New Dimensions of Engineering Science at Large Facilities

多组分、空间变化的应力应变状态和结构信息的知识对于阐明材料科学和强度工程中的先进概念和模型至关重要。在大型科学设施中，中子和高能x射线衍射技术的最新发展将空间分辨率推向了更小的长度尺度，同时提高了数据采集率，使获得大量衍射图案成为可能。然而，由于测量体积几何和物体颗粒结构的限制，所需的信息通常以隐式形式包含在这些数据集中，例如卷积或平均值。最近已经证明，类似于层析重建方法的鲁棒反问题公式可以成功地用于解卷积关于材料结构、纹理和变形的详细的、空间分辨的信息。本项目将开发系统的方法来处理多余的高能x射线和中子衍射数据集，以提取随时间变化的、三维的、多分量的应变、纹理和损伤图。x射线衍射实验将在Diamond的JEEP光束线上进行，在ESRF的ID15A光束线上进行，在ISIS的engine - x仪器上获得中子透射数据。研究结果将为未来先进工程材料和部件的应变、纹理和结构的多维分析（3D和时间分辨）方法奠定基础。

The knowledge of multi-component, spatially varying stress and strain states and structural information is crucial for elucidating advanced concepts and models in materials science and strength engineering. Recent developments in neutron and high energy X-ray diffraction techniques at large scientific facilities have pushed the spatial resolution towards ever smaller length scales, at the same time improving data acquisition rates, making it possible to obtain large collections of diffraction patterns. However, because of the limitations imposed by gauge volume geometry and grain structure of the object the desired information is often contained within these data sets in implicit form, e.g. as convolutions or averages. Recently it has been demonstrated that robust inverse problem formulations akin to tomographic reconstruction methods can successfully be used to de-convolve detailed, spatially resolved information about material structure, texture and deformation. The present project will develop systematic approaches to the treatment of redundant high energy X-ray and neutron diffraction data sets for the purpose of extracting time-dependant, three-dimensional, multi-component maps of strain, texture and damage. X-ray diffraction experiments will be conducted on the JEEP beamline at Diamond, beamline ID15A at the ESRF, and neutron transmission data will be obtained on the ENGIN-X instrument at ISIS. The results will establish foundations for future methodologies for multi-dimensional analysis (3D and time-resolved) of strain, texture and structure of advanced engineering materials and components.