Development of new repair technologies for out-of autoclave aircraft composite components

今天，民用飞机的主要结构中有相当一部分是由复合材料制成的。这种类型的结构大多是通过高压灭菌法制造的。然而，提高生产率和降低制造成本的需要导致了不需要高压灭菌器的新制造技术的发展。新的外压(OOA)预浸料的配方允许在大气压下仅使用真空袋(VBO)进行零件制造。商用飞机设计和制造的这些变化需要新的设计和分析工具、新的检查和维护方法以及新的维修方法。负责损失评估和修复设计的工程师目前没有足够可靠的分析方法或实用工具来设计高置信度的修复。 为了设计可靠的维修，必须开发强大的分析工具和协议，使工程师能够分析和预测维修组件的行为。这是拟议研究的主要目的。更具体地说，将进行工作，以调查工艺参数对粘结修复的强度和耐久性的影响。还将研究不同维修配置的效果。此外，还将研究环境条件(温度、湿度)对粘结修复的强度和耐久性的影响。将开发工艺和力学模型，并用于夹层和加筋复合材料结构的修复设计。这项研究的结果将为飞机主要部件开发新的维修方法和协议。

Today a significant amount of primary structures of civil aircrafts are made of composite materials. This type of structures is mostly manufactured by autoclave processing. However, the need to increase production rate and to lower manufacturing cost have led to the development of new manufacturing techniques that do not require an autoclave. New out-of-autoclave (OOA) prepregs have been formulated to allow part manufacturing using vacuum-bag-only (VBO) under atmospheric pressure. These changes in the design and manufacture of commercial aircraft require new design and analysis tools, new methods of inspection and maintenance, and new repair methodology. Engineers responsible for damage assessment and repair designs currently do not have sufficient reliable analysis methodology or practical tools to design high confidence repairs. In order to design reliable repairs, it is essential to develop robust analytical tools and protocols to allow engineers to analyze and predict the behavior of the repaired component. This is the main objective of the proposed research. More specifically, work will be conducted to investigate the effect of processing parameters on the strength and durability of bonded repair. The effects of different repair configuration will also be studied. In addition, the effects of environmental conditions (temperature, humidity) on the strength and durability of bonded repair will be investigated. Process and mechanical models will be developed and used for the design of repair applied to sandwich and stiffened composite structures. The results of this research will allow developing new repair methodologies and protocols for primary aircraft components.