TY - JOUR A1 - Hässelbarth, Werner A1 - Daum, Werner A1 - Noack, Siegfried A1 - Subaric-Leitis, Andreas T1 - Ermittlung der Unsicherheit von Prüfergebnissen - Beispiele aus der chemischen Analytik und der Materialprüfung an der BAM (Evaluating the Uncertainty of Test Results - Examples from Chemical Analysis and Materials Testing at BAM) N2 - An der BAM wurde Anfang 1996 die GUM-konforme Ermittlung und Angabe der Unsicherheit quantitativer Prüfergebnisse eingeführt. Nach einem kurzen Überblick über die wesentlichen Schritte und die bisherigen Erfahrungen wird die Ermittlung der Unsicherheit an Beispielen aus zwei Schwerpunktsbereichen der Prüftätigkeit der BAM vorgestellt: atomspektrometrische Analyse anorganischer Materialien und mechanisch-technologische Werkstoffprüfung. Abschließend wird ein Ausblick auf die Ermittlung der Unsicherheit qualitativer Prüfergebnisse gegeben. Diese Arbeit ist ein ergänzender Beitrag zur Thematik des tm-Sonderheftes über GUM-konforme Auswertung von Messungen, das im Januar 2001 erschienen ist. At BAM, GUM-compliant evaluation and expression of uncertainty for quantitative test results was introduced in early 1996. After a brief overview of essential steps and experience so far, uncertainty evaluation is presented for examples from two main fields of BAM´s testing activities: analysis of inorganic materials by atomic spectrometry and mechanical materials testing using tensile/compression testing machines. Finally, an outlook is given on the evaluation of uncertainty for qualitative test results. This paper is a supplementary contribution to the topic of the tm special edition on GUM-compliant evaluation of measurements published January 2001. KW - Messunsicherheit KW - Ergebnisunsicherheit KW - Elementanalytik KW - Kalibrierlösungen KW - Zugprüfung KW - Werkstoffprüfmaschinen PY - 2001 U6 - https://doi.org/10.1524/teme.2001.68.11.519 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 N1 - Sprachen: Deutsch/Englisch - Languages: German/English VL - 68 IS - 11 SP - 519 EP - 528 PB - Oldenbourg CY - München AN - OPUS4-894 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Daum, Werner T1 - Optische Messverfahren - unverzichtbares Instrumentarium in der modernen Materialforschung und -prüfung PY - 2002 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 69 IS - 10 SP - 411 PB - Oldenbourg CY - München AN - OPUS4-1574 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lebid, S. A1 - Habel, Wolfgang A1 - Daum, Werner T1 - How to reliably measure composite-embedded fibre Bragg grating sensors influenced by transverse and point-wise deformations? N2 - Embedded conventional fibre Bragg grating (FBG) sensors with acrylate coating have been chosen for monitoring novel textile-reinforced composite materials with a complicated wavy structure as a result of reinforcing textures. Problems of monitoring this type of material occur due to the harsh fabrication technology of the composite and its complicated structure. Embedded fibre sensors are exposed to the influence of transverse and point-wise deformations. To what extent will these effects influence the measurement signal of a sensor? Temperature cycles, tension and vibration tests were carried out to answer this question. Transverse and point-wise deformation and micromechanical indentation tests on non-embedded FBG sensors were carried out to clarify the reliability of recorded signals. KW - FBG sensors KW - Textile-reinforced composites KW - Measurement reliability PY - 2004 UR - http://www.iop.org/EJ/abstract/0957-0233/15/8/001/ U6 - https://doi.org/10.1088/0957-0233/15/8/001 SN - 0957-0233 SN - 1361-6501 VL - 15 SP - 1441 EP - 1447 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-3846 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Appajaiah, Anilkumar A1 - Wachtendorf, Volker A1 - Daum, Werner T1 - Characterization of thermo-oxidative stability of polymer optical fibers using chemiluminescence technique N2 - The thermo-oxidative stability of commercially available polymer optical fibers (POFs) and their components (cores and claddings) was investigated. All the bare POFs (core and cladding only) studied here were based on poly(methyl methacrylate) (PMMA) core. The fibers were exposed to 100 °C/low humidity for about 4200 h. Chemiluminescence (CL) technique was applied to investigate the thermo-oxidative stability and for measuring the transmission loss during exposure a prototype device called multiplexer