Novel Integrated Imaging Approaches for Damage Characterisation of Composite Materials and Structures

纤维增强聚合物(FRP)复合材料广泛应用于航空、海洋、交通和能源结构等领域。相对于它们的重量，它们表现出较高的硬度和强度，并且在承受疲劳负荷时表现出优异的性能。一个重大缺陷是了解材料中的损坏是如何演变的，以及评估部件是否应该修复或继续使用的能力。其结果是保守的设计和制造阶段不必要的报废。人们努力使用各种无损评估(NDE)技术来更好地评估复合材料结构。然而，业界渴望的“一站式”检查仍然难以实现。在航空航天和风力涡轮机领域，目前工业首选的技术是超声波，而在航运领域，通常使用简单的敲击测试。目前的技术(如超声波(UT))的局限性在于，它们不能提供关于损伤或缺陷如何演变并影响部件使用寿命的细节。该博士项目旨在开发一种被称为“基于菌株的无损检测”的想法。在这里，全场成像技术被用来捕捉与损伤引起的应变直接相关的数据，以提供关于损伤影响的预测信息。该系统将使人们能够对报废/修理/继续使用作出决定。一个重点是通过用低成本的测辐射热计取代昂贵的红外探测器来降低这种系统的成本。一个主要的挑战是白光和红外成像收集的图像的整合。众所周知，当复合材料被构造成复杂形状的大型结构并承受多轴载荷时，它们的性能是不同的。基于应变的无损检测技术已经在简单的构件上进行了演示，因此本项目的目的是检测复杂几何形状的实际结构构件，并原位表征材料的损伤状态。

Fibre reinforced polymer (FRP) composite materials are widely used for aero, marine, transportation and energy structure applications. They exhibit high stiffness and strength relative to their weight, and excellent performance when subjected to fatigue loads. A significant drawback is understanding how damage evolves in the materials and the ability to assess if a component should be repaired or continue in service. The outcome is conservative design and unnecessary scrap at the manufacturing stage. Efforts have been made to better assess composite structures using a variety of non-destructive evaluation (NDE) techniques. However the industrially desired 'one stop shop' for inspection has remained elusive. The current industrially preferred technique in the aerospace and wind turbine sectors is ultrasound, and in the shipping sector simple tap tests are often used. The limitation of current techniques (such as ultrasound (UT)) is they cannot provide details on how damage or defects evolve and affect the service life of a component. The PhD project aims at developing an idea known as 'Strain-based NDE'. Here full field imaging techniques are used to capture data that is directly related to the strain caused by the damage to provide prognostic information on the effect of damage. The system will enable decisions to be made on scrap/repair/continue in service. A focus is reducing the cost of such a system by replacing expensive IR detectors with low cost bolometers. A major challenge is the integration of the images collected by white light and infrared imaging. It is well known that composite materials behave differently when they are constructed into a large structure of complex shape and subjected to multi-axial loading. The strain based NDE technique has been demonstrated on simple components so the purpose of this project is to examine actual structural components of complex geometry and characterise the material damage state in-situ.