TY - CONF A1 - Zaghdoudi, Maha A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Simulation of compression set of epdm o-rings during aging N2 - It is common practice in the application of finite element analysis to model compression set (CS) of elastomers during aging with two different material models according to the two-network theory of Tobolsky. The theory relies on the existence of two networks. The first one represents the original network after vulcanization and is sensitive to chain scission. The second network accounts for the formation of additional crosslinking during aging. Besides the use of user subroutines to describe the two-network model, an element overlay technique is also needed as the full set of both material behaviors did not exist for assignment to a single element. This element overlay technique is valuable for research and developmental purposes but makes extension to industrial usage quite challenging. Our goal is to simulate the CS of elastomers after long-term aging in a commercial finite element software with no need for extra subroutine codes or mesh superposition. Ethylene propylene diene (EPDM) O-rings were aged in a compressed state at 75 °C, 100 °C, 125 °C and 150 °C for up to 183 days. Investigations of the experimental test results were used to identify material models and their parameters to develop a finite element model to simulate CS. The model was implemented in the finite element software ABAQUS/Standard® with a sequential temperature-displacement coupling. Regarding the influence of temperature, the Arrhenius equation is adopted for the time-temperature relationship. The activation energy value that is required for the simulation is firstly determined from shifting the experimental CS results with the time-temperature superposition technique and plotting the shift factors in an Arrhenius diagram. The experiments were compared with the simulation results. Afterwards different activation energies were used in the simulation and discussed. A suitable choice of the activation energy value with regard to the reference temperature and the test temperature is presented. With the chosen activation energies, the match between numerical CS values after long-term aging and the experimental results was improved. T2 - ASME 2022 Pressure Vessels & Piping Conference CY - Las Vegas, USA DA - 17.07.2022 KW - Simulation KW - Compression set KW - EPDM KW - Aging PY - 2022 SP - 1 EP - 9 AN - OPUS4-57370 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Albouy, P.-A. A1 - Häcker, Ralf A1 - Stock, Daniel T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at bam N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses. Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios. At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy. This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed. T2 - PATRAM22 CY - Juan-Les-Pins, Antibes, France DA - 11.06.2023 KW - (U)HMWPE KW - Ageing KW - Irradiation KW - WAXD KW - SHPB PY - 2023 SP - 1 EP - 10 AN - OPUS4-57707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Overview of ongoing long-term ageing investigations on elastomer seals N2 - At the Bundesanstalt für Materialforschung und -prüfung (BAM) in Division 3.4 Safety of Storage Containers, one of our tasks is to evaluate the safety of containers designed for disposal of low and intermediate radioactive waste. As such containers might be transported before and stored until disposal, safe enclosure of the radioactive inventory is important for this time span. Elastomer O-rings are widely used as barrier seals in these containers. Thus, as for many other applications, an understanding of the practical effects of ageing degradation on elastomer seals during long-term exposure is mandatory for predicting the lifetime of such components. According to a long-term test programme on three kinds of rubbers (EPDM and FKM (relevant for application), HNBR (for comparison)), over several years we have studied the degradation and the change of mechanical properties (e.g. hardness, strain at break) at four different ageing temperatures (75 °C, 100 °C, 125 °C and 150 °C) as well as the change of sealing properties. Continuous and intermittent compression stress relaxation (CSR) measurements were performed in order to investigate the respective contribution of crosslinking and chain scission to the observed degradation effects. Thus, the degradation kinetics and mechanisms could be resolved more clearly. For assessing the seal performance, compression set (CS) and leakage rate measurements were conducted. The experimental results showed that the O-rings remained leak-tight under purely static conditions even when CSR, CS and mechanical properties already indicated far advanced degradation. For this reason, a modified leakage test involving a small and rapid partial decompression of the seal was developed that enabled determining an end-of-lifetime criterion for O-rings with a safety margin for thermal shrinkage and vibrations. KW - Seal KW - O-Ring KW - Ageing KW - Component tests PY - 2020 SN - 1863-7116 VL - 15 IS - 3 SP - 146 EP - 151 PB - Gupta CY - Ratingen AN - OPUS4-51161 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Übersicht über laufende Untersuchungen zur Langzeitalterung von Elastomerdichtungen N2 - Eine Aufgabe des Fachbereichs 3.4 Sicherheit von Lagerbehältern der Bundesanstalt für Materialforschung und -prüfung (BAM) ist es, die Sicherheit von Behältern zur Lagerung von radioaktivem Abfall mit vernachlässigbarer Wärmeentwicklung zu bewerten. Da solche Behälter vor der Entsorgung transportiert und gelagert werden, ist während dieser Zeit ein sicherer Einschluss des radioaktiven Inhalts von größter Bedeutung. Zur Abdichtung dieser Behälter sind Elastomer-O-Ringe weit verbreitet. Um für solche, wie auch für viele andere Anwendungen, eine Voraussage über die Lebensdauer dieser Komponenten treffen zu können, ist es unerlässlich zu verstehen, welchen Einfluss der durch Alterung hervorgerufene Abbau auf Dauer auf die Elastomerdichtungen hat. In einem Langzeittest wurden drei Kautschukarten (EPDM und FKM, die für die Anwendung relevant sind, und HNBR als Vergleich) über mehrere Jahre untersucht. Dabei wurden die Veränderungen der mechanischen Eigenschaften (z. B. Härte und Bruchdehnung) bei vier verschiedenen Alterungstemperaturen (75 °C, 100 °C, 125 °C und 150 °C) sowie das Dichtungsverhalten betrachtet. Um den Einfluss von Vernetzung und Kettenspaltung auf die beobachteten Alterungseffekte zu bestimmen, wurden Messungen zur kontinuierlichen und intermittierenden Druckspannungsrelaxation durchgeführt. Dadurch konnten Erkenntnisse über Kinetik und Mechanismus der Abbaureaktionen gewonnen werden. Zur Einschätzung des Dichtungsverhaltens wurden Durckverformungsrest und Leckagerate gemessen. Die Ergebnisse zeigen, dass die O-Ringe unter statischen Bedingungen auch dann dicht halten, wenn die Werte für Druckverformungsrest, Druckspannungsrelaxation und mechanische Eigenschaften schon auf einen fortgeschrittenen Alterungsabbau hindeuten. Aus diesem Grund wurde ein modifizierter Dichtigkeitsversuch mit einer geringen und schnellen teilweisen Entlastung der Dichtung entwickelt, mit dessen Hilfe sich ein Lebensdauerkriterium bestimmen lässt, das eine Sicherheitsspanne für thermische Schrumpfung und Vibrationen beinhaltet. KW - Alterung KW - O-ring KW - Elastomer Dichtung PY - 2020 SN - 0176-1625 VL - 73 IS - 07-08 SP - 326 EP - 332 PB - Gupta CY - Ratingen AN - OPUS4-51207 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Zaghdoudi, M. A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar ED - Altenbach, H. ED - Hitzler, L. ED - Johlitz, M. ED - Merkel, M. ED - Öchsner, A. T1 - Analysis of Heterogeneous Ageing of HNBR O-Rings N2 - Abstract Hydrogenated nitrile butadiene rubber (HNBR) elastomer was thermo-oxidatively aged at different temperatures up to 150 °C. Fourier transform infrared spectroscopy (FTIR), compression stress relaxation (CSR) and international rubber hardness degree (IRHD) microhardness were used to characterise the chemo-mechanical changes of HNBR O-rings during thermo-oxidative ageing. FTIR shows the development of carbonyl, methyl and ester groups but the nitrile content was not affected by ageing. The effect of sample geometry during CSR was investigated. CSR data were converted through integrated kinetic laws. The conversion has proven its sensibility to detect heterogeneous ageing. This was confirmed by the IRHD measure-ments across the section of O-rings. The influence of compression during ageing was assessed through IRHD measurements across the section of compressed and uncom-pressed aged O-rings. The DLO effect was more pronounced in compressed O-rings. By applying the model of Wise et al., theoretical IRHD and oxidation profiles were determined on the basis of IRHD experimental data of compressed O-rings. Good agreements between the experimental and the theoretical IRHD profiles in the core region were obtained. However, near the edge, the theoretical IRHD values were overestimated. KW - Ageing KW - Rubber seals KW - Stress relaxation KW - Modelling PY - 2024 SN - 978-3-031-49042-2 U6 - https://doi.org/10.1007/978-3-031-49043-9 SN - 1869-8433 SP - 331 EP - 348 PB - Springer Nature CY - Cham, Switzerland AN - OPUS4-59769 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Wolff, Dietmar A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Goering, Harald ED - Yamamoto, T. T1 - (U)HMWPE as neutron radiation shielding materials: impact of gamma radiation on structure and properties N2 - Due to their extreme high hydrogen contents, high molecular weight (HMW-) and ultra-high molecular weight (UHMW-) polyethylene (PE) are a comprehensible choice as neutron radiation shielding material in casks for storage and transport of radioactive materials. But as a direct consequence of inserting radioactive material in such casks, gamma radiation occurs. Hence, the impact of gamma radiation on the molecular structure of polyethylene has to be taken into consideration. Consequently, PE has to withstand any type of gamma radiation induced degradation affecting safety relevant aspects in order to be applicable for long term neutron radiation shielding purposes during the whole storage period (in Germany, for instance, up to 40 years). The scope of our investigation comprises an estimation of the impact of gamma radiation and temperature on the molecular and supra molecular structure of the two types of PE used as neutron radiation shielding cask components. A further point which is worth exploring is to what extent these changes are detectable by conventional analysis methods. Therefore, thermoanalytical measurements were performed such as differential scanning calorimetry (DSC), thermo mechanical analysis (TMA), dynamic mechanical analysis (DMA), and thermo gravimetric analysis (TGA). Additionally optical and weighing methods were applied. With those methods it is possible to detect structural changes in polyethylene induced by exposure to gamma radiation. The observed amounts of changes of the irradiated material are not safety relevant for the application of polyethylene as neutron radiation shielding material; moreover, some properties actually improve via irradiation. KW - HMW-PE KW - UHMW-PE KW - Gamma irradiation KW - Neutron radiation shielding material PY - 2013 SN - 978-0-8031-7533-4 U6 - https://doi.org/10.1520/STP103980 N1 - Serientitel: STP – Series title: STP VL - 25 IS - STP 1547 SP - 211 EP - 227 AN - OPUS4-27931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolff, Dietmar A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin T1 - Performance of neutron radiation shielding material (U)HMW-PE influenced by gamma radiation T2 - PSAM 11 ESREL 2012 - 11th International probabilistic safety assessment and management conference & The annual european safety and reliability conference CY - Helsinki, Finland DA - 2012-06-25 KW - (U)HMW-PE KW - Gamma irradiation KW - Shielding material KW - Cask for storage and transport of radioactive materials PY - 2012 SP - 1 EP - 8(?) AN - OPUS4-26176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Jaunich, Matthias A1 - Kömmling, Anja A1 - Völzke, Holger A1 - Schulze, Dietmar T1 - Numerical simulation of the behaviour of elastomer seals under consideration of time dependent effects N2 - Due to delays in the site-selection procedure to establish a deep geological repository for spent nuclear fuel and high level waste and in construction of the already licensed Konrad-repository for low and intermediate level waste without heat generation, extended periods of interim storage become more relevant in Germany. BAM is involved in most of the cask licensing procedures and especially responsible for the evaluation of cask-related long-term safety issues. The long-term performance of elastomer seals for lid Systems of transport and storage casks whether used as auxiliary seals in spent fuel caslcs or as primary seals for low and intermediate level waste packages is an important issue in this context (Jaunich, 2013; Jaunich, 2014; Kömmling, 2015). The polymeric structure of these seals causes a complex mechanical behaviour with time-dependent elasticity reduction and loss of elastic recovery. The paper presents first results of a comprehensive test Programme consisting of several static and dynamic mechanical short- and long-term tests which have been carried out at BAM on specimens made of representative types of elastomers, fluorocarbon rubber (FKM) and ethylene propylene diene rubber (EPDM). The investigation of the test results used to identify material models and their Parameters as well as the development of two finite element models for the numerical Simulation of tension and compression tests using the finite element code ABAQUS® are described. The calculation results are presented in comparison to the test results. The influence of important material and test parameters was investigated and discussed in sensitivity analyses. T2 - RAMTRANSPORT 2015 - International conference on the radioactive materials transport and storage CY - Oxford, UK DA - 19.05.2015 KW - Numerical analysis KW - Extended interim storage KW - Elastomer seals PY - 2015 SP - Session 4, Paper 28, 1 EP - 9 AN - OPUS4-33832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Zaghdoudi, Maha A1 - Brandt, Guido A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Coefficients of Friction in Dependence on Aging State of Elastomers – Experimental Identification and Numerical Simulation of the Experiment N2 - Elastomer seals are mounted as barrier seals in lid systems of containers designed for transport and disposal of negligible heat generating radioactive waste and as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). When the behavior of mounted seals under normal and hypothetical accident conditions of disposal and transport is to be simulated, a comprehensive knowledge of their complex mechanical properties at every state of aging is necessary. In previous works, BAM’s efforts in experimental investigations on specimen artificially aged at different temperatures and times and the implementation of the found results in finite element material models were presented. Additionally, our approaches to reproduce the aging process itself and to extrapolate the results of artificially accelerated aging to longer times were presented. Numerical simulations have shown that the behavior of the seal during mounting and one-sided pressurizing and the resulting performance values such as leakage rate strongly depend on the coefficient of friction (COF) between flange and seal. The friction coefficient, in turn, depends on the aging state of the elastomer material as several publications suggest (see below). Dynamic COF between an exemplary ethylene propylene diene rubber (EPDM) material and a stainless steel ball were determined by using a self-designed linear oscillation tribometer. Unaged and artificially aged EPDM specimen stored for 30 days and 100 days at a temperature of 150 °C were tested. A stainless steel ball (d=10 mm) is brought in contact with the specimen’s surface und loaded by normal forces of 2.5 N, 5 N, 10 N and 20 N. During a reciprocating movement of the EPDM sheet, the horizontal force/friction force is continuously measured, and the COF can be derived. It is well known that friction is a complex phenomenon especially in soft materials. It cannot be excluded that the measured friction force is influenced by additional force components, resulting from the ball’s grooving through the elastomer’s surface. This force depends on the penetration depth of the ball and on the resistance of the elastomer in its different states of aging. The latter results from microstructural changes i.e., chain scission and additional crosslinking that occur during aging which in turn influence the softening or hardening of the material. A finite element (FE) ABAQUS® model was developed to reproduce the measurement process. It should help to better understand the physical mechanisms and to quantify the percentage of measured forces resulting from real friction on the one hand and forces resulting from unintended side effects that could falsify the result on the other hand. The behavior of the elastomer in its different states of aging is reproduced by a FE material model already presented in previous works of BAM. T2 - ASME 2022 Pressure Vessels & Piping Conference (PVP2022) CY - Las Vegas, NV, USA DA - 17.02.2022 KW - Numerical Simulation KW - Radioactive Waste KW - Elastomers KW - Aging KW - Seal Behavior KW - Leakage Rate KW - Coefficient of Friction KW - Experiment PY - 2022 SP - 1 EP - 8 PB - American Society of Mechanical Engineers (ASME) CY - New York, NY, USA AN - OPUS4-57093 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Böhning, Martin A1 - Goering, Harald T1 - Radiation induced structural changes of (U)HMW polyethylene with regard to its application for radiation shielding N2 - The special properties of high molecular weight polyethylene (HMW-PE) and ultra high molecular weight polyethylene (UHMW-PE) result basically from their extreme chain lengths and their high degree of crystallinity. As high-performance polymers, they are used for a variety of applications. UHMW-PE in particular is often utilized for endoprothesis (due to its excellent slip and wear properties) and due to its high hydrogen content as a neutron moderator in casks for storage and transport of radioactive materials. To prepare the material for instance for its use as a total joint replacement, it is exposed to radiation for several reasons, such as sterilization and crosslinking, leading to partial improvement of the mechanical properties (e.g. fracture toughness, crack propagation resistance, wear resistance) and better chemical stability. To be applicable for long term radiation shielding purposes for instance over a period of 40 years, PE has to withstand any type of degradation affecting safety relevant aspects. The scope of our investigation comprises an estimation of the radiation impact on the molecular and supra molecular structure of two types of PE and to what extent these changes are detectable by thermo-analytical (TA) methods, such as Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) and Thermo Gravimetric Analysis (TGA). Additionally FT-IR spectroscopy as well as density and gas sorption measurements were carried out. Due to the poor solubility of HMW-PE and UHMW-PE, some classical analytical techniques are not applicable. But TA-methods represent a feasible approach to detect structural and morphological features of these materials as well as changes caused by external influences, such as thermal treatment and/or irradiation. With the combination of the applied TA-techniques it is possible to distinguish between crosslinking and degradation. T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 PY - 2010 SP - 1 EP - 8 (T25/Paper 173) AN - OPUS4-24621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - UHMW-PE - a shielding material with special properties influenced by radiation N2 - Ultra high molecular weight polyethylene (UHMW-PE) - due to its high hydrogen content - is used as neutron shielding material in casks for storage and transport of radioactive materials. Besides this, UHMW-PE - as a high-performance polymer - has been used for several years in medical technology due to its excellent slip and wear properties. Due to the special properties of UHMW-PE which result basically from its extreme chain lengths and its high degree of crystallinity, it is predestinated for the aforementioned applications. In both cases, irradiation and its impact on the molecular structure of polyethylene play an important role. In the first case, irradiation exists as a by-product of inserting the radioactive material in the cask. Hence PE has to withstand any type of degradation affecting safety relevant aspects to be applicable for long term radiation shielding purposes for instance over a period of 40 years. In the second case irradiation is applied deliberately for purposes such as sterilization and crosslinking, leading to partial improvement of the mechanical properties (e.g. fracture toughness, crack propagation resistance, wear resistance) and better Chemical stability. Specifically concerning their use in the field of medical technology, different types of UHMW-PE have been objects of numerous publications. It is generally accepted that two parallel and competitive processes, based on chain scission and reactions of Ccentered radicals and molecular fragments, occur in PE as a consequence of radiation: radical recombination accounts for crosslinking, together with some disproportionation, formation of low molecular weight fragments, and recrystallization. Furthermore, formation of oxygenated structures in the presence of traces of oxygen is an antagonist of the C-centered radicals. Radiation induced scission preferentially takes place in the amorphous phase and noncrystalline surface of the crystals. It is followed by folding of molecular fragments, crystallinity growth and increased perfection in the crystal lamellae [4, 5]. Chain scission results in shorter polymer molecules, fewer entanglements, and consequently, increased molecular mobility. The scope of our investigation comprises an estimation of the radiation and thermal impact on the molecular and supra molecular structure of the two types of PE used for neutron shielding cask components. A further point which is worth to explore is to what extent these changes are detectable by thermo-analytical (TA) methods, such as Differential Scanning Calorimetry (DSC), Thermo Mechanical Analysis (TMA), Dynamic Mechanical Analysis (DMA) and Thermogravimetry (TG). Additionally FT-IR and solubility measurements have been performed. In our studies we focused on the UHMW-PE material GUR 4120 which was y irradiated at RT and compared to the untreated material. T2 - Jahrestagung Kerntechnik 2011 CY - Berlin, Germany DA - 17.05.2011 PY - 2011 SP - 1 EP - 5 AN - OPUS4-24620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - von der Ehe, Kerstin A1 - Jaunich, Matthias A1 - Böhning, Martin A1 - Goering, Harald A1 - Wolff, Dietmar T1 - Detection of structural changes of (U)HMW-PE induced by gamma irradiation T2 - 14th International conference "Polymeric materials" CY - Halle (Saale), Germany DA - 2010-09-15 PY - 2010 SN - 978-3-86829-282-4 SP - 1 EP - 6 PB - Druck-Zuck GmbH CY - Halle / Saale AN - OPUS4-21997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Trappe, Volker A1 - Günzel, Stephan A1 - Jaunich, Matthias ED - Yao, W. ED - Renard, J. ED - Himmel, N.A. T1 - Correlation between crack propagation rate and cure process of epoxy resins KW - Fracture toughness KW - Crack resistance KW - Fracture mechanics KW - Plastics KW - Crack propagation PY - 2012 SN - 978-1-60595-091-4 SP - 277 EP - 290 PB - DEStech Publications, Inc. CY - Lancaster, PA, USA AN - OPUS4-27947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Subramani Bhagavatheswaran, E. A1 - Wießner, S. A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Einfluss der Alterung auf dichtungsrelevante Eigenschaften von FKM-, VMQ- und EPDM-Elastomeren N2 - Da Elastomere in vielfältigen Dichtungsanwendungen eingesetzt werden und dabei teilweise großen Einfluss auf die Funktionsfähigkeit und Sicherheit haben, ist der Einfluss der Alterung auf dichtungsrelevante Eigenschaften relevant. Eine strukturierte Untersuchung des Einflusses von verschiedenen Mischungsrezepturen auf die Bauteileigenschaften, das Alterungsverhalten und die Funktion wird vorgestellt. T2 - Technomer 2017 CY - Chemnitz, Germany DA - 09.11.2017 KW - Dichtung KW - Alterung KW - Struktur-Eigenschaftsbeziehung KW - Elastomer PY - 2017 SN - 978-3-939382-13-3 VL - 2017 SP - 41 EP - 41 AN - OPUS4-42844 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Subramani Bhagavatheswaran, E. A1 - Wießner, S. A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Aging study and electrical resistance based stress-monitoring of rubber seals N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste. In addition, they are also used in waste fuel storage and transportation casks as auxiliary seals. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with respect to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. A fundamental understanding of the structure property relationship and their changes during aging can help to evaluate the long-term sealing performance. In the present study, specific materials are investigated to study the structure-property and seal performance-correlation. Fluoro-elastomer (FKM), silicone rubber (VMQ) and ethylene propylene diene rubber (EPDM) were chosen as base rubbers. Comparable mechanical properties for these seals, especially in terms of a comparable compression behavior were achieved by careful control of base rubber formulation, i.e., by opting for the right filler and its concentration, amount of crosslinking chemicals, and with the assistance of process oils. Moreover, with the same rubber, similar mechanical properties were achieved by varying the filler concentration and crosslinking degree, which shall enable to correlate the particular influence on the structure property dependency of the seals in detail. The materials are investigated under pristine and aged conditions to evaluate the influence of aging, e.g. on the stress relaxation or recovery behavior. These values appear to be suitable parameters to judge the expected sealing performance. Due to the electrically conducting nature of some fillers used to reinforce rubbers (such as carbon blacks, carbon nanotubes (CNTs), Graphene, etc.) it is possible to obtain current information about mechanical and visco-elastic properties by monitoring the electrical conductivity or resistivity. A simple relation that relates electrical resistance with mechanical stress was derived and the stress values were theoretically predicted from the electrical resistance values, which showed good correlation with experimental results. T2 - 192nd Technical meeting of the ACS Rubber Division CY - Cleveland, OH, USA DA - 09.10.2017 KW - Seal KW - Rubber KW - Degradation KW - Structure-property relationship KW - Ageing PY - 2017 VL - 2017 SP - 1 EP - 25 AN - OPUS4-42849 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stark, Wolfgang A1 - Jaunich, Matthias T1 - Thermoanalytische Charakterisierung von Ethylen-Vinylacetat-Copolymer (EVA) für Photovoltaikmodule N2 - Das Ziel der Untersuchungen war mit Hilfe von DSC und DMA EVA-Folien im Anlieferungszustand hinsichtlich der Lage der Glasübergangstemperatur, des Schmelzverhaltens und der Temperaturabhängigkeit der Vernetzungsreaktion zu charakterisieren. Auf dieser Basis sollte die Lieferstabilität im Sinne einer Wareneingangskontrolle auf eine messtechnische Basis gestellt werden. In einem 2. Schritt sollte die vernetzte Folie dahingehend charakterisiert werden, ob infolge der Vernetzung eine Änderung der KW - Photovoltaik KW - Klebfolie KW - EVA KW - DSC KW - DMA PY - 2011 VL - 8 SP - 3 EP - 5 AN - OPUS4-24168 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shirai, K. A1 - Namba, K. A1 - Wataru, M. A1 - Völzke, Holger A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Schulz, Sebastian T1 - Numerical evaluation of the long-term sealing performance of the silver gasket for dual purpose metal cask under high temperature N2 - It is important to evaluate the effect of thermal ageing on the sealing performance of metal gaskets under high temperature for long-term usage. Therefore, in order to gain representative data for this kind of metal-sealed lid System, BAM is currently performing laboratory tests of different gasket types with aluminum and silver jackets at three different temperatures under static conditions up to four years so far, using test flanges for gaskets with full scale cross section diameter but much smaller outer diameter. On the other hand, in order to investigate the applicability of the numerical methodology to evaluate the long-term behavior of the metal gaskets, such as a correlation between seal pressure force and holding time, CRIEPI is developing a modeling method including material tests (tensile and creep tests) at high temperature. In this paper, the applicability of the finite element method (ABAQUS) to predict the recovery displacement and residual seal pressure force of the gasket complex was verified by comparing the calculated values with BAM’s laboratory test results under the joint research agreement between BAM and CRIEPI. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 KW - Metal seals KW - Extended storage KW - Long-term storage KW - Dual purpose cask PY - 2013 SP - 1 EP - 8 PB - Omnipress AN - OPUS4-31947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Probst, Ulrich A1 - Schulz, Sebastian A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Völzke, Holger ED - Berger, K.-F. ED - Kiefer, S. T1 - Langzeituntersuchungen an Metalldichtungen mit innen liegendem Federkern und doppelter Ummantelung N2 - In Deutschland werden in Transport- und Lagerbehältern (TLB) wärmeentwickelnde radioaktive Abfälle gegenwärtig über einen Zeitraum von bis zu 40 Jahren zwischengelagert. Aufgrund der Situation der noch nicht abgeschlossenen Endlagersuche werden hier möglicherweise Verlängerungen in Betracht zu ziehen sein. Im Deckeldichtsystem der TLB werden in der Regel Metalldichtungen vom Typ Helicoflex® eines französischen Herstellers verwendet, die aus einem innen liegenden Spiralfederkern und zwei Ummantelungen bestehen. Die Ermittlung der Fliess- und Relaxationseigenschaften der Dichtungskomponenten über den vorgesehenen langen Betriebseitraum sind vor dem Hintergrund des Erhalte eines geforderten hohen Dichtniveaus ein wichtiger Untersuchungsgegenstand. KW - Metalldichtung KW - Langzeiteignung KW - Dichtsysteme KW - Transport- und Lagerbehälter für radioaktive Stoffe PY - 2013 SN - 978-3-9811509-7-1 SP - 1 EP - 11 CY - Mannheim AN - OPUS4-28912 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liu, Yung A1 - Völzke, Holger A1 - Zencker, Uwe A1 - Jaunich, Matthias T1 - Cooperation in Advanced Technologies Associated with the Back End of Nuclear Fuel Cycle N2 - A Memorandum of Understanding (MOU) between Argonne National Laboratory (Argonne) and the German Bundesanstalt für Materialforschung und -prüfung (BAM) was signed in October 2014. Its objectives are to promote cooperation among scientists and specialists at Argonne and BAM and establish a framework for collaboration in advanced technologies associated with the back end of the nuclear fuel cycle. Collaborative activities involving Argonne and BAM may be implemented through the promotion of joint research activities and scientific workshops and conferences; exchange of technical information; and visits by scientists, specialists, and graduate, postgraduate, and Ph.D. students. The MOU was renewed in January 2020 for another five years. Highlights of the progress and achievements are provided in identified topical areas for collaboration on ageing management guidance, storage, transportation and disposal R&D, joint conference activities, and conclude with the benefits of the MOU in fostering Argonne and BAM collaboration. T2 - 26th International Conference on Structural Mechanics in Reactor Technology - SMiRT 26 CY - Potsdam, Germany DA - 10.07.2022 KW - Nuclear fuel cycle KW - Back end KW - Spent fuel performance KW - Storage KW - Transportation PY - 2022 SP - 1 EP - 10 AN - OPUS4-55861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Kömmling, Anja A1 - Wolff, Dietmar A1 - Jaunich, Matthias ED - van Breugel, K. ED - Koleva, D. ED - Beek, T. T1 - Investigation of long-term behaviour of elastomeric seals for transport and storage packages N2 - Elastomers are widely used as the main sealing materials in Containers for low- and intermediate-level radioactive waste and as an additional component fo metal seals in spent-fuel and high-level waste containers. According to appropriate guidelines and regulations, safe enclosure of the radioactive container contents has to be guaranteed for lengthy storage periods of at least 40 years. Therefore, the understanding of seal ageing behaviour is of high importance and has to be considered with regard to possible dynamic events taking place during transport after storage. An accelerated ageing approach for compressed seals is presented, as well as some first results. KW - O Ring KW - Ageing KW - Rubber seal PY - 2018 SN - 978-3-319-70192-9 U6 - https://doi.org/10.1007/978-3-319-70194-3_2 SP - 17 EP - 25 PB - Springer AN - OPUS4-43248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Simbruner, Kai A1 - Grelle, Tobias A1 - Jaunich, Matthias A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Orellana Pérez, Teresa A1 - Völzke, Holger T1 - Research at BAM for evaluating long term safety of container systems and components N2 - Safety of long term containment and storage of radioactive waste is an essential issue, which is increasingly gaining international attention. Extending interim storage beyond initial license periods is one of the major challenges worldwide. BAM has been involved in all kinds of radioactive waste container safety evaluation for storage and transportation including their long term performance from the very beginning. Today, all work related to the safe management of radioactive waste is linked by the activity field “Nuclear Waste Management” within the Focus Area “Energy” at BAM and in conjunction with a research strategy and agenda. Most recently, the working group “Long Term Safety of Container Systems and Components” was established to launch and perform research projects related to safety issues concerning the extended interim storage of radioactive waste. For example, within our project LaMEP, we investigate ageing effects of metal and elastomer seals as well as polymeric neutron shielding materials, which are container components that fulfil major safety functions. The results of the experiments help to understand the long term behaviour of these components. Likewise, our project BRUZL started at BAM in 2018 with the aim of developing a fracture mechanics approach to understand and describe a potential brittle failure mechanism of fuel cladding during long-term interim storage. BAM also contributes to the GRS project “Development of methods and models and international exchange for safety evaluation in the frame of interim storage of radioactive waste”. Additionally, BAM is involved in several international research programmes dealing with extended interim storage, such as the European Joint Programme on Radioactive Waste Management (EURAD), the Extended Storage Collaboration Program (ESCP) and IAEA Coordinated Research Projects. The present contribution provides a comprehensive overview of BAM research activities contributing to national and international gap analyses and to filling knowledge gaps regarding the safe long term management of radioactive waste. T2 - Annual Meeting on Nuclear Technology 2019 CY - Berlin, Germany DA - 07.05.2019 KW - Radioactive Waste KW - Long-term safety PY - 2019 SN - 978-3-926956-95-8 SP - 1 EP - 5 AN - OPUS4-51486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Influence of Ageing on Sealability of HNBR, EPDM and FKM O-rings N2 - At BAM, which is the federal institute for materials research and testing in Germany, it is one of our tasks to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes assessment of elastomeric seals applied in the containers. Besides examining the low-temperature behaviour and irradiation effects of elastomeric seals, it is our goal to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Therefore, we started an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) which are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) up to 1 year. In order to assess sealability, O-rings are aged in compression by 25 % (corresponding to the compression during service) between plates as well as in flanges that allow leakage rate measurements. For comparison, uncompressed O-rings are aged as well. Further methods characterising seal performance are compression stress relaxation (CSR) reflecting the loss of sealing force of a compressed seal over time, and compression set (CS) which represents the recovery behaviour of a seal after release from compression. Additionally, hardness is measured for information about the change of mechanical properties. The experimental results indicate that while hardness, CSR and CS show considerable degradation effects, the leakage rate stays constant or even decreases until shrinkage and the loss of resilience of the aged seal leads to the formation of a leakage path. This indicates that static leakage rate, which is the only available direct seal performance criterion, has only limited sensitivity for the degradation of the seal material. T2 - International Sealing Conference CY - Stuttgart, Germany DA - 12.10.2016 KW - Rubber KW - Seal KW - Degradation PY - 2016 SN - 978-3-8163-0674-9 VL - 2016 SP - 551 EP - 563 PB - VDMA AN - OPUS4-38014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Aging of elastomeric seals for storage casks N2 - Elastomeric seals are used in many containers, including casks for radioactive waste. However, like all polymers, elastomers are prone to aging, which leads to a loss of sealing force and the ability for recovery which can ultimately result in leakage. Therefore it is important to be able to define an end-of-lifetime criterion and to judge the lifetime of elastomeric seals. For this reason, we started an aging program on three kinds of rubbers (HNBR, EPDM, FKM), monitoring the change of properties at four different aging temperatures over extended periods up to five years. The measured data is used for lifetime prediction by applying a suitable model. T2 - WM2015 Conference CY - Phoenix, Arizona, USA DA - 15.03.2015 KW - Aging KW - Elastomer KW - Seal KW - Leakage KW - Compression PY - 2015 SN - 978-0-9828171-4-8 SP - 15080, 1 EP - 12 AN - OPUS4-33253 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Ageing and lifetime prediction of O-ring seals made of HNBR, EPDM and FKM N2 - BAM is the federal institute for materials research and testing in Germany. One of our tasks is to evaluate the safety of casks designed for transport and/or storage of radioactive waste. As elastomeric seals are used in the containers as safety-relevant parts, it is our goal to be able to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. For this reason, an accelerated ageing programme with selected rubbers often used for seals (HNBR, EPDM and FKM) was started. Ageing was performed at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) for up to 2 years. For assessing properties related to the sealability, O-rings were aged in compression by 25 % (corresponding to the compression during service) between plates. For comparison, uncompressed O-rings were aged as well. The aged materials were characterized with conventional polymer analysis methods such as hardness and tensile tests, but also with more seal-specific methods such as compression stress relaxation (CSR, reflecting the loss of sealing force of a compressed seal over time), and compression set (CS, representing the recovery behaviour of a seal after release from compression). CS is chosen as the property for lifetime prediction as it is both sensitive to degradation and related to the seal performance. CS data is extrapolated to 60 °C, which yields lifetimes of approximately 5 years for HNBR and 64 years for EPDM for a criterion of 85 % CS respectively, and approx. 40 years for FKM for a criterion of 65 % CS (the highest value measured so far). T2 - 12. Kautschuk Herbst Kolloquium CY - Hanover, Germany DA - 22.11.2016 KW - Rubber KW - Compression set KW - Extrapolation KW - Degradation PY - 2016 SN - 9783981407648 VL - 2016 AN - OPUS4-38483 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Alterung von Elastomerdichtungen für Lagerbehälter N2 - Unsere Aufgabe im Fachbereich 3.4 der Bundesanstalt für Materialforschung und prüfung (BAM) ist die sicherheitstechnische Begutachtung von Transport- und Lagerbehältern für radioaktiven Abfall, die für langfristige Zwischenlagerung ausgelegt sind. Ein Arbeitsschwerpunkt ist die Bewertung der Lebensdauer von Metall- und Elastomerdichtungen in den Behältern im Hinblick auf die Anforderungen für langfristige Behältersicherheit (min. 40 Jahre in Deutschland). Um die Eigenschaftsänderungen der Elastomerdichtungen während einer beschleunigten Alterung über lange Zeiträume (bis zu fünf Jahre) untersuchen zu können, wurde ein Alterungsprogramm an ausgewählten Elastomeren (HNBR, EPDM, FKM) begonnen. Im Gegensatz zu Normalterungsverfahren altern wir keine Normteile, sondern O-Ringe im unverpressten sowie verpressten Zustand. Diese Vorgehensweise ermöglicht die Bewertung des Einflusses der Verpressung auf die Alterung sowie die Untersuchung des Bauteilversagens mittels Leckageratenmessungen unter anwendungsnahen Bedingungen. Weitere Charakterisierungsmethoden sind Härtemessung, dynamisch-mechanische Analyse (DMA), Thermogravimetrie (TGA), Druckspannungsrelaxation, Druckverformungsrest (DVR), Dichtebestimmung und Zugversuch. Das Ziel ist, die Leckagerate mit anderen Eigenschaften bzw. Methoden zu korrelieren, um so ein aussagekräftiges und leichter zu bestimmendes Lebensdauerkriterium für elastomere O-Ringe abzuleiten. Während der Alterung können in Abhängigkeit von Material sowie Alterungsdauer und –temperatur Inhomogenitäten aufgrund von diffusionsbegrenzter Oxidation auftreten, durch die sich unterschiedliche Eigenschaften an der Oberfläche und im Volumen der Dichtung ergeben, was zu falschen Lebensdauerabschätzungen führen kann. Mittels Mikrohärtemessung über den Querschnitt werden diese Effekte charakterisiert und bei der Extrapolation mittels Zeit-Temperatur-Verschiebung und Arrheniusgraph berücksichtigt. Bisher liegen Daten von bis zu einem Jahr bei vier verschiedenen Temperaturen (75 °C, 100 °C, 125 °C und 150 °C) gealterten Proben vor. Nach 100 Tagen bei 150 °C weisen HNBR und EPDM schon einen DVR von über 80 % auf, aber noch keinen signifikanten Anstieg der Leckagerate. Diese sinkt zunächst während der Alterung, da die Permeabilität aufgrund von Vernetzungsreaktionen sinkt. Bei HNBR ist dies aufgrund der dominanteren Vernetzungsreaktionen während der Alterung noch stärker ausgeprägt als bei EPDM. T2 - Technomer 2015 - 24. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Germany DA - 12.11.2015 KW - Aging KW - Elastomer KW - Seal KW - Leakage KW - Compression PY - 2015 SN - 978-3-939382-12-6 SP - 43 CY - Chemnitz AN - OPUS4-35050 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Ageing of elastomeric seals for storage containers N2 - At BAM Federal Institute for Materials Research and Testing in Germany, it is our responsibility to audit the safety of casks designed for transport and/or storage of radioactive material. With regard to the requirements on long-term safety of the containers, it is necessary to evaluate the service lifetime of the elastomeric seals used in the containers. With ageing, the elastomers will gradually lose their elasticity and their ability for recovery, which might result in a leakage above the allowed level or in a release of radioactivity during an incident. It is important to know the rate of degradation and which property can be used as an practical and easily measurable end-of-lifetime criterion. For this reason, we devised ageing experiments on different kinds of elastomers, namely FKM, EPDM and HNBR. The former two are actually used in containers for radioactive wastes – either as auxiliary seal in casks containing high activity waste, or as main seal in casks for medium or low activity waste. The latter is an often used seal material that is tested for comparative reasons. In our ageing program, these three materials are aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) in order to extrapolate the data to service temperature using a suitable model. They are examined at logarithmic time intervals of several days up to 5 years. The samples are aged in their undeformed O-ring state as well as compressed between flanges with a deformation corresponding to the actual compression during service. Thus we can compare the ageing between relaxed and stressed sample. Additionally, we are ageing samples in flanges that allow leakage rate measurements. Other measurements include monitoring of the recovery force of the seal and the compression set. Furthermore, the samples are examined by thermal and dynamic-mechanical analysis for detecting changes in the glass transition temperature due to crosslinking or chain scission in the material. Besides, hardness is measured as a practical macroscopic indicator. Until now, we have analyzed samples aged up to 100 days. At the highest ageing temperature of 150 °C, the compressed EPDM has already reached a compression set of 95 %, while HNBR and FKM have reached 80 % and 30 %, respectively. Furthermore, HNBR has reached a Shore D hardness of 85, which is an immense increase after the initial value of 80 Shore A. However, when looking at the cross-section of the sample, it was obvious that only a layer of about 1 mm thickness has become so hard, while the inner part remained rubbery. This shows that there has been intense crosslinking mostly near the surface of the HNBR which forms a kind of oxygen diffusion barrier, inhibiting the thermooxidation of the inner part of sample which can retain elastic properties. In EPDM, the oxygen permeability is much greater, which leads to a more homogeneous degradation across the whole sample and thus resulted in a higher compression set. The low compression set of FKM shows the outstanding high-temperature properties of this material. T2 - Annual Meeting on Nuclear Technology 2015 CY - Berlin, Germany DA - 2015-05-05 KW - Elastomer KW - Rubber KW - Aging KW - Lifetime KW - Seal KW - Cask KW - Compression PY - 2015 SN - 978-3-926956-98-9 SP - 1 EP - 10(?) PB - INFORUM-Verl. u. Verwaltungsges. AN - OPUS4-33782 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Ageing of elastomeric seals for storage containers N2 - At BAM Federal Institute for Materials Research and Testing in Germany, it is our responsibility to evaluate the safety of casks designed for transport and/or storage of radioactive material. This includes the investigation of elastomeric seals applied in the containers. Besides examining the low-temperature behavior of elastomeric seals, it is our goal to evaluate the service lifetime of the seals with regard to the requirements for long-term safety (40 years and more) of the containers. Furthermore, we deem it necessary to exceed the requirements given in the ageing standard DIN 53508 and take into account diffusion-limited oxidation (DLO) effects and non-Arrhenius behavior when making lifetime predictions. Therefore, we started an ageing programme with selected rubbers (HNBR, FKM and EPDM) which are oven-aged at four different temperatures (75 °C, 100 °C, 125 °C and 150 °C) in order to extrapolate the data to service temperature using different models and check which one is appropriate. Samples are examined at different times up to 5 years. In order to be able to compare between compressed and relaxed rubber, they are aged in two conditions: the undeformed O-ring state as well as compressed between plates with a compression of 25 % corresponding to the actual compression during service. Additionally, we are ageing samples in flanges that allow leakage rate measurements which is the central performance criterion. Analysis methods include hardness as a quick indicator, compression set and compression stress relaxation as measures reflecting the actual properties of a compressed seal. Additionally, we are applying classical polymer analysis methods like dynamic mechanic analysis and thermogravimetric analysis which show changes in the polymeric structure due to chain scission and crosslinking. Furthermore, we are testing the leakage rate of the O-rings in order to correlate the changes in physical properties to the actual performance of the seal. First results of samples aged up to 100 days show a strong increase in hardness for HNBR, a moderate increase for EPDM and hardly a change for FKM. A similar result is seen in the compression set of samples aged 100 d at 100 °C in compression as HNBR has reached 60 %, EPDM 25 % and FKM 15 % compression set. However, after ageing at 150 °C, EPDM shows a worse performance with 95 % compression set compared to HNBR with only 80 %. This is probably due to DLO effects in HNBR that appear because of the fast ageing and low oxygen permeability in HNBR. This leads to a deficit of oxygen in the center of the sample which is thus protected from ageing and can retain elastic properties. The full paper shall discuss the changes in material properties observed to date and the impact on the performance of elastomeric seals. T2 - IRC 2015 - International rubber conference CY - Nürnberg, Germany DA - 29.06.2015 KW - Elastomer KW - Rubber KW - Aging KW - Lifetime KW - Seal KW - Cask KW - Compression PY - 2015 SP - 1 EP - 10 AN - OPUS4-34939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Characterisation of degradation and determination of end-of-lifetime criterion for O-ring seals N2 - The ageing of polymers, including elastomers, is an undesirable but inevitable process leading to a limited lifetime of rubber products such as seals. Independent of the application, as e.g. in automotive, piping or container applications, a long lifetime or at least a timely exchange of a seal before occurrence of critical failure is desired. In order to investigate the degradation of material properties and to determine the lifetime of elastomers used as seals, an ageing programme was started with hydrogenated acrylonitrile butadiene rubber (HNBR), ethylene propylene diene rubber (EPDM) and fluorocarbon rubber (FKM) [1-3]. Both O-ring seals (uncompressed and compressed by 25 %) with a cord diameter of 10 mm as well as sheets with a thickness of 2 mm were aged at 75 °C, 100 °C, 125 °C and 150 °C for up to two years. The changes of material properties during ageing were characterised for each material using samples from the sheets by means of e.g. Dynamic Mechanical Analysis and tensile tests, while sealing properties such as leakage rate were determined on O-rings. The experimental results indicate that while material properties show considerable degradation effects, the static leakage rate stays constant or even decreases before failure occurs quite suddenly at advanced degradation levels. This reveals that static leakage rate has only limited sensitivity for the degradation of the seal material. Our approach to determine a suitable end of lifetime criterion, which involves a partial decompression of the seal during the leakage test, is presented and discussed. T2 - RubberCon 2017 CY - Prague, Czech Republic DA - 23.05.2017 KW - Life time prediction KW - Ageing KW - Rubber seal KW - Leakage PY - 2017 SN - 978-80-906662-0-7 SP - 65 EP - 72 AN - OPUS4-40391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang A1 - Völzke, Holger T1 - Investigation of elastomer seal behavior for transport and storage packages N2 - Rubbers are widely used as main sealing materials for containers for low and intermediate level radioactive waste and as additional component to metal seals in spent fuel and high active waste containers. According to appropriate guidelines and regulations safe enclosure of the radioactive container contents has to be guaranteed for long storage periods as well as down to temperatures of -40 °C for transportation. Therefore the understanding of seal behavior is of high importance. In this paper we focus on the behavior of elastomer seals at low temperatures with regard to poten-tial decrease of leak-tightness. In addition, changes in material properties due to aging effects over long periods of time and their influence on the seal performance is investigated. It is known that material properties of rubbers are strongly temperature dependent. At low tempera-tures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cool-ing, the material changes from rubber-like entropy-elastic to stiff energy-elastic behavior, that al-lows nearly no strain or retraction due to the glass transition. Hence rubbers are normally used above their glass transition but the minimum working temperature limit is not defined precisely. Aging of elastomer seals is important, as possible dynamic loads may have to be considered during the whole interim storage period (so far approved in Germany for up to 40 years) and for transporta-tion after storage. For the investigations, fluorocarbon (FKM) and ethylene-propylene-diene (EPDM) rubbers were selected as they are often used in radioactive waste containers. Some materials were purchased from a commercial seal producer and some materials were compounded and cured at BAM. The elastom-ers where studied by several thermo-analytical methods and compression set to characterize the material behavior at low temperatures. Additionally component tests were performed to determine the breakdown temperature of the sealing function of complete elastomer O-rings. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 PY - 2013 SP - Paper 227, 1 EP - 8 PB - Omnipress AN - OPUS4-30377 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang ED - Riedl, A. T1 - Was passiert bei tiefen Temperaturen? - Dichtungsverhalten im Bereich des Glasübergangs N2 - Elastomere werden vielfach als Dichtungsmaterial für verschiedene Anwendungen eingesetzt. In vielen Bereichen ist die Funktion der Dichtung auch bei tiefen Temperaturen erforderlich. Daher ist das Verständnis des Versagensmechanismus von großer Bedeutung. Normalerweise werden Elastomere oberhalb ihres Glass-Gummi Umwandlungsbereiches eingesetzt, wobei die minimale Einsatztemperatur nicht exakt definiert ist. Daher ist es sinnvoll, diese untere Temperatureinsatzgrenze in Abhängigkeit von den Materialeigenschaften zu bestimmen. Hierfür werden die Ergebnisse der thermischen Analyse mit den Resultaten des Druckverformungsrests aus einer abgewandelten Messung mit der Dynamisch Mechanischen Analyse (DMA) kombiniert. Weiterhin werden Ergebnisse von Bauteilversuchen vorgestellt und diskutiert. Die vorgestellten Untersuchungen wurden zum großen Teil auf Untersuchungen im Rahmen der Dissertation von M. Jaunich durchgeführt. T2 - XVIII. Dichtungskolloquium - Sichere und zuverlässige Dichtverbindungen CY - Rheine, Germany DA - 25.09.2013 KW - Dichtung KW - Glasübergang KW - Elastomer KW - Druckverformungsrest PY - 2013 SN - 978-3-8027-2216-5 SP - 51 EP - 58 PB - Vulkan AN - OPUS4-29221 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang T1 - Tieftemperaturverhalten von Elastomerdichtungen - Eigenschaftsbestimmung für den Einsatz in Transport- und Lagerbehältern für radioaktive Stoffe N2 - Die Messung des dynamischen Speichermoduls mit der Dynamisch-Mechanischen-Analyse ermöglicht einen schnellen Überblick über das temperaturabhängige Verhalten von elastomeren Dichtungsmaterialien. Ein direkter Rückschluss von der so ermittelten Glasübergangstemperatur Tg auf die Versagenstemperatur einer Dichtung ist aber ohne zusätzliche Messungen bisher nicht möglich. Mit den Ergebnissen des Druckverformungsrestes DVR und des DVRDMA ist eine ge-nauere Beschreibung der Tieftemperatureigenschaften und dadurch der Funktion von elastomeren Dichtungsmaterialien möglich. Messungen ergeben beispielsweise, dass sich das EPDM bei einer Temperatur von -40 °C laut der Dynamisch Mechanischen Analyse noch im gummielastischen Bereich befindet. Die DVRDMA-Werte zeigen eine Rückstellung um mehr als 40 % der Ausgangsdeformation in wenigen Minuten. Mit derart detailliert bestimmten Eigenschaften lassen sich Rückschlüsse auf einsatzspezifische Anforderungen wie z. B. die Dichtwirkung in Abhängigkeit von Betriebstemperatur und mechanischer Belastungsgeschwindigkeit ziehen, so dass je nach Einsatzbedingungen für die Dichtungen eine geeignete Materialauswahl getrof-fen werden kann. T2 - Jahrestagung Kerntechnik 2010 CY - Berlin, Deutschland DA - 2010-05-04 KW - Dichtungen KW - Elastomere KW - Tieftemperaturverhalten PY - 2010 IS - Sektion 5 / 503 SP - 1 EP - 4 CY - Berlin AN - OPUS4-21272 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang T1 - Low temperature properties of rubber seals - results of component tests T2 - 10th Fall rubber colloquium CY - Hannover, Germany DA - 2012-11-07 PY - 2012 SN - 978-3-9814076-1-7 IS - khk2012_jaunich.pdf SP - 1 EP - 8 AN - OPUS4-26995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Stark, Wolfgang T1 - Investigating low temperature properties of rubber seals N2 - To achieve the required tightness levels of Containers for low and intermediate level radioactive wastes rubbers are widely applied as main sealing materials. The save encapsulation of the radioactive Container contents has to be guaranteed according to legislation and appropriate guidelines for long storage periods as well as down to temperatures of-40 °C during transportation. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of rubbers are strongly influenced by temperature. At low temperatures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cooling the material changes from rubber-like entropy-elastic to stiff energy-elastic behaviour, that allows nearly no strain or retraction. Therefore, rubbers are normally used above their glass transition but the minimum working temperature limit is not defrned precisely, what can cause problems during application. The temperature ränge where full functionality is possible is strongly dependent on the application conditions and the material. For this investigation mainly ethylene propylene diene (EPDM) and fluorocarbon rubbers (FKM) were selected as they are often used for radioactive waste Containers. Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) are typically used for the determination of the temperature ränge of the glass transition process. The standardized compression set measurement according to ISO 815 is common for investigation of rubber sealing materials as the test simulates the seal behaviour after release. To reduce the test time of the Standard tests a faster technique giving the same information was developed. Additionally, the breakdown temperature of the sealing function of complete O-ring seals is measured in a component test Setup to compare it with the results of the other tests. The experimental Setup is capable of measuring the leakage rate at low temperatures by the pressure rise method. A model was developed that allows calculating the minimum working temperature limit of a seal by combining the results of the applied methods. T2 - WM2013 Conference CY - Phoenix, Arizona, USA DA - 24.02.2013 PY - 2013 SN - 978-0-9836186-2-1 SP - 1 EP - 12 CY - Phoenix, Arizona, USA AN - OPUS4-28853 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Untersuchungen an Elastomerdichtungen - Tieftemperatur und Alterung N2 - Ziel unserer Arbeit ist es, den sicheren Einschluss von gefährlichen Gütern in entsprechenden Verpackungen (z.B. Behälter für radioaktive Stoffe) unter verschiedenen Umgebungsbedingungen und über lange Zeiten sicher zu stellen bzw. die Materialauswahl entsprechend zu steuern. Aufgrund ihrer einfachen und zuverlässigen Anwendung werden Elastomere für viele Dichtungsaufgaben eingesetzt. In vielen Anwendungsbereichen wie z.B. Verkehr, Luftfahrt und Verfahrenstechnik können während des Einsatzes tiefe Temperaturen auftreten, bei denen die Funktionsfähigkeit der Dichtung erhalten bleiben muss. Daher ist die Untersuchung des Verhaltens von Elastomerdichtungen bei tiefen Temperaturen wichtig, um ihren Temperatureinsatzbereich nach unten abzugrenzen und dadurch einen verlässlichen Betrieb zu sichern. Dazu wurden umfangreiche Untersuchungen durchgeführt, auf deren Ergebnisse hier kurz eingegangen werden soll. Bei allen Anwendungen ist die Frage nach der Lebenszeit einer Dichtung entscheidend für z.B. Austauschintervalle oder Wartung. Besondere Bedeutung hat die Lebensdauer allerdings bei Anwendungen, in denen ein Austausch der Dichtung nicht möglich ist. Hier kann die Dichtung über die Lebensdauer des Gesamtsystems entscheiden. Daher ist eine verlässliche Abschätzung der Lebensdauer für diese Anwendungen relevant. Dazu ist eine umfangreiche Datenbasis erforderlich. Entsprechende Arbeiten, die gerade begonnenen worden sind, sollen ergänzend vorgestellt werden. Erste konkrete Ergebnisse werden im Vortrag vorgestellt. T2 - PolyMerTec 14 CY - Merseburg, Germany DA - 25.06.2014 PY - 2014 SP - 313 EP - 318 AN - OPUS4-32151 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Low temperature properties of rubber seals - influence of gamma irradiation N2 - Rubbers are widely used as sealing material in various applications. In many fields, the function of seal materials at low temperatures is required. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. KW - Compression set KW - Irradiation KW - O-ring KW - Seal PY - 2014 SN - 978-3981407624 SP - 1 EP - 7 AN - OPUS4-32326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar ED - Van Breugel, K. ED - Koenders, E.A.B. T1 - Approach for the investigation of long-term behaviour of elastomeric seals for transport and storage packages N2 - Elastomers are widely used as main sealing materials for Containers for low and intermediate Ievel radioactive waste and as additional component to metal seals in spent fuel and high active waste Containers. According to appropriate guidelines and regulations safe enclosure of the radioactive Container contents has to be guaranteed for long storage periods as well as down to temperatures of -40 °C for transportation. Therefore the understanding of seal behaviour in general is of high importance and ageing of elastomeric seals has to be considered with regard to possible dynamic events taking possibly place during transport after storage. T2 - 1st Ageing of materials & structures 2014 conference CY - Delft, The Netherlands DA - 26.05.2014 KW - O-Ring KW - Seal KW - Ageing KW - Elastomer KW - Compression set PY - 2014 SN - 978-94-6186-313-3 SP - 87 EP - 93 AN - OPUS4-30820 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Weber, Mike A1 - Kömmling, Anja A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Völzke, Holger T1 - Performance of elastomer seals in transport and storage casks N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste and for spent fuel transportation casks. In addition, they are also used for spent fuel storage and transportation casks (dual purpose casks (DPC)) as auxiliary seals to allow leakage rate measurements of metal barrier seals for demonstration of their proper assembling conditions. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with regard to mechanical, thermal, and environmental conditions as well as irradiation during the entire operation period. Concerning DPC, degradation effects should be limited in a way that, for example, effects from potentially released decomposition elements may not harm e.g. metal barrier seals. Leakage rate measurements should be possible also after long interim storage periods prior to subsequent transportation. Because of the complex requirements resulting from the various applications of containers for radioactive waste and spent nuclear fuel, BAM has initiated several test programmes for investigating the behaviour of elastomer seals. In this contribution the current status is described and first results are discussed. T2 - International conference on management of spent fuel from nuclear power reactors: An integrated approach to the back end of the fuel cycle CY - Vienna, Austria DA - 15.06.2015 KW - Ageing KW - Elastomer KW - Glass-rubber transition KW - Irradiation KW - Material model PY - 2015 SP - 1 EP - 8 AN - OPUS4-33553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Stark, Wolfgang T1 - Understanding low temperature properties of elastomer seals N2 - Elastomers are widely used as the main sealing materials for containers for low and intermediate level radioactive waste and as an additional component to metal seals in spent fuel and high active waste containers. The safe encapsulation of the radioactive container inventory has to be guaranteed according to regulation and appropriate guidelines for long term storage periods as well as for temperatures as low as -40°C during transport. Therefore, the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of elastomers are strongly temperature dependent. At low temperatures, this is caused by the rubber-glass transition (abbreviated: glass transition). During continuous cooling, the material changes from a rubber-like entropy elastic to a stiff energy elastic behaviour, which allows nearly no strain or retraction. Hence, rubbers are normally used above their glass transition, but the minimum working temperature limit is not defined precisely; this can cause problems during the above noted applications. Therefore, the lower operation temperature limit of elastomer seals must be determined in dependence of the material properties. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) are combined with standardised measurements to determine the compression set according to ISO 815. To reduce the test time of the standard tests, a faster technique than normally used was developed. Additionally, the breakdown temperature of the sealing function of complete O ring seals was measured in a component test set-up to compare it with the results of the other tests. The experimental set-up is capable of measuring the leakage rate at low temperatures by the pressure rise method. A fluorocarbon rubber (FKM) was selected for this investigation as it is often used for radioactive waste containers. The materials (seals and test sheets) were purchased from a commercial seal producer. KW - Sealing material KW - Elastomer KW - Compression set KW - Dynamic mechanical analysis KW - Low temperature behaviour PY - 2011 U6 - https://doi.org/10.1179/1746510911Y.0000000004 SN - 1746-5095 SN - 1746-5109 SN - 0957-476X VL - 22 IS - 2 SP - 83 EP - 88 PB - Ramtrans Publ. CY - Ashford AN - OPUS4-24015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Stark, Wolfgang T1 - Understanding the low temperature properties of rubber seals N2 - Rubbers are widely used as main sealing materials for containers for low and intermediate level radioactive waste and as additional component to metal seals in spent fuel and high active waste containers. The save encapsulation of the radioactive container inventory has to be guaranteed according to legislation and appropriate guidelines for long term storage periods as well as down to temperatures of -40 °C during transport. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of rubbers are strongly temperature dependent. At low temperatures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cooling the material changes from rubber-like entropy-elastic to stiff energy-elastic behaviour, that allows nearly no strain or retraction, due to the glass transition. Hence rubbers are normally used above their glass transition but the minimum working temperature limit is not defined precisely, what can cause problems during application. Therefore the lower operation temperature limit of rubber seals should be determined in dependence of the material properties. The results of Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) are combined with the results of standardized measurements as the compression set according to ISO 815. To reduce the test time of the standard tests a faster technique was developed. Additionally, the breakdown temperature of the sealing function of complete O-ring seals is measured in a component test setup to compare it with the results of the other tests. The experimental setup is capable of measuring the leakage rate at low temperatures by the pressure rise method. A fluorocarbon rubber (FKM) was selected for this investigation as it is often used for radioactive waste containers. Some materials (seals and test sheets) were purchased from a commercial seal producer and some materials were compounded and cured at BAM in form of rubber sheets. T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 KW - Dichtungen KW - Elastomere KW - Tieftemperaturverhalten PY - 2010 SP - 1 EP - 7 (Session T41 / Paper 169) AN - OPUS4-23887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Low temperature - For a seal this depends on the applied material T2 - DKT 2012 - German Rubber Conference CY - Nuremberg, Germany DA - 2012-07-02 PY - 2012 IS - 10-2330_5-L-1530 SP - 1 EP - 4 PB - Deutsche Kautschuk-Gesellschaft CY - Frankfurt am Main AN - OPUS4-26190 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Behaviour of rubber seals at low temperatures - results of component tests - N2 - The investigation of low temperature properties of elastomeric sealing materials by means of thermo-analytical methods is a sound way to get information about the glass transition process. The breakdown temperature of the sealing function of O-ring seals was measured in a component test setup depending on material and degree of compression. An in depth explanation of the observed component tests behaviour is currently in preparation. It requires the results of thermo-analytical methods and measurements as the compression set (not shown here). With that, a model was developed to describe the correlation between physical material parameters and observed component behaviour. T2 - Jahrestagung Kerntechnik 2013 CY - Berlin, Germany DA - 14.05.2013 PY - 2013 SP - 1 EP - 6 AN - OPUS4-28574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Druckverformungsrest bei tiefen Temperaturen N2 - Für Elastomenwerkstoffe im Allgemeinen und im Bereich der Dichtungstechnik im Besonderen ist der Druckverformungsrest eine wichtige Kenngröße zur Beurteilung der Eignung eines Werkstoffs bzw. der Funktion eines Bauteils. Er ermöglicht eine Einschätzung des zeitabhängigen Rückstellverhaltens eines Werkstoffs nach Deformation. Dieses ist für Dichtungen von besonderer Bedeutung, da der Test deren Einbauzustand nachstellt. Oft wird er, bei der Prüfung unter erhöhten Temperaturen, zur Beurteilung des Alterungsverhaltens verwendet und kann anhand eines definierten Versagenskriteriums zur Lebensdauerabschätzung eingesetzt werden. Bei tiefen Temperaturen dient er dazu, die limitierende Einsatztemperatur zu bestimmen. Dabei spielt eine Alterung im eigentlichen Sinne nur eine untergeordnete Rolle, wohl aber physikalische Effekte wie Tieftemperaturkristallisation und Glasübergang. Diese Effekte sind weit weniger durch lange Lagerzeiten beeinflusst als die eigentliche Alterung. Die Versuchsdurchführung unterscheidet sich je nach angewandter Norm und kann einen deutlichen Einfluss auf den Druckverformungsrest haben. Alle standardisierten Methoden sind aufgrund der langen Lagerzeiten relativ langwierig und erfordern das regelmäßige Eingreifen durch den Prüfer. Zusätzlich sehen einige Methoden nur die Bestimmung eines einzelnen Wertes nach einer definierten Zeit vor. Um die Messungen zu beschleunigen wurde eine Methode entwickelt, die automatisch die erforderlichen Messungen bei mehreren Temperaturen durchführt. Dazu wird ein Prüfgerät der Dynamisch Mechanischen Analyse verwendet, das kontinuierlich die Deformation während eines frei programmierbaren Temperaturzyklus misst, wodurch eine sehr große Datenmenge verfügbar ist. Ein Vergleich der neuen Methode mit den Ergebnissen des nach ISO 815 genormten Messprinzips ergibt eine gute Übereinstimmung. Ergebnisse der neuen Methode werden vorgestellt und die Vorzüge der kontinuierlichen Datenerfassung, z.B. für die Materialauswahl, diskutiert. Die vorgestellten Ergebnisse beziehen sich zum großen Teil auf die in beschriebenen Untersuchungen und Ergebnisse. T2 - Technomer 2013 - 23. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Germany DA - 14.11.2013 PY - 2013 SN - 978-3-939382-11-9 IS - Kapitel V 3.4 SP - 1 EP - 8 AN - OPUS4-29616 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Low temperature properties of rubber seals T2 - 9th Fall rubber colloquium CY - Hannover, Germany DA - 2010-11-03 KW - Dichtungen KW - Elastomere KW - Tieftemperaturverhalten PY - 2010 SN - 978-3-9814076-0-0 SP - 175 EP - 178 AN - OPUS4-22331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Material behaviour of static seals at low temperatures T2 - 17th ISC - International sealing conference CY - Stuttgart, Germany DA - 2012-09-13 PY - 2012 SN - 978-3-00-039198-9 IS - A 16 SP - 295 EP - 300 CY - Frankfurt/M. AN - OPUS4-26524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Druckverformungsrest bei tiefen Temperaturen N2 - Der Druckverformungsrest (DVR) stellt insbesondere für Dichtungsanwendungen eine wichtige Kenngröße zur Beurteilung der Eignung eines Elastomers dar. Er ermöglicht die Einschätzung des zeitabhängigen Rückstellverhaltens eines Werkstoffs nach Deformation. Neben der Prüfung bei erhöhten Temperaturen, zur Beurteilung des Alterungsverhaltens, lässt sich bei der Durchführung bei tiefen Temperaturen die limitierende Einsatztemperatur bestimmen. Die Versuchsdurchführung unterscheidet sich je nach angewandter Norm und kann einen deutlichen Einfluss auf den DVR-Wert haben. Um bei tiefen Temperaturen eine schnelle Aussage zu gestatten, ist eine im Vergleich zu genormten Methoden deutlich schneller durchzuführende, automatisierte Methode entwickelt und mit Standardmethoden verglichen worden. Durch kontinuierliche Messung des Druckverformungsrests kann die Kinetik der Materialrückstellung betrachtet und dadurch ein effizienter Materialvergleich und eine effiziente Materialauswahl ermöglicht werden. Compression set (CS) is especially for sealing applications an important parameter for material selection. It allows an assessment of the time dependent recovery after deformation. In addition to testing at elevated temperatures which aims at the evaluation of the ageing behaviour, testing at low temperatures permits the determination of the low working temperature limit. The test procedure varies depending on the applied standard and can show a significant effect on the CS value. In order to allow a quick statement regarding low temperatures an automated procedure being significantly faster realisable in relation to the standardised methods has been developed and compared with standard procedures. Continuous measurement of the compression set allows evaluating the recovery kinetics and therefore an efficient comparison and selection of materials. KW - Druckverformungsrest KW - Elastomere KW - Dichtung KW - O-Ring PY - 2014 SN - 0176-1625 VL - 67 IS - 8 SP - 487 EP - 491 PB - Gupta CY - Ratingen AN - OPUS4-31572 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Properties of elastomeric seals at low temperature T2 - International rubber conference (IRC 2009) CY - Nürnberg, Germany DA - 2009-06-29 PY - 2009 IS - Poster 23 SP - 1 EP - 3 AN - OPUS4-19611 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Messung des Tieftemperaturverhaltens von Elastomer-Dichtungen T2 - TECHNOMER 2009 - 21. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Deutschland DA - 2009-11-12 KW - Dichtungen KW - Elastomere KW - Tieftemperaturverhalten PY - 2009 SN - 978-3-939382-09-6 IS - ETV7 SP - 1 EP - 9 AN - OPUS4-20386 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Stark, Wolfgang A1 - Hoster, B. T1 - In-situ vulcanization monitoring by ultrasonic wave propagation T2 - 8. Kautschuk-Herbst-Kolloquium CY - Hannover, Deutschland DA - 2008-11-26 KW - Vulcanization KW - Cure monitoring KW - Ultrasound PY - 2008 SP - 133 AN - OPUS4-18574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Schulz, Sebastian A1 - Stark, Wolfgang A1 - Wolff, Dietmar T1 - Characterization of the low temperature behaviour of rubber sealing materials N2 - Rubbers are often used for seal applications due to their special material properties and easy use. In many applications the material is exposed to low temperatures during Operation. Therefore it is important to know the material behavior at low temperatures to determine the temperature ränge that allows a Safe Operation of the seal, e.g. in storage and transport Containers for radioactive materials. The seal function of an elastomer is limited in temperature by the rubber-glass transition during which the material properties change from rubber-like to stiff and glass-like. For a given application this correlation is not trivial and therefore needs an in-depth investigation under consideration of the physical properties and the application conditions. In this work different analytical methods are used to characterize the material behavior at low temperature in the ränge of the glass-rubber-transition and are compared with the quality of Operation of a component which is here defined by the detected leakage rate. T2 - Technomer 2011 - 22. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Deutschland DA - 10.11.2011 PY - 2011 SN - 978-3-939382-10-2 IS - Kap. 3.7 SP - 1 EP - 4 AN - OPUS4-24971 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jaunich, Matthias A1 - Probst, Ulrich A1 - Schulz, Sebastian A1 - Wolff, Dietmar A1 - Stark, Wolfgang ED - Berger, K.-F. ED - Kiefer, S. T1 - Elastomere - Untersuchung des Tieftemperaturverhaltens im Dichtungseinsatz N2 - Aufgrund ihrer einfachen und zuverlässigen Anwendung werden Elastomere für viele Dichtungsaufgaben eingesetzt. In vielen Anwendungsbereichen, wie z.B. Verkehr, Luftfahrt und Verfahrenstechnik, können während des Einsatzes tiefe Temperaturen auftreten, bei denen die Funktionsfähigkeit der Dichtung erhalten bleiben muss. Daher ist die Untersuchung des Verhaltens von Elastomerdichtungen bei tiefen Temperaturen wichtig, um ihren Temperatureinsatzbereich nach unten abzugrenzen und dadurch einen verlässlichen Betrieb zu sichern. Ziel dieser Arbeit ist es, den sicheren Einschluss von gefährlichen Gütern unter verschiedenen Umgebungsbedingungen und über lange Zeiten zu ermöglichen bzw. die Materialauswahl entsprechend zu steuern. KW - Dichtung KW - Druckverformungsrest KW - Elastomer KW - Glasübergang PY - 2013 SN - 978-3-9811509-7-1 SP - 82 EP - 91 CY - Mannheim AN - OPUS4-29661 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -