García-Moreno Irene, Caminero Miguel Ángel, Rodríguez Gloria Patricia, López-Cela Juan José
Escuela Técnica Superior de Ingenieros Industriales, INEI, Universidad de Castilla-La Mancha, Campus Universitario s/n, 13071-Ciudad Real, Spain.
Polymers (Basel). 2019 Jan 17;11(1):160. doi: 10.3390/polym11010160.
Composite structures are particularly vulnerable to impact, which drastically reduces their residual strength, in particular, at high temperatures. The glass-transition temperature () of a polymer is a critical factor that can modify the mechanical properties of the material, affecting its density, hardness and rigidity. In this work, the influence of thermal ageing on the low-velocity impact resistance and tolerance of composites is investigated by means of compression after impact (CAI) tests. Carbon-fibre-reinforced polymer (CFRP) laminates with a of 195 °C were manufactured and subjected to thermal ageing treatments at 190 and 210 °C for 10 and 20 days. Drop-weight impact tests were carried out to determine the impact response of the different composite laminates. Compression after impact tests were performed in a non-standard CAI device in order to obtain the compression residual strength. Ultrasonic C-scanning of impacted samples were examined to assess the failure mechanisms of the different configurations as a function of temperature. It was observed that damage tolerance decreases as temperature increases. Nevertheless, a post-curing process was found at temperatures below the that enhances the adhesion between matrix and fibres and improves the impact resistance. Finally, the results obtained demonstrate that temperature can cause significant changes to the impact behaviour of composites and must be taken to account when designing for structural applications.
复合材料结构特别容易受到冲击影响，这会大幅降低其残余强度，尤其是在高温下。聚合物的玻璃化转变温度（）是一个关键因素，它可以改变材料的机械性能，影响其密度、硬度和刚度。在这项工作中，通过冲击后压缩（CAI）试验研究了热老化对复合材料低速抗冲击性和耐受性的影响。制造了玻璃化转变温度为195°C的碳纤维增强聚合物（CFRP）层压板，并在190°C和210°C下进行了10天和20天的热老化处理。进行了落锤冲击试验，以确定不同复合层压板的冲击响应。在非标准CAI装置中进行冲击后压缩试验，以获得压缩残余强度。对冲击后的样品进行超声波C扫描，以评估不同结构随温度变化的失效机制。观察到，随着温度升高，损伤容限降低。然而，在低于玻璃化转变温度的温度下发现了一种后固化过程，该过程增强了基体与纤维之间的粘附力并提高了抗冲击性。最后，获得的结果表明，温度会导致复合材料的冲击行为发生显著变化，在设计结构应用时必须予以考虑。
