TY - GEN A1 - Bohse, Jürgen A1 - Mair, Georg A1 - Novak, Pavel ED - Pullin, R. ED - Holford, M. T1 - Acoustic emission testing of high-pressure composite cylinders T2 - Acoustic emission testing - proceedings of the 27th European Conference on Acoustic Emission Testing T2 - 27th European Conference on Acoustic Emission Testing (EWGAE 2006) CY - Cardiff, Wales, UK DA - 2006-09-20 KW - Composite calinders KW - Pressure equipment KW - Damage analysis PY - 2006 SN - 0-87849-420-0 N1 - Serientitel: Advances materials research – Series title: Advances materials research IS - 13-14 SP - 267 EP - 272 PB - Trans Tech Publ. CY - Zürich AN - OPUS4-13865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Implementation and current situation of introducing the Directives 97/23/EC in the German legislaton T2 - Seminar on the Technical Regulation on the Pressure Vessels" des Romanian Ministry of Industry and Ressources T2 - Seminar on the Technical Regulation on the Pressure Vessels" des Romanian Ministry of Industry and Ressources CY - Bucharest, Romania DA - 2001-09-30 PY - 2001 AN - OPUS4-6011 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Probability of Fatigue of Carbon-Fibre Windings - Tests and Calculation Models Researching Input data for Pressure Vessel Optimization T2 - 7th Cz/Ger Symposium 1999 (Proceedings) T2 - 7th Cz/Ger Symposium 1999 (Proceedings) CY - Liblice, Czech Republic DA - 1999-04-13 PY - 1999 AN - OPUS4-11588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Novak, Pavel A1 - Scholz, Irene A1 - Duffner, Eric T1 - Hydraulic cycling facility of BAM for extreme temperature tests T2 - StorHy-Jahrestreffen, BAM T2 - StorHy-Jahrestreffen, BAM CY - Berlin, Germany DA - 2007-02-26 PY - 2007 AN - OPUS4-14506 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Novak, Pavel A1 - Anders, Stefan A1 - Duffner, Eric T1 - Interlaboratory test of hydraualic cycling facilities T2 - StrHy-Jahrestreffen, BAM T2 - StrHy-Jahrestreffen, BAM CY - Berlin, Germany DA - 2007-02-26 PY - 2007 AN - OPUS4-14508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Three arguments for probabilistic dimensioning of hydrogen storage systems T2 - StorHy-Jahrestreffen, BAM T2 - StorHy-Jahrestreffen, BAM CY - Berlin, Germany DA - 2007-02-26 PY - 2007 AN - OPUS4-14510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra A1 - Moosavi, Robabeh A1 - John, Sebastian A1 - Schumacher, David A1 - Grunwald, Marcel A1 - Auster, Jürgen A1 - Szczepaniak, Marius A1 - Mair, Georg A1 - Waske, Anja T1 - Impact damage evaluation of hydrogen composite pressure vessels by analysing computed tomography images T2 - HyFiSyn Conference N2 - The objective of this work is to find a method that describes the degree of damage from an impact experiment. This experiment was performed on Composite Pressure Vessels (CPV) in order to find the correlation of impact damage to the residual burst pressure. Computed Tomography (CT) approach was used to capture the before and after impact condition of the CPVs. The Wasserstein function was used to calculate how much the after impact image has differed from the original one. In the end, a good correlation was obtained to the residual burst pressure. T2 - HyFiSyn Conference CY - Online meeting DA - 15.09.2021 KW - Hydrogen KW - Composite pressure vessel KW - Carbon fibre KW - Burst test KW - Image analysis KW - Computed tomography (CT) PY - 2021 SP - 31 EP - 32 AN - OPUS4-53494 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Bin A1 - Mair, Georg A1 - Islam, F. T1 - Evaluation methods for estimation of Weibull parameters used in Monte Carlo simulations for safety analysis of pressure vessels JF - Material Testing N2 - The test data for static burst strength and load cycle fatigue strength of pressure vessels can often be well described by Gaussian normal or Weibull distribution functions. There are various approaches which can be used to determine the parameters of the Weibull distribution function; however, the performance of these methods is uncertain. In this study, six methods are evaluated by using the criterion of OSL (observed significance level) from Anderson-Darling (AD) goodness of Fit (GoF), These are: a) the norm-log based method, b) least squares regression, c) weighted least squares regression, d) a linear approach based on good linear unbiased estimators, e) maximum likelihood estimation and f) method of moments estimation. In