TY - JOUR A1 - Mair, Georg A1 - Becker, Ben A1 - Scherer, Florian T1 - Burst strength of composite cylinders - Assessment of the type of statistical distribution JF - Materials Testing N2 - Faserverbundwerkstoffe (Komposite) zeigen außergewöhnliche Veränderungen ihrer Eigenschaften in Abhängigkeit von der Betriebsdauer. Daraus leitet sich auch die Notwendigkeit ab, eine Methode zu finden, die in der Lage ist, Festigkeiten und Restfestigkeiten von Komposit-Druckbehältern zu ermitteln. Dies kann mittels Lastwechselprüfung oder in anderen Fällen vorzugsweise mittels der langsamen Berstprüfung erfolgen. Für eine aussagekräftige Beschreibung der Festigkeit bedürfen die Ergebnisse beider Prüfverfahren einer statistischen Auswertung. Aber insbesondere die statistische Auswertung der berstbezogenen Festigkeitseigenschaften unterliegt neben der Frage der Stichprobengröße einer großen Unsicherheit mit enormen Folgen. Dies ist die Frage, welche Verteilungsfunktion der Streuung der Festigkeitseigenschaft konservativ zugrundegelegt werden darf. So ist zu untersuchen, ob die Gauߑsche Normalverteilung (NV) die wahre Verteilung richtig beschreibt. Es könnten aber auch andere Funktionen, wie z. B. die Weibull-Verteilung notwendig sein, um eine Überschätzung der Überlebenswahrscheinlichkeit bzw. Zuverlässigkeit in dem interessanten Bereich von einem Ausfall pro 104 bis 108 Druckbehältern zu vermeiden. KW - Composite cylinders KW - Residual strength KW - Sample testing KW - Slow burst test KW - Distribution function KW - Probabilistic KW - Anderson-Darlington-test PY - 2014 SN - 0025-5300 VL - 56 IS - 9 SP - 642 EP - 648 PB - Hanser CY - München AN - OPUS4-31305 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Becker, Ben A1 - Duffner, Eric A1 - John, Sebastian T1 - Composite storage systems for CGH2- systematic improvement of RC&S N2 - Conventional approval requirements exclusively ask for minimum strength values, which have to be met. The probabilistic approach estimates how likely none of the comparatively manufactured units fails during operation. Both questions are juxtaposed and compared here with respect to the load cycle tests. The influence of the sample sizes is discussed additionally. T2 - 10th INTERNATIONAL CONFERENCE ON SUSTAINABLE ENERGY & ENVIRONMENTAL PROTECTION CY - Bled, Slovenia DA - 27.06.2017 KW - Probabilistic KW - Hydrogen KW - Composite KW - Cylinder KW - Regulations KW - Load cycles KW - GTR 13 PY - 2017 AN - OPUS4-41677 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg A1 - Scholz, Irene A1 - Schönfelder, Thorsten T1 - The residual strength of breathing air composite cylinders toward the end of their service life - a first assessment of a real-life sample JF - Journal of pressure vessel technology N2 - Applications by fire brigades expose the composite cylinders to harsh temperature and handling conditions. Standards have been used for certifying composite cylinders, which are designed for transport of dangerous goods and do not reflect service conditions specific to fire brigades. In this paper, the residual safety of a design type (fully wrapped with aluminum and carbon fiber composite) at the end of their service life of 15 yrs is analyzed. One sample underwent hydraulic load cycle (LC) tests, another conventional burst tests, and the third slow burst tests (SBTs). The statistical evaluation and the handling of an unexpected high amount of early failures are shown. KW - Composite cylinders KW - End of life KW - Slow burst test KW - Residual strength KW - Sample testing KW - Probabilistic KW - Distribution function PY - 2016 DO - https://doi.org/10.1115/1.4033878 SN - 0094-9930 SN - 1528-8978 VL - 138 IS - 6 SP - PVT-15-1030, 1 EP - 9 PB - American Society of Mechanical Engineers CY - New York, NY AN - OPUS4-33157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Becker, Ben A1 - Duffner, Eric A1 - John, Sebastian T1 - Storage systems for CGH2- systematic improvement of RC&s composite storage systems for compressed hydrogen - systematic improvement of regulations for more attractive storage units T2 - Conference Proceedings: 10th International Conference on Sustainable Energy and Environmental Protection - Hydrogen and Fuel Cells N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety they have to undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of for on-board storage of hydrogen are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic (UN GTR No. 13) criteria. This paper analysis the properties of such methods in regards to the evaluation of load cycle strength. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations, the available design range (mean value and scatter of strength criteria) of current concepts were exemplarily estimated. The aspect of small sample sizes is analysed and discussed with respect to the evaluation procedures. T2 - 10th International Conference on Sustainable Energy and Environmental Protection CY - Bled, Slovenia DA - 27.06.2017 KW - Probabilistic KW - Hydrogen KW - Composite KW - Cylinder KW - Regulations KW - Load cycles KW - GTR 13 KW - ISO 11119 PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-416820 SN - 978-961-286-054-7 DO - https://doi.org/10.18690/978-961-286-054-7 SP - 1 EP - 10 PB - University of Maribor Press CY - Maribor, Slovenia AN - OPUS4-41682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - BOOK A1 - Mair, Georg T1 - Safety Assessment of Composite Cylinders for Gas Storage by Statistical Methods N2 - Featuring a detailed analysis of current approval requirements and the relevant safety assessment methods for gas cylinders in general and with main focus on composite cylinders for storing ompressed natural gas and hydrogen, this book demonstrates how current regulations and standards limit the ability to reduce cost and weight. Based on this data, it then highlights the potential offered by the proposed approval procedure based on probabilistic safety assessment. After addressing the economic potential of probabilistic safety assessments, the book details working procedures and improving cycles and (slow) bursts as methods for assessing residual strength. It then discusses methods for statistically evaluating test data, as well as sample- size and distribution character considerations. A definition of sample strength is elaborated in terms of the performance sheets developed by the author. On this basis, it discusses safety as a property of service life and interpreted as an issue of degradation, and explores aspects of artificial aging for simulating the end-of-life reliability level. Lastly, the book considers control and inspection aspects: quality of production, degradation prediction using destructive sample tests parallel to operation, retesting periods and correcting for underand overestimates of safe lifetime. Presented in schematic diagrams, illustrations and tables, this information enables manufacturers and operators to use this new approach in practice and supports the improvement of current regulations and standards. KW - Probabilistic KW - Statistics KW - Slow burst testing KW - Fire engulfment KW - Crash loads KW - Degradation KW - Production scatter KW - Operational loads KW - Residual strength KW - Service life KW - Design life KW - Safety KW - Risk KW - Consequences KW - Failure rate KW - Survival rate KW - Confidence level KW - Acceptance rate PY - 2017 SN - 978-3-319-49708-2 SN - 978-3-319-49710-5 DO - https://doi.org/10.1007/978-3-319-49710-5 VL - 2017 SP - I ; 1 EP - XXI; 269 PB - Springer International Publishing CY - Cham, Switzerland ET - 1. AN - OPUS4-42324 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg A1 - Becker, Ben A1 - John, Sebastian A1 - Duffner, Eric T1 - Composite storage systems for compressed hydrogen - systematic improvement of regulations for more attractive storage units JF - International Journal of Hydrogen Energy N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety, they must undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of hydrogen and for its onboard storage are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic (UN GTR No. 13) criteria. This paper analysis the properties of such methods with respect to the evaluation of load cycle strength. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations, the available design range (mean value and scatter of strength criteria) of current concepts was exemplarily estimated. The aspect of small sample sizes is analysed and discussed with respect to the evaluation procedures. KW - Probabilistic KW - Monte-Carlo KW - Regulations KW - Composite cylinder KW - Hydrogen vehicles KW - Transport of dangerous goods PY - 2018 DO - https://doi.org/10.1016/j.ijhydene.2018.04.068 SN - 0360-3199 VL - 45 IS - 25 SP - 13672 EP - 13679 PB - Elsevier Ltd AN - OPUS4-46856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg A1 - Becker, B. A1 - John, Sebastian A1 - Duffner, Eric T1 - Composite storage systems for compressed hydrogen - systematic improvement of regulations for more attractive storage units JF - International Journal of Hydrogen Energy; Special issue on the 10th International Conference on Sustainable Energy and Environmental Protection (SEEP 2017) N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. Forensuring safety, they must undergo a challenging approval process. Relevant standardsand regulations for composite cylinders used for the transport of hydrogen and for its on-board storage are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic(UN GTR No. 13) criteria. This paper analysis the properties of such methods withrespect to the evaluation of load cycle strength. Their characteristics are compared withthe probabilistic approach of the BAM. Based on Monte-Carlo simulations, the availabledesign range (mean value and scatter of strength criteria) of current concepts was exem-plarily estimated. The aspect of small sample sizes is analysed and discussed with respectto the evaluation procedures. KW - Probabilistic KW - Monte-Carlo KW - Regulations KW - Composite cylinder KW - Hydrogen vehicles KW - Transport of dangerous goods PY - 2020 DO - https://doi.org/10.1016/j.ijhydene.2018.04.068 SN - 0360-3199 VL - 45 IS - 25 SP - 13672 EP - 13679 PB - Elsevier Ltd. AN - OPUS4-50687 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -