TY - JOUR A1 - Kohlhoff, Harald A1 - Knapp, Jürgen T1 - Pneumatischer Schrittmotor für EMV-Tests KW - EMV-Prüfung PY - 2000 SN - 0177-7297 VL - 36 IS - 9 SP - 52 EP - 54 PB - b-Quadrat-Verl.-GmbH CY - Kaufering AN - OPUS4-905 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ullner, Christian A1 - Reimann, E. A1 - Kohlhoff, Harald A1 - Subaric-Leitis, Andreas T1 - Effect and measurement of the machine compliance in the macro range of instrumented indentation test N2 - The contribution concerns the strong effect of the machine compliance in the upper macro range of the instrumented indentation test on hard materials. To achieve a minimum uncertainty in determination of the machine compliance the measurement and analysis needed for the determination are studied in detail. Based on the assumption that the hardness and/or the indentation modulus are force independent, four methods on the determination of the machine compliance are described. Experimental results of a commercial testing machine up to 2500 N and of a standard machine up to 200 N are analyzed. The results show that the uncertainty of the compliance is usually higher than requested for a precisely enough determination of hardness and further materials parameters. Especially for the calibration of reference materials with high hardness and/or Young’s modulus, the machine compliance should be limited in ISO 14577 part 3, 2003 [1]. KW - Instrumented indentation test KW - Compliance KW - Uncertainty PY - 2010 U6 - https://doi.org/10.1016/j.measurement.2009.09.009 SN - 0263-2241 SN - 1873-412X VL - 43 IS - 2 SP - 216 EP - 222 PB - The Institute of Measurement and Control CY - London AN - OPUS4-20671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wu, Cheng-Chieh A1 - Weisbrich, S. A1 - Neitzel, F. A1 - Kadoke, Daniel A1 - Fischer, Michael A1 - Kohlhoff, Harald ED - Pastramă, Ştefan Dan ED - Constantinescu, Dan Mihai T1 - A Small-Scale Test Bridge for Measurement and Model-based Structural Analysis N2 - The Measurement- and Model-based Structural Analysis (MeMoS) integrates a finite element model into least squares adjustment and thus allows to evaluate a mechanical model and measurements in a combined analysis. To examine the capability to detect and localise damage using this integrated analysis MeMoS, a small-scale truss bridge made of aluminium profiles is built as a test specimen for this purpose. T2 - 35th Danubia Adria Symposium on Advances in Experimental Mechanics CY - Sinaia, Romania DA - 25.09.2018 KW - Structural analysis KW - Damage detection and localisation KW - Finite element method KW - Photogrammetry KW - Adjustment calculation PY - 2019 UR - http://www.sciencedirect.com/science/article/pii/S2214785319304894 U6 - https://doi.org/10.1016/j.matpr.2019.03.130 SN - 2214-7853 VL - 12 IS - 2 SP - 319 EP - 328 PB - Elsevier Ltd. AN - OPUS4-48053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Neumann, Patrick P. A1 - Kohlhoff, Harald A1 - Hüllmann, Dino A1 - Krentel, Daniel A1 - Kluge, Martin A1 - Dzierliński, M. A1 - Lilienthal, A. J. A1 - Bartholmai, Matthias T1 - Aerial-based gas tomography – from single beams to complex gas distributions N2 - In this paper, we present and validate the concept of an autonomous aerial robot to reconstruct tomographic 2D slices of gas plumes in outdoor environments. Our platform, the so-called Unmanned Aerial Vehicle for Remote Gas Sensing (UAV-REGAS), combines a lightweight Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor with a 3-axis aerial stabilization gimbal for aiming at a versatile octocopter. While the TDLAS sensor provides integral gas concentration measurements, it does not measure the distance traveled by the laser diode’s beam nor the distribution of gas along the optical path. Thus, we complement the set-up with a laser rangefinder and apply principles of Computed Tomography (CT) to create a model of the spatial gas distribution from a set of integral concentration measurements. To allow for a fundamental ground truth evaluation of the applied gas tomography algorithm, we set up a unique outdoor test environment based on two 3D ultrasonic anemometers and a distributed array of 10 infrared gas transmitters. We present results showing its performance characteristics and 2D plume reconstruction capabilities under realistic conditions. The proposed system can be deployed in scenarios that cannot be addressed by currently available robots and thus constitutes a significant step forward for the field of Mobile Robot Olfaction (MRO). KW - Aerial robot olfaction KW - Mobile robot olfaction KW - Gas tomography KW - TDLAS KW - Plume PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-487843 SP - 1 EP - 16 PB - Taylor & Francis CY - London AN - OPUS4-48784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüllmann, Dino A1 - Kohlhoff, Harald A1 - Erdmann, Jessica A1 - Neumann, Patrick P. ED - Pastramă, Ş. D. ED - Constantinescu, D. M. T1 - Control of a spherical parallel manipulator N2 - In mobile robot applications, some sensors such as open-path gas detectors or laser rangefinders need to be aimed at specific targets in order to get the desired measurements. To do this in a fast and elegant manner, we present a spherical parallel manipulator with three degrees of freedom. Compared to typical serial manipulators, it offers superior dynamics and structural stiffness, which are important parameters for this type of task. We present the mechanical design and derive kinematic equations both to compute set-points for the desired orientation and to estimate the current state of the system. A PID controller is used to generate control signals. T2 - 35th Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Sinaia, Romania DA - 25.09.2018 KW - Spherical parallel manipulator KW - Sensor orientation KW - Sensor alignment KW - Sensor aiming PY - 2019 U6 - https://doi.org/10.1016/j.matpr.2019.03.145 SN - 2214-7853 VL - 12 IS - 2 SP - 423 EP - 430 PB - Elsevier CY - Amsterdam, Netherlands AN - OPUS4-48044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüllmann, Dino A1 - Paul, Niels A1 - Kohlhoff, Harald A1 - Neumann, Patrick P. A1 - Lilienthal, A. J. ED - Eberhardsteiner, J. ED - Růžička, M. ED - Cosmi, F. T1 - Measuring rotor speed for wind vector estimation on multirotor aircraft N2 - For several applications involving multirotor aircraft, it is crucial to know both the direction and speed of the ambient wind. In this paper, an approach to wind vector estimation based on an equilibrium of the principal forces acting on the aircraft is shown. As the thrust force generated by the rotors depends on their rotational speed, a sensor to measure this quantity is required. Two concepts for such a sensor are presented: One is based on tapping the signal carrying the speed setpoint for the motor controllers, the other one uses phototransistors placed underneath the rotor blades. While some complications were encountered with the first approach, the second yields accurate measurement data. This is shown by an experiment comparing the proposed speed sensor to a commercial non-contact tachometer. T2 - 34th Danubia Adria Symposium on Advances in Experimental Mechanics CY - Trieste, Italy DA - 19.09.2017 KW - Wind vector estimation KW - Rotor speed KW - UAV KW - Tachometer PY - 2018 UR - https://www.sciencedirect.com/science/article/pii/S2214785318321114 U6 - https://doi.org/10.1016/j.matpr.2018.08.139 SN - 2214-7853 VL - 5 IS - 13 SP - 26703 EP - 26708 PB - Elsevier CY - Amsterdam, Netherlands AN - OPUS4-47097 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hüllmann, Dino A1 - Kohlhoff, Harald A1 - Erdmann, Jessica A1 - Neumann, Patrick P. ED - Emri, Igor T1 - Current-independent torque control of permanent-magnet synchronous motors N2 - A current-independent torque equation for the permanent-magnet synchronous motor (PMSM) aiming at direct-drive servo applications is derived from a first principles model. Instead of measuring currents, all required control parameters are derived from optical incremental encoder measurements. The results are verified on a real system in test series showing the effect of static friction and proving the obtained torque model. T2 - 33rd Danubia Adria Symposium on Advances in Experimental Mechanics CY - Portorož, Slovenia DA - 20.09.2016 KW - BLDC KW - Motor control KW - PMSM KW - Servo drive PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S2214785317308271 U6 - https://doi.org/10.1016/j.matpr.2017.06.052 SN - 2214-7853 VL - 4 IS - 5 SP - 5821 EP - 5826 PB - Elsevier CY - Amsterdam, Netherlands AN - OPUS4-41580 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mansurova, Maria A1 - Johann, Sergej A1 - Kohlhoff, Harald A1 - Rurack, Knut A1 - Bartholmai, Matthias A1 - Bell, Jérémy T1 - On-Site Analytical Tool Based on Crude Oil Fluorescence and Chemometrics for the Rapid Determination of the Nature and Essential Properties of Oil Spills N2 - With the reduction of large oil spills because of stricter regulations and safety measures, the question of how to manage smaller oil spills arises. Few on-site analytical tools are available for first responders or other law enforcement personnel to rapidly test for crude oil in the early management of localized polluted areas. The approach reported here relies on well-described computer-assisted multivariate data analysis of the intrinsic fluorescence fingerprints of crude oils to build a multivariate model for the rapid classification of crude oils and the prediction of their properties. Thanks to a dedicated robust portable reader, the method allowed classification and accurate prediction of various properties of crude oil samples like density (according to API, the American Petroleum Institute and viscosity as well as composition parameters such as volume fractions of paraffins or aromatics. In this way, autonomous operation in on-site or in-the-field applications becomes possible based