was used. POFs exhibited variation in thermo-oxidative stability although they possessed identical core material PMMA. This was due to difference in the chemical compositions of claddings. Claddings were more susceptible to the thermo-oxidative degradation compared to cores. The thermo-oxidative degradation of both the cladding and the core was found in POFs as a result of climatic exposure. POFs showed an early drop-off followed by a slow decline of transmission. The early drop-off of transmission was attributed to physical changes like thermal expansion and the slow decline of transmission to chemical changes like oxidative degradation of POFs. A good linear relationship between optical transmission stability and thermo-oxidative stability of POFs was established from these studies. KW - Polymer optical fibers (POFs) KW - Chemiluminescence (CL) KW - Thermo-oxidative stability KW - Aging KW - Optical transmission stability PY - 2006 U6 - https://doi.org/10.1016/j.polymdegradstab.2006.05.006 SN - 0141-3910 SN - 1873-2321 VL - 91 IS - 11 SP - 2605 EP - 2613 PB - Applied Science Publ. CY - London AN - OPUS4-13984 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Appajaiah, Anilkumar A1 - Wachtendorf, Volker A1 - Daum, Werner T1 - Climatic exposure of polymer optical fibers: Thermooxidative stability characterization by chemiluminescence N2 - The optical transmission stability was investigated for commercially available polymer optical fibers (POFs) which were exposed to a climate of 92°C and 95% relative humidity for about 3300 h. The optical transmission stability of POFs was correlated to their thermooxidative stability. POFs possessed identical core material, poly(methyl methacrylate), but they differed in the materials used for the claddings. The optical transmission was measured online using a prototype device called multiplexer. The chemiluminescence (CL) technique was applied to characterize the thermooxidative stability and degradation of POFs. CL analysis reveals the thermooxidative degradation of bare POFs (core and cladding), predominantly of the claddings, as a result of climatic exposure. Ultraviolet-visible transmittance measurements demonstrated more changes in the claddings as compared to the cores due to degradation. The CL and optical measurements data indicated that the optical transmission stability of POFs was dependent mainly on the thermooxidative stability of the claddings and their chemical compositions. KW - Ageing KW - Polymer optical fiber KW - Degradation KW - Chemiluminescence KW - Transparency PY - 2007 U6 - https://doi.org/10.1002/app.23955 SN - 0021-8995 SN - 1097-4628 VL - 103 IS - 3 SP - 1593 EP - 1601 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-19072 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maiwald, Michael A1 - Daum, Werner T1 - Trends in der prozessanalytischen Messtechnik N2 - Eine gleich bleibend effektive Nutzung von Anlagen, Rohstoffen und Energie in Verbindung mit der optimalen Prozessführung sind die wichtigsten Voraussetzungen für globale Wettbewerbsvorteile der Prozessindustrie. Unternehmen aus den Bereichen Chemie, Pharmazie, Petrochemie, Gasverarbeitung, Lebensmittel-, Zellstoff-, Papier-, Glas-, Stahl- und Zementherstellung sowie ihren Zulieferern haben den Einsatz zuverlässiger Prozessautomation für eine gute Prozessführung erkannt. Überlegene Verfahren stützen sich zunehmend auf prozessanalytische Messtechnik zur Kontrolle und präventiven Sicherstellung der geforderten Produktqualität. Gleichzeitig ermöglicht sie eine ständige Verbesserung des Wissens über den Prozess und erhöhen die Prozess- und Anlagensicherheit. PY - 2011 U6 - https://doi.org/10.1524/teme.2011.9026 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 78 IS - 12 SP - 547 EP - 548 PB - Oldenbourg CY - München AN - OPUS4-25262 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brandes, K. A1 - Neitzel, F. A1 - Weisbrich, S. A1 - Daum, Werner T1 - Lagrange-Multiplikatoren (LM) der Ausgleichsrechnung als Indikator für Strukturschäden N2 - Die ständige Überwachung von Bauwerken gewinnt zunehmend an Bedeutung. Mit Blick auf die Nachhaltigkeit ist die Verlängerung der Nutzungsdauer bestehender baulicher Konstruktionen von unschätzbarem Wert, sowohl aus finanziellen Gründen als auch unter Denkmalaspekten. Eine neue Methode zur Detektion von Strukturschädigungen basiert auf einer integrierten Auswertung von Messwerten verschiedener Sensoren nach der Methode