beam. However, the novel model has not yet been validated with experiments. In this paper, we compare our model with a real sensor device and show that the assumptions made hold.
Magnetic field detection with an advanced FBG-based sensor device (2016)
Schukar, Vivien ; Köppe, Enrico ; Hofmann, Detlef ; Westphal, Anja ; Sahre, Mario ; Gong, Xin ; Bartholmai, Matthias ; Beck, Uwe
A high-performance fiber Bragg grating-based (FBG) sensor device has been developed for the detection of small magnetic fields. Based on a smart multilayer jacket around the fibre over the physical length of the FBG, magnetic fields generated by rotating machine parts, power generators or power cable can be easily detected, analysed and evaluated. Consequently, this innovative, on-line and non-contact inspection method results in an increase in quality and reliability of high-performing machine parts, devices and cables. The basic physical principle is based on a magnetostrictive multilayer system that strains the high-resolution FBG element in presence of magnetic fields. Subsequently, a fixed relationship between induced magnetic field and wavelength change of the FBG element describes the characteristic sensitivity curve. Intensive tests regarding characterisation of this magnetic field FBG sensor have been carried out and its performance has been evaluated.
Setup of a large scale soil test field with CO2 injection for testing a novel distributed subsurface monitoring system for gas storage areas (2014)
Neumann, Patrick P. ; Kohlhoff, Harald ; Werner, Klaus-Dieter ; Erdmann, Jessica ; Eggeringhaus, Bärbel ; Kammermeier, Michael ; Schukar, Marcus ; Basedau, Frank ; Bartholmai, Matthias ; Lazik, D. ; Ebert, Sebastian
One of the main unsolved issues of under-ground storages for, e.g., CO2, H2, and natural gas is the comprehensive surveillance of these areas with reasonable effort and costs. Conventional sensors (e.g., soil air probes or borehole probes), however, can only be used for punctual or locally limited measurements; further their application can cause structural influences (invasive application). In this paper, we describe in detail the setup of a CO2 injection soil test field. This test field will be used to enhance and validate an innovative ap-proach for distributed subsurface monitoring of gas storage areas. To the author’s knowledge, this is the first time that, for this purpose, a test field is built in an application relevant scale.
Hopkinson bar method for temperature dependent testing and calibration of accelerometers (2014)
Bartholmai, Matthias ; Werner, Klaus-Dieter ; Kammermeier, Michael
The measurement characteristics of every conventional accelerometer are temperature dependent - often to an extent which is highly relevant for the addressed application. For instance, at BAM Container drop tests are performed to investigate and evaluate the structural integrity of Containers for transport and storage of dangerous goods. Often, the test program includes drop tests at specific temperatures, also as part of approval procedures. The applied sensors are exposed to these test conditions and get influenced by them. Acceleration sensors show a considerable temperature influence on their fünction and characteristics. Particularly the damping mechanism of the seismic mass is a critical part. In regard to such applications, capable equipment and methods are required to consider and investigate this aspect in an adequate way. A fortiori as Manufacturer’s infonnation often is deficient. This study presents the setup and results of a method for testing and calibration of acceleration sensors under high dynamic irnpact. It combines a Hopkinson Bar with a temperature chamber.
Linear sensor for areal subsurface gas monitoring - calibration routine and validation experiments (2014)
Bartholmai, Matthias ; Neumann, Patrick P. ; Werner, Klaus-Dieter ; Ebert, Sebastian ; Lazik, D.
Membrane based linear gas sensors and fiber optical sensors feature similar geometries and complement each other in quantities to be measured. To the author's best knowledge, it is the first time that these sensors are combined to a multifunctional sensor for distributed measuring of gas concentrations, temperature, and strain. Objective is a comprehensive monitoring of underground gas storage areas. In the presented project a 400 m² test site and a corresponding laboratory system were just built up to characterize, validate, and optimize the combined sensor. Application of the sensor lines in a grid structure should enable spatial resolution of the measurement data and early detection of relevant events, as gas leakage, temperature change, or mechanical impact. A Calibration routine was developed which can be applied subsequent to underground installation. First measurement results indicate the potential of the method, with regard to highly topical energy transport and storage issues.
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