The increasing use of composite materials in aircraft cabins and structures poses significant challenges in order to maintain and improve the fire safety of aviation. In this work, the flammability characteristics of a commercial glass-fibre reinforced phenolic composite (GFRP) used for aircraft cabin partitions and furnishing are investigated experimentally. Thermogravimetric analysis under inert atmosphere at several heating rates provided information on the thermal decomposition process. The degradation process is modelled with one and two-step mechanisms using the Ozawa–Flynn–Wall iso-conversional method and the GPYRO numerical code which utilizes a genetic algorithm optimization scheme. The estimated activation energy and pre-exponential factor values, especially in the two-step case (77.18 and 104.69 kJ/mol and 2.60 × 10 6 and 3.19 × 10 6 min −1 for the first and the second step respectively), recover reasonably well the conversion degree and its derivative. Tests with a cone calorimeter (CC), performed at different incident heat fluxes, provided information on the reaction to fire characteristics of the material and the influence of the heat flux on the combustion process. In general, combustion proceeds in two stages, flaming and smoldering combustion. The CC results assisted by scanning electron microscopy photos provide information on the charring characteristics of the material. The critical heat flux for ignition and the corresponding ignition temperature are estimated, correlating heat fluxes with time to ignition. Thermally thin and thick models are considered, as well as a modified technique bridging the gap between these limit cases and therefore valid for thermally thin and thick but also intermediate conditions (more pertinent in the present case). The results for this latter approach are $$\dot{q}^{\prime\prime}_{ig,cr}$$ q ˙ i g , c r ″ ~ 20 kW/m 2 and T ig = 469°C, providing also complementing information on thermophysical properties, such as thermal diffusivity, α = 1.23 × 10 −7 m 2 /s, thermal conductivity, k = 0.325 W/(m K) and specific heat capacity, c = 1.330 kJ/(kg K). This work provides information on the reaction to fire characteristics of GFRP, but also on physical and flammability properties in a form suitable to be used in numerical codes, for the prediction of fire and evacuation scenarios. The influence of the reinforcement structure on the fire behaviour of the composite is also illustrated and discussed.

中文翻译：

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用于飞机应用的玻璃酚醛复合材料的锥形量热仪和热重分析

在飞机机舱和结构中越来越多地使用复合材料对维持和提高航空防火安全提出了重大挑战。在这项工作中，通过实验研究了用于飞机机舱隔板和家具的商用玻璃纤维增​​强酚醛复合材料 (GFRP) 的可燃性特性。在惰性气氛下以多种加热速率进行热重分析提供了有关热分解过程的信息。使用 Ozawa-Flynn-Wall 等转换方法和利用遗传算法优化方案的 GPYRO 数值代码，通过一步和两步机制对降解过程进行建模。估计的活化能和指数前因子值，特别是在两步情况下（77.18 和 104.69 kJ/mol 以及 2.60 × 10 6 和 3。19 × 10 6 min -1 分别用于第一步和第二步），相当好地恢复了转化度及其导数。使用锥形量热计 (CC) 进行的测试在不同的入射热通量下进行，提供了有关材料对火特性的反应以及热通量对燃烧过程的影响的信息。一般来说，燃烧分有焰燃烧和阴燃燃烧两个阶段进行。由扫描电子显微镜照片辅助的 CC 结果提供了有关材料炭化特性的信息。估计点火的临界热通量和相应的点火温度，将热通量与点火时间相关联。考虑了热薄和厚模型，以及缩小这些极限情况之间差距的改进技术，因此适用于热薄和厚以及中间条件（在当前情况下更相关）。后一种方法的结果是 $$\dot{q}^{\prime\prime}_{ig,cr}$$ q ˙ ig , cr ″ ~ 20 kW/m 2 和 T ig = 469°C，提供还补充了有关热物理特性的信息，例如热扩散率，α = 1.23 × 10 -7 m 2 /s，热导率，k = 0.325 W/(m K) 和比热容，c = 1.330 kJ/(kg K) . 这项工作提供了有关 GFRP 对火灾特性的反应的信息，以及适用于数字代码的形式的物理和可燃性特性，用于预测火灾和疏散场景。