Size effect on the fire resistance of multilayer composite floor structures

The current standard methods for evaluating the fire resistance of high-speed train floor structures involve large-scale experiments that incur significant costs. To explore the feasibility of reducing the scale of these structural fire resistance tests , this study develops a two-dimensional numerical simulation model to assess the fire resistance of multilayer floor structures. The model's accuracy and applicability are rigorously validated through various fire resistance experiments conducted at multiple scales. The study emphasizes the dynamic thermal response of high-speed train floor structures, demonstrating a clear correlation between structural scale and fire resistance. Notably, the times to thermal insulation failure and integrity failure of multilayer composite floor structures decrease progressively with increasing scale. This trend can be described by an exponential function. Additionally, the model is employed to examine the effect of the ratio of the exposed surface size to the actual material size on fire resistance, with larger ratios leading to more rapid fire resistance failures.