TY - GEN A1 - Ziemann, O. A1 - Krauser, J. A1 - Zamzow, P. E. A1 - Daum, Werner T1 - POF handbook - Optical short range transmission systems PY - 2008 SN - 978-3-540-76628-5 U6 - https://doi.org/10.1007/978-3-540-76629-2 SP - 1 EP - 880 PB - Springer CY - Berlin ET - 2. AN - OPUS4-16699 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Richter, Frank A1 - Köppe, Enrico A1 - Daum, Werner T1 - Tracking deformation history in split Hopkinson pressure bar testing N2 - The stress vs. strain curve of materials is affected the rate of imposed straining. Among the methods for dynamic testing the technique known as 'split Hopkinson pressure bar' (SHPB) has evolved into the most widely used one to exert high-speed straining. The theory behind it comprises simple equations to compute stress and strain. The reliability of the strain analysis can be assessed by digital image correlation (DIC). The present results indicate that the visually observed strain is smaller than predicted by theory. T2 - 32nd Danubia-Adria Symposium on advances in experimental mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 KW - Digitale Bildkorrelation (DIC) KW - Dynamische Tests KW - Spannungs-Dehnungs-Kurve KW - Digital image correlation (DIC) KW - Dynamic testing KW - Split Hopkinson pressure bar (SHPB) KW - Stress-strain curve PY - 2016 U6 - https://doi.org/10.1016/j.matpr.2016.03.017 SN - 2214-7853 VL - 3 IS - 4 SP - 1139 EP - 1143 PB - Elsevier CY - Oxford AN - OPUS4-34487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Richter, Frank A1 - Köppe, Enrico A1 - Daum, Werner T1 - Tracking deformation history in split Hopkinson pressure bar testing N2 - The stress vs. strain curve of materials is affected the rate of imposed straining. Among the methods for dynamic testing the technique known as 'split Hopkinson pressure bar' (SHPB) has evolved into the most widely used one to exert high-speed straining. The theory behind it comprises simple equations to compute stress and strain. The reliability of the strain analysis can be assessed by digital image correlation (DIC). The present results indicate that the visually observed strain is smaller than predicted by theory. T2 - 32nd Danubia-Adria Symposium on Advances in Experimental Mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 KW - Split Hopkinson pressure bar (SHPB) KW - Digital image correlation (DIC) KW - Digitale Bildkorrelation (DIC) KW - Dynamic testing KW - Dynamische Tests KW - Stress-strain curve KW - Spannungs-Dehnungs-Kurve PY - 2015 SN - 978-80-554-1094-4 SP - 174 EP - 175 PB - University of Zilina, Slovakia CY - Zilina AN - OPUS4-35656 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Lebid, Solomija A1 - Habel, Wolfgang A1 - Daum, Werner T1 - How reliable measure composite-embedded FBG sensors under the influence of transverse and point-wise deformations? T2 - 16th International Conference on Optical Fiber Sensors (OFS-16) CY - Nara, Japan DA - 2003-10-13 PY - 2003 SN - 4-89114-036-4 SP - 46 EP - 49 PB - IEICE CY - T¯oky¯o AN - OPUS4-2887 LA - eng 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 - CONF A1 - Köppe, Tabea A1 - Daum, Werner T1 - Pulse shaping and alignment tests with the split Hopkinson pressure bar for validation N2 - The Split Hopkinson Pressure Bar (SHPB) is a method for material characterization which works at strain rates from 102 - 104 1/s. This method can be used for example in the field of military engineering, in the field of deformation technology, automobile indurstry, aerospace industry or in other industrial fields. Controlled tests with the SHPB device enable Information about the dynamic material deformaion behaviour in the named strain rate area. The setup of the SHPB is not standarized and the measurement principle is dependent on simplifications. Due to this amongst others the problem with the dispersion of the measurement signal occurs. Furthermore it is possible that measurement uncertainties appear caused by the misalignment of the SHPB setup. In this work the influence of the alignment and a dispersion correction by pulse shaping is presented. On the one side for the alignment calibration tests are done. And on the other side for the dispersion influence correction with pulse shaping tests are done with TiA16V4. This material was choosen due to the fact that it can be compared with existing literature data. T2 - 31st Danubia-Adria Symposium on advances in experimental mechanics CY - Kempten, Germany DA - 24.09.2014 PY - 2014 SN - 978-3-00-046740-0 N1 - Geburtsname von Köppe, Tabea: Wilk, T. - Birth name of Köppe, Tabea: Wilk, T. SP - 242 EP - 243 AN - OPUS4-31730 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 - TY - CONF A1 - Köppe, Enrico A1 - Hofmann, Detlef A1 - Daum, Werner T1 - Absolute measuring EFPI-measurement system N2 - The absolute detection of a gap distance of loose and ftxed extrinsic Fabry-Perot interferometer (EFPI) sensors with conventional measurement Systems is not possible. Due to this EFPI-sensors were deemed to be unfit for distance determination in comparision with FBG sensors. With the conventional measurement method a continous measurement of the EFPIsensors was necessary. Otherwise data about the distance change was lost. Additional it is necessary to detect the tumaround points in the interference signal with 100%. This made it worse for the analysis and the use of the sensor. At BAM Federal Institute for Materials Research and Testing a measurement System called “EFPI-Scan” is developed which can measure the absolute gap distance of four connected EFPI-sensors synchronous. Every measurement channel is temperature independetn and long term stable. Test measurements showed a deviation of maximum ±1 gm per hour. Furthermore it is possible to measure with different measurement modes (abolute, relative and a combination of both). Special emphasis should be placed to the absolute measurement accuracy of ± 5 pm at a gap distance determination ftom 40 up to 4000 pm. T2 - 31st Danubia-Adria Symposium on advances in experimental mechanics CY - Kempten, Germany DA - 24.09.2014 PY - 2014 SN - 978-3-00-046740-0 SP - 120 EP - 121 AN - OPUS4-31729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Daum, Werner A1 - Gong, Xing A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Schukar, Vivien A1 - Westphal, Anja A1 - Sahre, Mario A1 - Beck, Uwe T1 - New self - diagnostic fiber optical sensor technique for structural health monitoring N2 - 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. T2 - 32nd DANUBIA ADRIA SYMPOSIUM on Advances in Experimental Mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 KW - Self-diagnostic fiber optical sensor KW - Magnetostrictive metal coating KW - Magnetic field KW - Fiber bragg grating PY - 2016 U6 - https://doi.org/10.1016/j.matpr.2016.03.038 SN - 2214-7853 VL - 3 IS - 4 SP - 1009 EP - 1013 AN - OPUS4-37131 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Daum, Werner A1 - Gong, Xin A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Schukar, Vivien A1 - Westphal, Anja A1 - Sahre, Mario A1 - Beck, Uwe T1 - New self diagnostic fiber optical sensor technique for structural health monitoring N2 - 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. T2 - 32nd Danubia-Adria Symposium on advances in experimental mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 PY - 2015 SN - 978-80-554-1094-4 SP - 1 EP - 2 CY - Zilina AN - OPUS4-35173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -