TY - RPRT A1 - Klingelhöffer, Hellmuth A1 - Ledworuski, Siegmar A1 - Brookes, Stephan-Peter A1 - May, Thomas T1 - Computer controlled tensile testing according to EN 10002-1 Results of a comparison test programm to validate a proposal for an amendment of the standard N2 - Tensile testing according to EN 10002-1 is one of the basic mechanical tests to characterise the mechanical properties of metallic materials. This testing procedure has been regularly under development for many decades in order to modify and amend it and to bring it up to an up to date standard. Today tensile testing for quality control in metals manufacturing industry is routinely performed automatically with computer controlled testing machines. Due to economical needs of industry proposals were made by a European Standard Committee to amend the standard EN 10002-1. A European research project with the acronym TENSTAND was started to validate the proposed modifications of the tensile testing standard. The work package 4 of the project was to validate the machine control characteristics. A comparison test program was started with ten partners, 4 test piece geometries and 3 test parameters for 6 materials, partly with upper and lower yield strength and partly with 0.2 % proof strength to compare experimental results according to the proposal to modify the standard EN 10002-1. Initially testing in the strain control mode was introduced as well as switching of the control mode to crosshead control 1 and switching of the testing speed at appropriate points during the test. The comparison test was evaluated statistically and scientifically. The following conclusions were derived from the comparison test and summarised as recommendations to the standard committees. The scatter of the material properties were not significantly reduced by introducing the amended testing procedure. Few of the reasons for the continuously observed scattercan be identified as follows: The material properties are observed to be widely dependent on the testing speed. As a consequence the range for the allowed testing speed must be reduced. The closed loop control was not optimised sufficiently in some tests, the use of complicated testing machine software led to misinterpretation of software commands, individual testing equipment and implementation of the tensile testing procedure led also to scatter of the material properties which lay in a range of few percent. This is blurred by the inhomogeneity of the material. T3 - BAM Forschungsberichtreihe - 268 PY - 2005 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-1835 SN - 978-3-86509-318-3 SN - 0938-5533 VL - 268 SP - 1 EP - 44 PB - Wirtschaftsverlag NW CY - Bremerhaven AN - OPUS4-183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Fedelich, Bernard A1 - Kiyak, Yusuf A1 - May, Thomas A1 - Pfennig, Anja ED - Gdoutos, E. T1 - Simulation of crack growth under low cycle fatigue at high temperature in a single crystal superalloy T2 - Fracture of nano and engineering materials and structures T2 - 16th European Conference of Fracture "Fracture of Nano and Engineering Materials and Structures" CY - Alexandroupolis, Greece DA - 2006-07-03 KW - Simulation KW - Experiment KW - Crack growth KW - Low cycle fatigue KW - High temperature KW - Single crystal KW - Superalloy KW - Oxidation PY - 2006 SN - 1-402-04971-4 IS - 900_tra SP - 8 pages PB - Springer CY - Dordrecht AN - OPUS4-12556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Ledworuski, Siegmar A1 - Klingelhöffer, Hellmuth A1 - Brookes, Stephen-Peter A1 - May, Thomas ED - Pohl, M. T1 - Untersuchungen zum automatisierten Zugversuch für die Weiterentwicklung der Norm EN 10002-1 im Rahmen des Europäischen Forschungsprojektes TENSTAND T2 - Tagungsband Werkstoffprüfung : Konstruktion, Qualitätssicherung und Schadensanalyse T2 - Werkstoffprüfung - Konstruktion, Qualitätssicherung und Schadensanalyse CY - Neu-Ulm, Deutschland DA - 2004-11-24 KW - Zugversuch KW - TENSTAND KW - Dehngeschwindigkeit KW - Geschwindigkeitseinfluß KW - EN 10002-1 PY - 2004 SN - 3-88355-337-9 SP - 73 EP - 78 PB - Werkstoff-Informationsges. CY - Frankfurt AN - OPUS4-5608 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kiyak, Yusuf A1 - Fedelich, Bernard A1 - May, Thomas A1 - Pfennig, Anja T1 - Simulation of crack growth under low cycle fatigue at high temperature in a single crystal superalloy JF - Engineering fracture mechanics N2 - Crack growth tests have been performed at 950 °C with Single Edge Notch specimens of the Ni-based single crystal superalloy PWA1483. In particular, several orientations and frequencies have been investigated, thus allowing the assessment of the influence of these parameters on the crack growth rate. In addition, oxidation experiments have been carried out to characterize the kinetics of the outer oxide scale growth at the same temperature. On the other side, crack growth has been simulated with the Finite Element program ABAQUS in real test conditions by the node release technique. The nodes are released according to the measured crack growth rate. The simulation results are compared with the test results on the basis of the computed Crack Tip Opening Displacement (CTOD). For this purpose, the crack is propagated until a stabilized value of the CTOD is obtained. This is usually the case when the crack has crossed the initial plastic zone. The procedure provides an evaluation of the effects of cycle frequency, crystal orientation, plasticity and oxide induced crack closure. KW - Finite element analysis KW - Low cycle fatigue KW - Creep-fatigue KW - Crack growth KW - Nickel-based superalloys PY - 2008 DO - https://doi.org/10.1016/j.engfracmech.2007.08.002 SN - 0013-7944 SN - 1873-7315 VL - 75 IS - 8 SP - 2418 EP - 2443 PB - Elsevier Science CY - Kidlington AN - OPUS4-16690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hübert, Thomas A1 - Boon-Brett, L. A1 - Palmisano, V. A1 - Frigo, G. A1 - Hellstrand, A. A1 - Kiesewetter, O. A1 - May, M. ED - Carcassi, M.N. T1 - Trends in gas sensor development for hydrogen safety T2 - ICHS2013 - 5th International conference on hydrogen safety (Proceedings) N2 - Gas sensors are applied for facilitating the safe use of hydrogen in, for example, fuel cell and hydrogen fuelled vehicles. New sensor developments, aimed at meeting the increasingly stringent performance requirements in emerging applications are presented based on in-house technical developments and a literature study. The strategy of combining different detection principles, i.e. sensors based on electrochemical cells, semiconductors or field effects in combination with thermal conductivity sensor or catalytic combustion elements, in one new measuring system is reported. This extends the dynamic measuring range of the sensor while improving sensor reliability to achieve higher safety integrity through diverse redundancy. The application of new nanoscaled materials, nano wires, carbon tubes and graphene as well as the improvements in electronic components of fieldeffect, resistive-type and optical systems are evaluated in view of key operating parameters such as sensor response time, low energy consumption and low working temperature. T2 - ICHS2013 - 5th International conference on hydrogen safety CY - Brussels, Belgium DA - 09.09.2013 KW - Hydrogen KW - Safety KW - Sensors PY - 2013 SN - 978-2-9601366-0-9 SP - Paper 123, 1 EP - 14 AN - OPUS4-31079 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -