This work examines the influence of a kerosene flame on the residual mechanical tensile properties of composite laminates manufactured by thermo-consolidation process from unidirectional (UD) carbon fibers and a Polyether Ketone Ketone (PEKK) thermoplastic. Considering laminates with two stacking sequences (orthotropic or quasi-isotropic - QI), the influence of a kerosene flame exposure (116 kW/m² and 1100 °C) on the composites structural integrity was examined as a function of exposure time (5-10-15min). The discussions on fire- and mechanically-induced damage mechanisms are supported by fractographic analysis of specimens. Not surprisingly, longer exposures to kerosene flame lead to gradually increasing damages within the laminates at different scales (micro-meso-macro), ultimately resulting in degrading the bearing capabilities of the material. With respect to virgin specimens, the axial strength decreases by almost 60 and 40% (after a 15min exposure) in orthotropic and QI laminates, respectively. At the same time, the axial stiffness is about 30 and 20% lower (after a 15min exposure). Contrary to orthotropic laminates, two well-defined areas are observed through the thickness in QI laminates: a severely degraded one and a virtually undamaged one. The first one corresponding to the exposed surface side is significantly damaged (fibers oxidation and pyrolysis of the PEKK matrix leading to an extensive delamination). The second one corresponding to the back-surface side is characterized by two plies with very little damage. When loaded in tension, the “undamaged” plies are characterized by the breakage of 0° fibers. This failure mechanism shows that these “undamaged” plies are capable to bear significant portions of the tensile loading contrary to orthotropic specimens in which extensive delamination prevails through the whole thickness.

这项工作检查了煤油火焰对由单向 (UD) 碳纤维和聚醚酮酮 (PEKK) 热塑性塑料通过热固结工艺制造的复合层压板的残余机械拉伸性能的影响。考虑到具有两个堆叠序列（各向异性或准各向同性 - QI）的层压板，煤油火焰暴露（116 kW/m ²和 1100 °C）对复合材料结构完整性的影响作为暴露时间（5- 10-15 分钟）。对火灾和机械引起的损伤机制的讨论得到了试样断口分析的支持。不足为奇的是，较长的暴露于煤油的火焰导致逐渐层压材料内的不同尺度增加的损害（微观-macro），最终导致材料的承载能力下降。对于原始样品，正交各向异性和 QI 层压板的轴向强度分别降低了近 60% 和 40%（暴露 15 分钟后）。同时，轴向刚度降低了约 30% 和 20%（暴露 15 分钟后）。与正交各向异性层压板相反，通过 QI 层压板的厚度观察到两个明确定义的区域：严重退化的区域和几乎未损坏的区域。对应于暴露表面侧的第一个明显损坏（PEKK 基质的纤维氧化和热解导致广泛的分层）。第二层对应背面侧，特点是两层，损伤很小。当承受张力时，“未损坏”层的特点是 0° 纤维断裂。这种破坏机制表明，与正交各向异性试样相反，这些“未损坏”的层能够承受很大一部分的拉伸载荷，在正交各向异性试样中，在整个厚度上普遍存在广泛的分层。