Hot/wet properties of high temperature composites

高温复合材料的热/湿性能

• 批准号: 2738897
• 金额: --
• 依托单位: University of Bristol
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2738897
• 关键词: Hot; wet; properties; temperature; composites

The replacement of metals with advanced composite materials within a range of industries has become commonplace. This is due to their excellent specific stiffness and strength, wide range of available constituents and array of manufacturing processes, making them suitable for a multitude of applications, including within the aerospace and energy sectors. As composites are employed in more extreme environments, there has been considerable interest in organic matrices that are able to withstand high temperatures and humidities. Thus, research has been conducted to develop novel thermoset systems with enhanced thermal and moisture durability properties. There has been specific interest in cyanate esters due to their desirable viscosity properties for resin infusion and high glass transition temperatures, making them suitable for a range of applications. Although there is some understanding of the behaviour of the neat resin, there is little knowledge on its performance when integrated within composite laminates. Delamination, the separation of layers, is the primary failure mechanism within composites. Fracture toughness is a measure of a material's resistance to delamination. Most tentative applications for these novel materials involve cycling components in the presence of heat and moisture which accelerates degradation mechanisms. Therefore, it is imperative to understand the interlaminar fracture toughness properties of these thermoset systems, with a particular focus on how they react in hot-wet conditions, before they can become routinely used within composites. This project will focus on the experimental testing of a leading aerospace-grade epoxy-based composite material, IM7-8552, in conjunction with composites containing the novel thermoset resins. This will allow a baseline set of properties to be acquired for performance comparison with the newly developed materials. Although regulations for moisture conditioning of test specimens exist, there is no universally accepted testing standard for acquiring fracture properties of composites at elevated temperatures and humidities. For this reason, a key objective of this project is to develop a more robust, reliable method for testing within extreme environments, along with obtaining the fracture properties themselves. Testing will initially be conducted in static and quasi-static conditions, followed by fatigue testing performed to mimic the conditions experienced by materials in-service under continuous cycling and vibration exposure whilst in high temperature environments. Fractographic analyses will be conducted to create qualitative measures of fractured surfaces, developing easily identifiable visual indicators of how the material failed in each set of testing conditions for future comparison. Once the behaviour of the novel thermoset systems within composites is more thoroughly understood, supported through rigorous testing within this project, the envisaged application for their use is within the turbofan engines developed by Rolls Royce. However, if these materials prove to have enhanced durability within environments involving repeated cycling at elevated temperatures, this will open them up for use within a broad spectrum of applications. These could include conventional gas turbines, advanced hybrid electric propulsion systems, motors, generators, and hydrogen storage tanks. The development of a vigorous protocol for static, quasi-static and fatigue testing in elevated temperatures and humidities will be a significant contribution to the fracture mechanics research field. The ability to confidently produce a data set of properties tested within these conditions is essential for the progression of high temperature composites as the boundaries for their use continue to be broadened.

在一系列行业中，用先进的复合材料代替金属已经变得司空见惯。这是由于其优异的比刚度和强度，广泛的可用成分和制造工艺，使其适用于多种应用，包括航空航天和能源领域。随着复合材料在更极端的环境中的应用，人们对能够承受高温和高湿度的有机基质产生了相当大的兴趣。因此，已经进行了研究以开发具有增强的耐热性和耐湿性的新型热固性体系。氰酸酯由于其理想的树脂灌注粘度特性和高玻璃化转变温度而受到特别关注，使其适用于一系列应用。尽管对纯树脂的行为有一些了解，但对其在复合材料层压板中集成时的性能知之甚少。分层，层的分离，是复合材料中的主要失效机制。断裂韧性是材料抗分层的量度。这些新材料的大多数试验性应用涉及在热和水分存在下循环组件，这加速了降解机制。因此，必须了解这些热固性系统的层间断裂韧性特性，特别关注它们在热湿条件下如何反应，然后才能在复合材料中常规使用。该项目将重点对领先的航空级环氧基复合材料IM 7 -8552进行实验测试，并将其与含有新型热固性树脂的复合材料结合起来。这将允许获得一组基线属性，用于与新开发的材料进行性能比较。虽然存在测试样品的湿度调节的规定，但没有普遍接受的测试标准来获得复合材料在高温和高湿度下的断裂性能。出于这个原因，本项目的一个关键目标是开发一种更强大，更可靠的方法，用于在极端环境中进行测试，沿着获得断裂特性。试验最初将在静态和准静态条件下进行，然后进行疲劳试验，以模拟高温环境下连续循环和振动暴露下使用中的材料所经历的条件。将进行断口分析，以创建断裂表面的定性测量，开发易于识别的视觉指标，说明材料在每组测试条件下如何失效，以供将来比较。一旦对复合材料中新型热固性系统的行为有了更透彻的了解，并通过该项目中的严格测试得到支持，那么它们的设想应用将在罗尔斯·罗伊斯开发的涡轮风扇发动机中使用。然而，如果这些材料被证明在涉及高温下重复循环的环境中具有增强的耐久性，这将使它们在广泛的应用中使用。这些可能包括传统的燃气轮机，先进的混合动力电力推进系统，电动机，发电机和储氢罐。高温高湿条件下的静态、准静态和疲劳试验方案的发展将对断裂力学研究领域做出重大贡献。随着高温复合材料使用范围的不断扩大，在这些条件下自信地生成测试性能数据集的能力对于高温复合材料的发展至关重要。