on the direct (undiluted and untreated) measurement of samples and a rapid, tablet-operated readout system to yield a robust and simple analytical test with superior performance. Testing in real-life scenarios allowed the successful classification and prediction of a number of oil spill samples as well as weathered samples that closely resemble samples collected by first responders. KW - Oil spills KW - Fluorescence KW - PCA KW - Petroleum KW - Rapid test KW - Portable PY - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-595442 VL - 4 IS - 2 SP - 621 EP - 627 PB - American Chemical Society (ACS) AN - OPUS4-59544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tschirschwitz, Rico A1 - Krentel, Daniel A1 - Kluge, Martin A1 - Askar, Enis A1 - Habib, Abdel Karim A1 - Kohlhoff, Harald A1 - Krüger, Simone A1 - Neumann, Patrick P. A1 - Rudolph, Michael A1 - Schoppa, André A1 - Storm, Sven-Uwe A1 - Szczepaniak, Mariusz T1 - Experimental investigation of consequences of LPG vehicle tank failure under fire conditions N2 - In case of a vehicle fire, an installed LPG (liquefied petroleum gas) tank with a malfunctioning safety device poses severe hazards. To investigate the consequences in case of tank failure, we conducted 16 tests with toroidal shaped LPG vehicle tanks. Three tanks were used for a Hydraulic Burst Test under standard conditions. Another three tanks were equipped with a statutory safety device and were subjected to a gasoline pool fire. The safety device prevented tank failure, as intended. To generate a statistically valid dataset on tank failure, ten tanks without safety devices were exposed to a gasoline pool fire. Five tanks were filled to a level of 20 %; the re-maining five were filled to a level of 100 %. In order to gain information on the heating process, three tem-perature readings at the tank surface, and three nearby flame temperatures were recorded. At distances of l = (7; 9; 11) m to the tank, the overpressure of the shock wave induced by the tank failure and the unsteady tem-peratures were measured. All ten tanks failed within a time of t < 5 min in a BLEVE (boiling liquid expanding vapor explosion). Seven of these resulted directly in a catastrophic failure. The other three resulted in partial failure followed by catastrophic failure. A near field overpressure at a distance of l = 7 m of up to p = 0.27 bar was measured. All ten tests showed massive fragmentation of the tank mantle. In total, 50 fragments were found. These 50 fragments make-up 88.6 % of the original tank mass. Each fragment was georeferenced and weighed. Fragment throwing distances of l > 250 m occurred. For the tanks with a fill level of 20 %, the average number of fragments was twice as high as it was for the tanks that were filled completely. KW - Blast wave KW - BLEVE KW - Consequences KW - Explosion KW - LPG PY - 2018 UR - https://authors.elsevier.com/a/1XnFv_Ld32ewKu U6 - https://doi.org/10.1016/j.jlp.2018.09.006 SN - 0950-4230 VL - 56 SP - 278 EP - 288 PB - Elsevier CY - Kidlington - Oxford AN - OPUS4-46238 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krentel, Daniel A1 - Tschirschwitz, Rico A1 - Kluge, Martin A1 - Askar, Enis A1 - Habib, Abdel Karim A1 - Kohlhoff, Harald A1 - Mair, Georg A1 - Neumann, Patrick P. A1 - Rudolph, Michael A1 - Schoppa, André A1 - Storm, Sven-Uwe A1 - Szczepaniak, Mariusz T1 - Auswirkungen von unfallbedingtem Behälterversagen bei alternativen Pkw-Antrieben - Teil 1: Problemstellung, Stand der Technik und Voruntersuchungen N2 - Flüssige und komprimierte Gase sind in Deutschland, Europa und der Welt vielfältig als alternative Kraftstoffe im Einsatz. Diese werden unter teilweise hohem Druck in robusten Behältern an Bord gespeichert. Ein Versagen des Treibstoffbehälters im Schadensfall sollen verschiedene Sicherheitseinrichtungen, auch bei einem eventuell unfallbedingt auftretenden Fahrzeugbrand, verhindern. Sind diese Sicherheitseinrichtungen unfallbedingt beschädigt oder liegen die Belastungen dieser Einrichtung außerhalb ihres Auslegungsbereichs, ist ein Versagen des Behälters dennoch möglich. Dadurch kann es zur Bildung eines explosionsfähigen Brennstoff-Luft-Gemischs mit den entsprechenden Folgen für Fahrgäste, Einsatzkräfte und Umfeld kommen. Die Bundesanstalt für Materialforschung und -prüfung (BAM) untersucht im Forschungsprojekt "CoFi-ABV" mit umfangreichen zerstörenden Versuchsreihen im Realmaßstab die Folgen des unfallbedingten Versagens von Behältern für alternative Kraftstoffe und Maßnahmen zur Reduktion dieser Folgen im Rahmen einer ganzheitlichen Auswirkungsbetrachtung. Dieser Beitrag ist der Start einer Reihe und soll die Problemstellung sowie die Projektinhalte umfassend erläutern. KW - Alternative Antriebe KW - Alternative Kraftstoffe KW - Behälterversagen KW - Fahrzeugbrand PY - 2016 SN - 2191-0073 VL - 6 IS - 9 SP - 39 EP - 46 PB - Springer-VDI-Verlag CY - Düsseldorf AN - OPUS4-37360 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -