Advanced Tomographic Techniques for Volumetrically Inspecting Wide Aspect Ratio Composites

复合材料越来越多地用于主要结构项目，其中组件厚度可以非常大-大于100 mm-并且具有非常大的纵横比（例如用于航空航天和风力涡轮机应用）。复合材料的衰减性质可能使超声波技术无法使用。X射线计算机断层扫描（CT）提供了解决方案，但传统的方法确实受到许多限制：它们需要测试对象或射线照相设备的完整360 °旋转，以便获得体积图像重建所需的完整数据集，这并不总是可能的。大的纵横比也会在重建数据中产生射束硬化或其他伪影，使内部特征模糊不清。本项目旨在研究使用多个X射线能量曝光进行CT数据采集和重建，以增加宽纵横比组件的容差。还将开展研究，将多能量技术应用于先进的断层摄影方法，如分层摄影和断层合成，这可以克服单色X射线吸收模型重建产生的伪影的一些物理限制。

Composites are increasingly used for major structural items where component thicknesses can be very large - greater than 100mm - and have very large aspect ratios (eg for aerospace and wind turbine applications). The attenuative nature of composites can render ultrasonic techniques unusable. X-ray computed tomography (CT) offers solutions, but traditional methodologies do suffer a number of limitations: they require a full 360o rotation of either the object under test or the radiographic equipment in order to obtain a complete dataset necessary for volumetric image reconstruction, which is not always possible. The large aspect ratios also produce beam hardening or other artefacts in the reconstructed data, obscuring internal features.This project aims to investigate the use of multiple X-ray energy exposures for CT data capture and reconstruction in order to increase the tolerance of wide aspect ratio components. Research will also be carried out to apply multi-energy techniques to advanced tomographic methodologies such as laminography and tomosynthesis, which can overcome some of the physical limitations in artefacts arising from monochromatic X-ray absorption model reconstruction.