This work developed a computational methodology to evaluate and compare standard fire exposures such as those outlined in ASTM E119 with real fire exposures and determine the difference in the temperature rise of a rail car floor assembly. The real fire exposures simulated in this work were identified in a review of incidents and consisted of a constantly‐fed diesel fuel spill, a localized trash fire, and a gasoline spill simulated from a collision of the railcar with an automobile. These realistic fire exposures were applied to a variety of exemplar rail cars representative of single‐level and bi‐level passenger cars. These floor assembly models exposed to realistic fires were simulated in Fire Dynamics Simulator (FDS). The thermal exposure at the underside of railcar provided by FDS was coupled with a thermal model in ABAQUS, which provided the evolution of temperature in different components of the floor assembly. The standard scenarios were simulated for 2 hours instead of the typical 30 minutes to identify the appropriate exposure duration in ASTM E119, which can better represent a real fire scenario. The average and maximum temperatures predicted at the unexposed surface for both scenarios were compared with the threshold values given in NFPA 130.

中文翻译：

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根据轨道车辆地板组件的热响应评估标准和实际火灾暴露

这项工作开发了一种计算方法，用于评估和比较标准ASTM E119中所述的标准火灾暴露与实际火灾暴露，并确定轨道车辆地板组件温升的差异。在对事故的回顾中，确定了这项工作中模拟的真实火灾暴露，包括不断进食的柴油泄漏，局部垃圾大火以及有轨车与汽车碰撞所模拟的汽油泄漏。这些现实的火灾暴露被应用于代表单层和双层客车的各种示例性轨道车辆。这些暴露在现实火灾中的地板装配体模型是在Fire Dynamics Simulator（FDS）中进行仿真的。FDS提供的在铁路车底侧的热暴露与ABAQUS中的热模型相结合，这提供了地板组件不同组件中温度的变化。在ASTM E119中模拟了标准情景2个小时，而不是典型的30分钟，以识别适当的暴露持续时间，它可以更好地表示真实的火灾情景。将两种情况下未暴露表面上预测的平均和最高温度与NFPA 130中给出的阈值进行了比较。