Bondline Integrity Monitoring of Adhesively Bonded Joints in Aircraft Structures

粘接层完整性监测是目前飞机结构设计中最重要的问题之一。尽管纤维粘合接头已经显示出优于机械紧固接头的上级性能，但由于在制造和使用期间对粘合层完整性缺乏信心，因此即使具有粘合接头，当前标准仍然需要紧固件。该奖项支持基础研究，为研究一种新的方法提供必要的知识，用于监测胶接接头的胶层完整性。如果成功的话，该项目将大大有利于航空航天和机械结构的设计，因为它增加了使用粘接接头的信心，从而与螺栓接头相比，大大减轻了重量，降低了组装成本，提高了燃油效率，并改善了飞机性能。因此，这项技术将提高美国在所有行业的新型结构系统方面的经济竞争力。这项研究涉及多个学科，包括传感器技术，制造，计算模型和信号处理。因此，这种多学科方法将有助于扩大代表性不足的群体对研究的参与，并将促进学术界和工业界之间的伙伴关系。该项目的目标是开发一种创新的“智能”粘合剂，用于飞机结构中胶接接头的完整性监测和自诊断。该实施将基于可拉伸微/纳米传感器网络的开发，该网络可以嵌入粘合剂层内部，并且能够监测粘合剂胶层界面的完整性并诊断其完整性状态。在整个研究过程中，特别强调的是早期检测和监测弱（“接吻”）债券，到目前为止，还没有成熟的解决方案，提出了无损评估和结构健康监测社区。这项工作包括：（i）开发新型的纳米/微有源传感器和致动器，其可以集成到粘合剂膜中而不引起粘合剂降解，（ii）表征传感器阵列对智能粘合剂的完整性的存在，以及（iii）开发适当的诊断信号处理技术以检测粘合层降解，特别是识别弱粘合的存在。诊断算法以及分析模型的开发将导致嵌入式微传感器和粘接结构之间的复杂的相互作用的全面理解和一个完整的结构健康监测系统的粘接层监测的粘接粘接结构的假设。

Bondline integrity monitoring is one of the most critical concerns in the design of aircraft structures up to date. Although adhesively bonded joints have demonstrated superior properties over mechanically fastened joints, current standards still require fasteners even with bonded joints because of the lack of confidence on the bondline integrity both during fabrication and service. This award supports fundamental research to provide needed knowledge for the investigation of a novel approach for bondline integrity monitoring of adhesively bonded joints. If successful, this project will lead to greatly benefit the design of aerospace and mechanical structures by providing increased confidence on the use of bonded joints leading to a significant weight reductions when compared to bolted joints, reduced assembly cost, increased fuel efficiency, and improved aircraft performance. Therefore, this technology will enhance the economic competitiveness of the US on the novel structural systems front across all industries. This research involves several disciplines including sensor technologies, manufacturing, computational models, and signal processing. Therefore, this multi-disciplinary approach will help broaden participation of underrepresented groups in research and will promote partnerships between academia and industry. The objective of this project is to develop an innovative "intelligent" adhesive for the integrity monitoring and self-diagnosis of adhesively bonded joints in aircraft structures. The implementation will be based on the development of a stretchable micro/nano-sensor network that can be embedded inside the adhesive layer and is capable of monitoring the integrity of the adhesive bondline interfaces and diagnose their integrity status. Throughout this research special emphasis will be given to the early detection and monitoring of weak ("kissing") bonds, for which no mature solutions have been so far proposed by the nondestructive evaluation and structural health monitoring communities. The work involves: (i) development of new types of nano/micro active sensors and actuators that can be integrated into adhesive films without causing adhesive degradation, (ii) characterization of the presence of sensor arrays on the integrity of the intelligent adhesive, and (iii) development of appropriate diagnostic signal processing techniques to detect bondline degradation, and particularly to identify the existence of weak bonds. The diagnostic algorithms as well as the analytical models to be developed will lead to the comprehensive understanding of complex interaction between embedded micro-sensors and the bonded structure and the postulation of a complete structural health monitoring system for bondline monitoring of adhesively bonded structures.