Characterization of guided wave propagation in aircraft structures

结构健康监测（SHM）是航空航天界感兴趣的一个主要领域，特别是考虑到老化的飞机，全球每年的维护成本估计为10,4亿美元。该行业的5至10年目标是部署SHM系统，该系统将1）满足在役检测要求，传感器永久安装在结构上，2）与基线检测方法相比，提供经济效益。已经提出了使用导波传播的策略用于机身结构的嵌入式监测。然而，波的传播和相互作用与复杂结构中的缺陷，在文献中只针对特定的和有限数量的组件和类型的缺陷。例如，在一定程度上研究了与金属接头中的裂纹和复合材料接头中的脱粘的相互作用。这种基于知识缺口的研究的目的是为行业提供各种基本飞机结构或标准的扩展知识库，从中可以推断出导波传播和与其他特定结构缺陷的相互作用。知识库将包含参数，例如在结构中传播或与缺陷相互作用的模式的类型、波的衰减、波的空间模式和色散曲线。该项目的具体目标是：1）开发一个标准的过程来表征导波传播，2）开发一个知识库的导波特性的各种常见的飞机结构，3）开发一个知识库的导波相互作用机制与损伤的各种常见的飞机结构和4）提出SHM设计准则的导波在飞机结构。这样的知识库将使工业合作伙伴能够优化传感配置，并通过减少所需的测试来最大限度地减少开发时间，以验证和鉴定SHM应用程序的损坏监测。

Structural health monitoring (SHM) is a major area of interest for the aerospace community, especially considering aging aircraft where the growing maintenance costs estimated to $10,4 billion worldwide annually. The 5 to 10 years goal of the industry is to deploy SHM systems which will 1) meet the in-service inspection requirements with sensors permanently installed on the structure and 2) provide economic benefits compared to the baseline inspection methods. Strategies using guided wave propagation have been proposed for embedded monitoring of airframe structures. However, wave propagation and interaction with defects in complex structures is addressed in the literature only for specific and limited number of components and types of defects. For example, interaction with cracks in metallic joints and debonding in composite joints has been investigated to some extent. The objective of this knowledge-gap based research is to provide the industry with an extended knowledge base for a variety of basic aircraft structures, or standards, from which the guided wave propagation and interaction with defects for other specific structures could be inferred from. The knowledge base will contain parameters such as the type of modes propagating in the structures or interacting with defects, the attenuation of the waves, the spatial pattern of the waves and the dispersion curves. The specific objectives of the project are: 1) develop a standard process to characterize guided wave propagation, 2) develop a knowledge base of guided wave characteristics for a variety of common aircraft structures, 3) develop a knowledge base of guided wave interaction mechanisms with damage for a variety of common aircraft structures and 4) propose SHM design criteria for guided waves in aircraft structures. Such a knowledge base would allow industrial partners to optimize sensing configuration and minimize development time, by reducing required testing for validation and qualification of SHM applications for damage monitoring.