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Organisationseinheit der BAM
- 3 Gefahrgutumschließungen; Energiespeicher (10)
- 3.1 Sicherheit von Gefahrgutverpackungen und Batterien (6)
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- 6 Materialchemie (2)
- 6.1 Oberflächen- und Dünnschichtanalyse (2)
- 6.2 Material- und Oberflächentechnologien (2)
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Paper des Monats
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Leakage testing during lateral displacement of metallic seals under mechanical accident impact
(2013)
In context with approval design tests, the IAEA regulations for the safe transport of radioactive material specify tests for demonstrating ability to withstand normal and accident conditions of transport. For 9-m drop test onto an unyielding target the drop orientation of the package must be chosen in a manner so that maximum damage occurs with regard to the safety criteria.
With respect to leak tightness after drop test impacts a horizontal or slap-down orientated test model can cause a lateral displacement of the packaging’s lids, affecting the leakage rate of the closure lid system strongly.
In Germany dual purpose casks with double lid sealing system composed of primary and secondary lid with bolts, metallic seals as well as cask body sealing surfaces are mainly used. Besides free drop tests with full-scale and half-scale models within licensing approval procedure BAM develops experimental testing methods to simulate defined stresses and deformations by means of components testing.
In order to investigate the relation between lateral lid displacement and leakage rate, BAM performs impact tests with small scaled flange-lid systems of transport packages in a drop test machine for guided drop tests.
The test setup is realized in a way that the flange part is fixed while a drop weight is impacting onto the lid’s edge. The dynamic displacement of the lid is measured simultaneously. Because of capturing the drop weight after first impact during a short rebound phase by pneumatic arrest mechanism a secondary impact on lid’s edge is excluded. The guided drop tests were accompanied by various measurements such as leakage rate recording during and after impact, identification of lateral shifting by electro-optical displacement transducer as well as decelerations of the lid and the impacting weight.
This paper describes the test setup, the test and measurement techniques as well as first results concerning the relation between lateral lid displacement and leaktightness.
In context with new cask designs and their approval procedure, the experimental testing of impact limiters under drop test conditions becomes more and more important in order to assess the damage mechanics behaviour and safety margins for validation reasons. In recent years, various designs of impact limiters have been tested by the Federal Institute for Materials Research and Testing within specific component testing and particularly with regard to type B package design approval procedures. The paper focuses on the experimental realisation of impact limiter tests and presents implemented measurement techniques to determine the amount of deformation and to explain the impact behaviour by means of photogrammetric metrology and three-dimensional fringe projection method, high speed motion analysis and adjusted deceleration measurements.
In context with new cask designs and their approval procedure the experimental testing of impact limiters under drop test conditions becomes more and more important in order to assess the damage mechanics behavior and safety margins for validation reasons.
In recent years various designs of impact limiters have been tested by the Federal Institute for Materials Research and Testing (BAM) within specific component testing and particularly with regard to type B package design approval procedures.
The paper focuses on the experimental realization of impact limiter tests and presents implemented measurement techniques to determine the amount of deformation and to explain the impact behavior by means of photogrammetric metrology and 3-d fringe projection method, high-speed motion analysis and adjusted deceleration measurements.
The mechanical and geometrical properties of impact targets greatly influence the outcome of a drop test. The International Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) as well as ISO 2248 describe the characteristics of impact targets for drop tests of dangerous goods packagings.
According to these regulations, the impact target’s surface needs to be unyielding, under testing conditions non-deformable, flat, and integral with a mass at least 50 times that of the heaviest packaging to be tested. The problem is that many production facilities, especially manufacturers of corrugated fibreboard boxes, do not have their own testing device with the required 50 times mass ratio of the impact target for a regulation compliant drop test during series production. Furthermore, at UN level it is considered necessary to revise these requirements.
In the present paper, the impact target requirements are examined in detail and compared with those in other technical areas (e.g., impact target for container for the transport of radioactive materials). A research method is being developed to investigate the dependency between the mass ratio of the packaging and the target as well as the damage resistance of a drop tested package in relation to specific design characteristics. The results are of high relevance for industry purposes and intended to ensure a uniform level of safety assessment for the mechanical testing of dangerous goods packagings.
For dangerous goods packagings, drop testing onto an essential unyielding target can be used to assess the mechanical resistance to impact loads. Adopted regulations like ADR/RID require that the impact surface provided shall be integral with a mass at least 50 times than that of the heaviest package to be tested. The problem is that many manufacturers do not possess impact targets that satisfy the required 50 times mass ratio for regulative drop tests during series production. The objective of this work is to verify existing and define improved criteria for impact target structures based on systematic investigations. Previous evidence highlights the relevance of other parameters in addition to the mass ratio. Therefore, in this research, a variation of drop test parameters was carried out experimentally. Furthermore, numerical vibration analysis was applied to investigate the deformability of the impact surface. The results conclude that the mass ratio of 1:50 cannot be defined as a decisive criterion. In order to determine the influence of further drop test parameters, the research findings were used to validate a parametric model which assesses impact target deflection. An approximation quality of over 90 % was achieved. As a result, new evaluation criteria are proposed. Firstly, a method for identifying critical impact target designs is provided. Secondly, a new comprehensive formula compares the approximated maximum deflection of a real impact target to the respective theoretical threshold derived from a worst-case assumption. In practice, this leads to great advantages in the evaluation of already installed impact targets for dangerous goods packagings.
For dangerous goods packagings, drop testing onto an essential unyielding target can be used to assess the mechanical resistance to impact loads. Adopted regulations like ADR/RID require that the impact surface provided shall be integral with a mass at least 50 times than that of the heaviest package to be tested. The problem is that many manufacturers do not possess impact targets that satisfy the required 50 times mass ratio for regulative drop tests during series production. The objective of this work is to verify existing and define improved criteria for impact target structures based on systematic investigations. Previous evidence highlights the relevance of other parameters in addition to the mass ratio. Therefore, in this research, a variation of drop test parameters was carried out experimentally. Furthermore, numerical vibration analysis was applied to investigate the deformability of the impact surface. The results conclude that the mass ratio of 1:50 cannot be defined as a decisive criterion. In order to determine the influence of further drop test parameters, the research findings were used to validate a parametric model which assesses impact target deflection. An approximation quality of over 90 % was achieved. As a result, new evaluation criteria are proposed. Firstly, a method for identifying critical impact target designs is provided. Secondly, a new comprehensive formula compares the approximated maximum deflection of a real impact target to the respective theoretical threshold derived from a worst-case assumption. In practice, this leads to great advantages in the evaluation of already installed impact targets for dangerous goods packagings.
Packagings for the transport of dangerous goods need to meet special requirements to get an approval. This includes free fall drop testing onto an essentially unyielding surface as a means to assess a package’s resistance to mechanical damage. A main requirement for drop tests is that the impact target’s mass shall be at least 50 times that of the heaviest package to be tested. Nevertheless, many manufacturers do not possess foundation structures with the required mass ratio. Previous evidence highlights that the mass ratio is not a decisive criterion on its own. Parameters such as the impact target foundation’s connection and the impulse experienced by the impacting object are essential as well. However, these factors are not easily verifiable since experimental measurements are not possible at most facilities. The objective of this work is to provide a detailed analysis on the interaction between impact target foundation and subgrade in dynamic impact testing using validated finite-element (FE) models. This research is highly beneficial for industrial application since it allows manufacturers to make informed predictions about the mechanical response of installed impact target foundations.
Due to the high damping mechanical properties of fiberboard materials, corrugated fiberboard boxes are widely used as transport packagings of dangerous goods. Since there is risk of vertical impact within the distribution system, drop tests are performed as design type tests to assess a package’s ability to withstand damage. In this context, however, little is known regarding the transient mechanical response of a filled fiberboard box. The reason is that the nature of the packaging material presents challenges in identifying the deformation mechanisms experimentally. The aim of this work is to provide a framework for predicting the damage resistance of complete, filled corrugated fiberboard boxes which are ready for transportation. Therein, drop test finite-element simulations are used and validated by experimental results. These numerical calculation models are a valuable tool for virtual product development and contribute to the optimization of the design cycle.
In the approval process of dangerous goods packagings, drop tests onto a flat, essentially unyielding surface are used to assess resistance against mechanical damage. International adopted regulations like ADR and RID define filling good dependent drop heights and filling degrees whilst the user needs to define the maximum gross mass to be tested and approved. Maximum packaging gross mass is defined conservatively and not reached in practice. To meet the defined gross mass in testing, using additives is permitted. However, in some cases, additives are not desirable due to packaging design or filling substance properties. This leads to deviations from the initial gross mass definition. Hence, a certain drop height adjustment is necessary to achieve the required impact loading. Laboratories frequently adjust drop height assuming a perfectly elastic collision that is inaccurate. Appropriate adjustment is not trivial due to energy conversion processes, for example, plastic deformation. In this work, a test stand
Ermittlung dynamischer Kennwerte von Dämpferbeton für die Simulation des Beanspruchungsverhaltens
(2016)
Die Sicherheit und Integrität von Verpackungen radioaktiver Stoffe wird anhand von numerischen Berechnungen bewertet. Bei einem Anprall oder Absturz sind die mechanischen Beanspruchungen auf die Behälter auch von den Eigenschaften des Untergrunds abhängig. Um potentielle Gefahren während der Verladung zu minimieren, wird energieabsorbierender Dämpferbeton in den Handhabungsbereichen nuklearer Lager eingesetzt.
Zu einer umfassenden sicherheitstechnischen Analyse und Bewertung gehört die Berücksichtigung des Beanspruchungsverhaltens von Dämpferbeton. Hierfür ist ein numerisches Materialmodell notwendig, das in der Literatur bisher nicht vorlag. Die dafür notwendigen dynamischen Kennwerte sind in verschiedenen Druck- und Eindringversuchen ermittelt worden. Dazu wurden dynamische Druckversuche an würfelförmigen Prüfkörpern durchgeführt, sowie Eindringversuche mit unterschiedlichen Eindringkörpern und Dämpferbetonproben. Die experimentell ermittelten Kennwerte wurden verwendet, um ein Materialmodell für Dämpferbeton zu entwickeln und kritische Beanspruchungsszenarien numerisch zu berechnen. Um die Qualität des Materialmodells zu überprüfen, wurde ein realitätsnaher Fallversuch eines Behälters in Originalgröße auf ein lagertypisches Dämpferbetonfundament durchgeführt.
In dem Beitrag sollen die unterschiedlichen Untersuchungen zur Ermittlung dynamischer Kennwerte sowie deren Ergebnisse dargestellt werden. Gezeigt werden ebenso numerische Nachberechnungen einzelner Versuche sowie die ausführliche Berechnung des Fallversuchs im Originalmaßstab. Experimentelle und numerische Ergebnisse aus der Simulation werden hier gegenübergestellt.