Non-local modeling and characterization tools for heterogeneous materials

航空航天、汽车、能源和其他几个行业的未来与减少所涉及的结构的能源足迹和质量密切相关，同时保持类似的性能和安全水平。为了实现这些目标，人们越来越多地使用非均质材料，即在其机械性能方面表现出强烈局部差异的材料。我的研究重点是非均质材料的力学，更具体地说，是为其特征量身定做的全场多尺度测量方法的发展。在上个世纪，人们付出了巨大的努力来表征广泛使用的金属材料的微观结构，并了解它们的行为和失效情况。今天，这使工程师能够强有力地预测金属部件的行为，并优化其设计和维护。对于非均质材料，这项工作的大部分仍有待完成。异质性可以通过存在几个不同的相，即复合材料，或通过局部影响材料的机械性能的制造过程，例如3D打印或焊接，在材料中引入。在过去的几十年里，除了引入了导致异质部件的新的制造工艺外，大多数行业都经历了纤维增强复合材料的急剧增加。这些材料的宏观行为是由其局部特征(即空洞、裂纹、界面和中间相)的行为驱动的，这些特征可能导致不连续的位移场。因此，需要能够处理不连续位移场的全场多尺度测量工具来研究它们。该发现计划旨在通过三个目标促进非均质材料力学和非局部建模领域的发展：(I)开发能够捕捉非均质材料局部行为的实验装置；(Ii)非局部非均质材料行为的建模；以及(Iii)通过一组旨在表征非均质材料中不连续性源行为的实验来验证它们。在这项工作中将获得的实验装置、软件和实验结果有望进一步加深我们对非均质力学的理解，更具体地说，我们对局部特征如何影响材料的宏观性质的理解。这项研究的成果有望提高航空航天、汽车和能源行业中非均质材料的有效利用。未来的工作将依靠该计划的输出来开发工程设计方法，类似于技术标准，专门为使用全场多尺度表征工具研究的非均质材料量身定做。

The future of the aerospace, automotive, energy and several other industries is strongly linked to a reduction of the energy footprint and mass of the structures involved while maintaining a similar level of performance and safety. To achieve these objectives, heterogeneous materials, materials that exhibit strong local variations in their mechanical properties, are increasingly being used. My research focuses on the mechanics of heterogeneous materials and more specifically on the development of full field multiscale measurement methods tailored for their characterization. During the last century, colossal efforts have been put in place to characterize the microstructure of widely used metallic materials and understand how they behave and fail. Today, this allows engineers to robustly predict the behavior of a metallic part and to optimize its design and maintenance. For heterogeneous materials, the bulk of this work still remains to be done. Heterogeneity can be introduced within a material through the presence of several dissimilar phases, i.e. composite materials, or through a manufacturing process that locally affects the mechanical properties of a material, e.g. 3D-printing or welding. During the last decades, most industries have undergone a sharp increase in the use of fiber reinforced composites, in addition to the introduction of novel manufacturing processes that lead to heterogeneous parts. The macroscopic behavior of these materials is driven by the behavior of their local features, i.e. voids, cracks, interfaces and interphases, that can lead to a discontinuous displacement field. Full field multiscale measurement tools which can handle discontinuous displacement fields are thus required to study them. This Discovery program aims at contributing to the field of the mechanics of heterogeneous materials and non-local modeling through three objectives: (i) the development of an experimental setup able to capture the local behavior of heterogeneous materials; (ii) the non-local modeling of the local behavior of heterogeneous materials; and (iii) their validation through a set of experiments aimed at characterizing the behavior of sources of discontinuities in heterogeneous materials. The experimental setup, software and experimental results that will be obtained during this work are expected to further our understanding of the mechanics of heterogeneous and more specifically our understanding of how local features affect the macroscopic properties of a material. The output of this research is expected to improve the efficient use of heterogeneous materials in the aerospace, automotive and energy industries. Future works will rely on the output of this program to develop engineering design methods, akin to technical standards, specifically tailored for heterogeneous materials studied using full field multiscale characterization tools.