addition, various approaches of ranking function are considered. The results show that there are no outperforming methods which can be identified clearly, primarily due to the limitation of the small sample size of the test data used for Weibull analysis. This randomness resulting from the sampling is further investigated by using Monte Carlo simulations, concluding that the sample size of the experimental data is more crucial than the exact method used to derive Weibull parameters. Finally, a recommendation is made to consider the uncertainties of the limitations due to the small size for pressure vessel testing and also for general material testing. KW - Safety assessment KW - Weibull distribution parameters KW - Randomness KW - Sample size KW - Monte Carlo simulation PY - 2021 DO - https://doi.org/10.1515/mt-2020-0058 VL - 63 IS - 4 SP - 279 EP - 385 PB - De Gruyter AN - OPUS4-53105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Salvage pressure receptacles - Technical background N2 - The presentation reflects the questions that have been raised by member states and NGOs. As background information details on the question how to choose a suitable salvage pressure receptacle (SPR) are provided. This leads to the need for deleting the volume limitation for SPRs and to the discussions in 2014 and 2016 on this issue. As an adequate substitution for deleting the volume limit for SPRs it is proposed to limit the pressure receptacles to be stored in by a maximum pressure-volume-value of 1.5 Mio bar-litres. After some explanations to standardisation projects currently also tackling this pV-limit, some risk-based safety criteria for a limitation are mentioned with the focus of the consequence level and the general avoidance of catastrophic worst case scenarios. T2 - 57th session of TDG Sub-Committee CY - Online meeting DA - 30.11.2020 KW - Salvage pressure receptacle KW - Consequence KW - Catastrophe KW - Compressed gas PY - 2020 AN - OPUS4-53161 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Thomas, Sebastian T1 - Consequences of the reduced minimum burst pressure on the production surveillance N2 - First the acceptance rates resulting from the analysis of different minimum burst ratios and standards are displayed and explained. Especially the problems resulting from a further reduction if the minimum burst ratio are shown. For a better understanding of these results the process of analysing the acceptance rate is explained in detail. This contains the alleged contradiction between safety of samples due to its scatter while the rejected sample provides a higher mean strength. Then the importance of batch testing is explained and leads to the recommendation to have a strong interaction between provided mean strength and requested maximum of production scatter. T2 - 8 th WG on rev GTR 13 CY - Online meeting DA - 02.03.2020 KW - Minimum burst ratio KW - Production scatter KW - Mean burst pressure KW - Batch testing KW - Acceptance rate PY - 2020 AN - OPUS4-53147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Bock, Robert T1 - Burst strength and its scatter as key points of safety N2 - Based on the preliminary presentations in this task force it is repeated how a basic population scatters and its degradation influences properties statistically. There is a remainder on the issue of accepting borderline populations due to the minimum burst ratio requirement. Then it is explained in detail how the analysis of minimum requirements by a Monte-Carlo-simulation works. The result with respect to the further reduced minimum burst ratio of 2.0 is summarised and means a two-step approach of two scatter levels requiring two different minimum burst ratios. The methods for evaluating batch tests are analysed. A proposal for integration a statistical analysis is described in detail. Finally, the positive effect of proof testing is shown and its dependence from the real ageing is shown. This ends in the recommendation to have a stronger and quantitative look on real ageing and to follow the 2 proposed sets of criteria for a safe usage of hydrogen storage systems. T2 - 10th IWG on rev GTR 13 CY - Online meeting DA - 28.06.2021 KW - Basic population KW - Minimum burst ratio KW - Monte-Carlo-simulation KW - Borderline population KW - Batch test KW - Proof test KW - Ageing PY - 2021 UR - https://wiki.unece.org/download/attachments/128419731/GTR13-10-08%20BAM%20GTR%2013-2%20scatter%20criteria%20for%20min%20burst%202021-06-25.pdf?api=v2 AN - OPUS4-53149 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - JOUR A1 - Mair, Georg A1 - Hoffmann, Martin A1 - Scherer, Florian A1 - Schoppa, André A1 - Szczepaniak, Mariusz T1 - Slow burst testing of samples as a method for quantification of composite cylinder degradation JF - International journal of hydrogen energy N2 - The current practise to focus periodic retesting of composite cylinders primarily on the hydraulic pressure test has to be evaluated as critical. The test itself always causes a certain amount of micro damage to the cylinders but does not necessarily deliver sufficient and evaluable information. Thus BAM Federal Institute of Materials Research and Testing (Germany) moves the focal point to a new approach for validation of composite cylinders, based on destructive sample tests parallel to operation. Statistical assessment of results of these destructive tests is employed for the estimation of remaining safe service life, based on reliability demands. The estimated service life is also used for the determination of re-test periods of the examined population of composite cylinders. An essential aspect of this approach is the validation of current residual strength and its prediction at any point of service life. In cases of gas cylinders with very high cycle strength, residual strength cannot be quantified statistically by means of hydraulic load cycles. As a replacement, creep tests or burst tests may be employed. BAM suggests the 'slow burst test SBT' as a combination of these two test procedures. This is a compromise between the practicability of the (conventional) burst test and the practical relevance of sustained loads during service, to be tested in creep rupture tests. In this paper, a variety of 99 burst results of a cylinder design type used for breathing apparatus (CFRP with PE-liner) is evaluated. The influence of test procedure parameters and nature and intensity of artificial ageing on the test sample strength are analysed statistically. This leads to an evaluation of different procedures of artificial ageing and the recommendation to substitute conventional burst tests by slow burst tests for the assessment of composite pressure receptacles. KW - Slow burst test KW - Sample testing KW - Residual strength KW - Scatter KW - Mean value KW - Degradation KW - Pressure rate PY - 2014 DO - https://doi.org/10.1016/j.ijhydene.2014.04.016 SN - 0360-3199 VL - 39 IS - 35 SP - 20522 EP - 20530 PB - Elsevier CY - Oxford AN - OPUS4-30732 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mair, Georg A1 - Scherer, Florian A1 - Duffner, Eric T1 - Concept of interactive determination of safe service life for composite cylinders by destructive tests parallel to operation JF - International journal of pressure vessels and piping N2 - There is evidence that composite materials degrade under static loads. Consequently there is no way to design composite gas cylinders for unlimited service life. Yet this fact is not reflected by design standards for composite receptacles approved for the transport of dangerous goods or for stationary application. Unnecessary cost and weight result from this. Due to the degradation aspects of composites it is necessary to provide appropriate retesting procedures, which allow rejection of used vessels as is common practice for metallic receptacles. The current procedure of hydraulic tests appears to be an expensive procedure with serious doubts regarding its usefulness for composite cylinders. Consequently, an efficient method is needed, which allows limiting the life time to its safe maximum. It is thus recommended to combine retesting with the assessment of residual life time. Since relevant non-destructive methods are not yet sufficiently matured and standardized enough, a concept featuring destructive tests on composite cylinders parallel to operation should be considered. An alternative concept introduced here, proposes to substitute the hydraulic testing of 100% of a population by a probabilistic evaluation of destructive tests on samples parallel to operation. Intensified pre-fill inspections should be an additional component of such a concept. KW - Composite pressure cylinders KW - Onboard storage KW - Residual strength KW - Periodic inspection KW - Destructive testing KW - Cycle fatigue PY - 2014 DO - https://doi.org/10.1016/j.ijpvp.2014.05.003 SN - 0308-0161 VL - 120-121 SP - 36 EP - 46 PB - Applied Science Publ. Ltd. CY - Barking AN - OPUS4-31257 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Duffner, Eric A1 - Becker, Ben T1 - Safety in Hydrogen Supply - Sicherheit in der Wasserstoff-Versorgung N2 - This poster shows some aspects concerning how BAM contributes to safety in transport and acceptance of hydrogen as energy carrier. T2 - Evaluierung der BAM durch den Wissenschaftsrat CY - BAM, Berlin, Germany DA - 16.02.2016 KW - Safety assessment KW - Probabilistic approach KW - Efficiency in transportation PY - 2016 AN - OPUS4-39146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra A1 - Joannes, S. A1 - Bunsell, A. A1 - Mair, Georg A1 - Thionnet, A. T1 - Modelling an Improved NOL Ring Test Using a Reduced Volume Method for the Characterisation of composite Cylinders T2 - The 22nd International Conference on Composite Materials N2 - The reduced volume method has found a particular zone to be used for evaluating the strength of unidirectional composite materials. To validate the method, modelling an experimental test where it has the same basic assumption of the model had been carried out. The result was favourable as the model can predict the average value from the experiment and also the time dependent effect. T2 - The 22nd International Conference on Composite Materials CY - Melbourne, Australia DA - 11.08.2019 KW - NOL Ring test KW - Multiscale model KW - Reduced Volume Method KW - Composite pressure vessels KW - Fibre break PY - 2019 AN - OPUS4-48929 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Concept of a Probabilistic Approval Approach (PAA) N2 - This presentation explains how an PA-based approval concept could work and would substitute the most of deterministic requirements based on a risk based quantification of accepted failure rates. The concept of a probabilistic approval approach is based on 5 separate types of requirements: 1. Testing and evaluation of properties at Beginning of Life (BoL) 2. Artificial aging with residual strength assessment 3. Testing against dedicated accidental loads 4. Surveillance of production quality 5. Surveillance of degradation/ check of estimated end of life (EoL) Each of these aspects is visualised by photos and diagrams. T2 - FiBreMoD Training Unit #5 CY - BAM-FB, Berlin, Germany DA - 04.10.2017 KW - Beginning of life KW - End of safe service life KW - Artificial ageing KW - Design type testing KW - Accidental loads KW - Survaillance of degradation PY - 2017 AN - OPUS4-43111 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg T1 - Tasks and needs of a competent authority for gas storage N2 - This presentation provides an impression of the boundary condition of the work on composite cylinders on a competent authority. It shows the various kinds of usage, the different tasks and duties around this kind of storage units and the wide spread of technical competence necessary for the substantial research when addressing the legislation. Based on this it shows how we react on changes in the regulations by research and how this influences the regulations, again. As an example, our probabilistic approach is mentioned and drafted for getting mentioned several times during the ongoing set of presentations. T2 - FiBreMoD Training Unit #5 CY - BAM-FB, Berlin, Germany DA - 05.10.2017 KW - Advisement KW - Frequency KW - Consequence KW - Safety assessment KW - NDT PY - 2017 AN - OPUS4-43085 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Saul, Herbert A1 - Duffner, Eric T1 - Composite Pressure Vessels for Hydrogen - Research for Safety N2 - Referring to the inter-departmental project group "Pressure Equipment" and the section "Pressure Equipment-pressure receptacles; Fuel Gas Storage Systems" developed from, it is shown here how research on safety aspects, technical regulations and the activities of the Federal Institute BAM in its role as competent authority interact to the advantage of safety of composite pressure vessels. T2 - FiBreMoD Steering Committee Meeting and Training Unit #5 CY - BAM Berlin, Germany DA - 04.10.2017 KW - Pressure Equipment KW - ECE R110 KW - TPED KW - StorHy KW - HyComp KW - Service life tests KW - UN composite cylinders KW - PN020 KW - GTR KW - ECE R134 KW - Competent authority PY - 2017 AN - OPUS4-42461 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 -