der kleinsten Quadrate sowie der Interpretation der dabei auftretenden Langrange-Multiplikatoren. Diese Methode der Schädigungsanalyse wird anhand eines numerischen Beispiels aus einem Vier-Punkt-Biegeversuch mit einem Verbundträger näher erläutert. --------------------------------------------------------------------------------------------------------- Structural health monitoring of structures is gaining increasingly importance. With regard to sustainability it is of great value for both financial reasons (to extend the useful life of existing architectural structures) and the aspects of listed buildings. A new method for the detection of structural damage is based on an integrated analysis of measurements of different sensors according to the method of least squares and the interpretation of the occurring Lagrange Multipliers. This method of damage analysis is illustrated by a numerical example of a four-point bending test with a composite beam. KW - Bauwerk KW - Schädigung KW - Zustandsüberwachung KW - Schadensfrüherkennung KW - Ausgleichsrechnung KW - Lagrange-Multiplikator KW - Construction KW - Damage KW - Structural health monitoring KW - Damage detection KW - Curve fitting KW - Lagrange multiplier PY - 2012 U6 - https://doi.org/10.1524/teme.2012.0239 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 79 IS - 7-8 SP - 348 EP - 358 PB - Oldenbourg CY - München AN - OPUS4-26385 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Daum, Werner A1 - Werthschützky, R. T1 - Strukturintegrierte Sensorik PY - 2012 U6 - https://doi.org/10.1524/teme.2012.9026 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 79 IS - 7-8 SP - 335 EP - 336 PB - Oldenbourg CY - München AN - OPUS4-26386 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krebber, Katerina A1 - Lenke, Philipp A1 - Liehr, Sascha A1 - Nöther, N. A1 - Wendt, Mario A1 - Wosniok, Aleksander A1 - Daum, Werner T1 - Structural health monitoring by distributed fiber optic sensors embedded into technical textiles N2 - Technical textiles with embedded distributed fiber optic sensors have been developed for the purposes of structural health monitoring in geotechnical and civil engineering. The distributed fiber optic sensors are based on Brillouin scattering in silica optical fibers and OTDR in polymer optical fibers. Such 'smart' technical textiles are used for reinforcement of geotechnical and masonry structures. The embedded fiber optic sensors provide online information about the condition of the structure and about the occurrence and location of any damage or degradation.-------------------------------------------------------------------------------------------------------------------------------------------------------- Technische Textilien mit integrierten faseroptischen Sensoren eröffnen neue Möglichkeiten der Zustandsüberwachung (structural health monitoring) in Geotechnik und Ingenieurbau. Die verteilt messenden Sensoren basieren auf der Brillouin-Streuung in Glasfasern und auf der OTDR in polymeroptischen Fasern. Derartige 'intelligente' technische Textilien werden in erster Line zur Verstärkung von geotechnischen Bauwerken und von Gebäuden genutzt. Die integrierten Sensoren liefern eine zeitnahe Information über den bestimmungsgemäßen Zustand des Bauwerks sowie über die Entstehung und den Ort von lokalen Bauwerksschäden. KW - Fiber optic sensor KW - Distributed sensor KW - Brillouin scattering KW - Polymer optical fiber KW - Strain sensor KW - Smart geotextiles KW - Faseroptischer Sensor KW - Verteilter Sensor KW - Brillouin-Streuung KW - Polymeroptische Faser KW - Dehnungssensor KW - Intelligentes Geotextil PY - 2012 U6 - https://doi.org/10.1524/teme.2012.0238 SN - 0340-837X SN - 0178-2312 SN - 0171-8096 VL - 79 IS - 7-8 SP - 337 EP - 347 PB - Oldenbourg CY - München AN - OPUS4-26387 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Tabea A1 - Bartholmai, Matthias A1 - Daum, Werner ED - Ognjanovic, M. ED - Stankovic, M. ED - Ristic, M. T1 - Introduction in the system of the split Hopkinson pressure bar and validation of the method N2 - 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. T2 - DAS-29 - 29th Danubia-Adria-symposium on advances in experimental mechanics CY - Belgrade, Serbia DA - 2012-09-26 PY - 2012 SN - 978-86-7083-762-1 N1 - Geburtsname von Köppe, Tabea: Wilk, T. - Birth name of Köppe, Tabea: Wilk, T. SP - 52 EP - 53 CY - Belgrade, Serbia AN - OPUS4-26638 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -