| Titre | Tank car fire failure assessment using combined models |
| Télécharger | Téléchargements |
| |
| Licence | Veuillez noter que la Licence du gouvernement
ouvert - Canada remplace toutes les licences antérieures. |
| Auteur | McKinley, J; Xue, J; Williams, B W ; Xu, S |
| Source | 2021, 49p.  Accès ouvert |
| Image |  |
| Année | 2021 |
| Séries alt. | Publication de Transports Canada (TP) TP 15493E |
| Éditeur | CanmetMATÉRIAUX |
| Document | publication en série |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Sujets | modèles; temperature; logiciel; méthode d'analyses par elements finis; pression; détermination des contraintes; déformation; fluage; Transport ferroviaire; Technologie des matériaux; Incendie; Accident
ferroviaire; Ingénierie; Sécurité publique; Sécurité ferroviaire; Sciences et technologie; Transport; Santé et sécurité |
| Illustrations | séries chronologiques; graphiques; diagrammes schématiques; organigrammes; modèles 3D; diagrammes 3D; tableaux |
| Programme | CanmetMATÉRIAUX Traitement des matériaux avancés |
| Diffusé | 2021 09 01; 2022 05 13 |
| Résumé | (Sommaire disponible en anglais seulement)
An accident involving a rail tank car transporting flammable liquids such as crude oil, natural-gas condensates, or ethanol creates the potential for a
pool fire. There have been a number of rail incidences in which flammable liquids have been involved. This presents a safety risk to the public and the environment. TDG would like to better understand the fire performance of rail tank cars to
evaluate the applicable safety standards and regulations and to ensure that they provide a high level of safety.
In order to investigate these concerns, TDG initiated research projects to investigate tank car failure at high temperature. From FY
2016/17 to 2018/19 CanmetMATERIALS (CMAT) conducted tensile and creep-rupture tests of TC 128B and ASTM 516 Grade 70, two of the most common steels used in manufacturing tank cars. During FY 2018/19 a constitutive material model that includes
temperature-driven (25 °C to 800 °C) material softening and creep was implemented in finite element (FE) analysis software to enable detailed analysis of tank cars and tank car failures at high temperatures. CMAT then developed an FE model using
specific tank car geometry to predict tank car failure under various pool fire conditions in 2018/19 and 2019/20.
CMAT had three main objectives for the 2020/21 fiscal year. These were to 1) Develop a simpler and faster engineering model for
calculating material failure and validate it against the existing FE model. 2) Run a series of pool fire scenarios using temperature and pressure data from CanmetENERGY using both Models. 3) Complete a comparison between AFFTAC, an established
program for predicting tank car failure in pool fires, and CMAT's models.
CMAT developed an effective and time efficient engineering method for calculating the time to failure of a tank car in a pool fire scenario and validated it against their FE
model. This model can be run in excel or other computational software. CMAT simulated 34 realistic pool fire scenarios in both their FE and engineering models. All cases survived at least 100 minutes. Only two cases resulted in failure within the 716
minutes run time. One failed due to a blocked PRV and one failed because it lacked thermal protection. These results demonstrate the importance of these key rail tank car safety systems.
Preliminary comparisons between CMAT's models and AFFTAC
demonstrated some differences. Both AFFTAC and CMAT's models describe the high temperature behaviour of tank car materials. They both can predict two failure modes; yield (plasticity) and creep. Both models are temperature dependent. As the
temperature increases the yield stress decreases. At higher temperatures creep deformation occurs more rapidly at a given stress level than at lower temperatures. The realistic fire scenarios presented above did not provide sufficient data for
comparing CMAT's models with AFFTAC. CMAT and AFFTAC produced different results in synthetic scenarios that were run for the purpose of comparison. Further investigation is recommended. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Ce rapport résume les résultats de l'évaluation des soudures actuelles en acier TC128B des wagons-citernes. Les coupons d'échantillonnage ont
été reçus d'un wagon-citerne DOT-117J. Le travail expérimental dans ce rapport comprenait la détermination, à partir d'une soudure longitudinale, de (i) la composition chimique, la microstructure et la microdureté (ii) la résistance à la traction et
les emplacements de rupture dans la plage de température de 23 °C à -60 °C, et (iii) les courbes de transition de Charpy. Les caractéristiques de rupture typiques des échantillons du métal d'apport à faible résilience (par essai Charpy) et les
fractions volumiques de ferrite aciculaire (FA) ont été caractérisées et discutées. Les résultats de la soudure longitudinale ont été comparés à ceux d'une soudure circonférentielle caractérisée précédemment à partir du même wagon-citerne, incluant
un essai Charpy mis à jour à -34 °C, et les principales conclusions sont présentées. |
| GEOSCAN ID | 330075 |
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