CAREER: Multi-Physics Transient Holography: A Non-Intrusive Imaging Approach for the Identification of Structural Damage in Mechanical Systems

该学院早期职业发展（Career）项目旨在推进结构健康监测的非破坏性/非侵入性成像技术的发展。结构健康监测是一个高度多学科的工程领域，研究先进的传感系统和数据分析方法来评估结构的完整性。这些监控系统有可能彻底改变运输系统和基础设施的维护策略，允许频繁或连续的检查，从而最终提高安全性和可靠性，降低运营成本。具体来说，实现向基于状态的维护战略的过渡是确保我国基础设施长期可持续性的关键。该研究探索了一种新的成像技术概念，该技术利用并结合了多种物理原理，从机械到热到电磁场，产生了一种高灵敏度的方法，能够实现超越当前成像技术的性能。该项目将研究这种先进成像技术的基本原理，并将通过实验室测试证明其有效性。这项研究的结果将有利于当前和未来的美国基础设施和运输系统，并将为该技术向其他领域的过渡奠定基础，例如医学成像和材料表征，在这些领域，高度敏感和准确的成像工具是使能技术。所研究的方法是基于多物理场瞬态全息的新思想，利用电磁-热-声耦合响应来探测结构和检测损伤。层析成像问题是利用穿透波重建物体内部特征的图像，为了达到前所未有的图像分辨率和检测性能，将其置于全息框架中。与目前的技术相比，多物理场方法将提供更高的损伤灵敏度，同时允许大大减少传感网络。为了释放全息方法的全部潜力，本研究还将探索与图像重建互补的新技术，如数据处理、数学建模和换能器开发。与层析成像的一般领域特别相关的是基于自适应网格的新一代多分辨率计算模型的制定，以及用于多模式驱动和传感的柔性皮肤传感器的新概念。专用软件和硬件也将通过实验室实验支持成像技术的验证和性能表征。

This Faculty Early Career Development (CAREER) Program project aims at advancing the state-of-the-art in non-destructive/non-intrusive imaging techniques for structural health monitoring. Structural health monitoring is a highly multidisciplinary area of engineering that investigates advanced sensing systems and data analysis methodologies to assess the integrity of structures. These monitoring systems have the potential to revolutionize the maintenance strategy for transportation systems and infrastructure by allowing frequent or continuous inspections thus ultimately increasing safety and reliability at reduced operating costs. Specifically, enabling the transition to a condition-based maintenance strategy is key to ensure the long-term sustainability of our nation infrastructures. The research explores a new concept of imaging technology that leverages and combines multiple physical principles, ranging from the mechanical to the thermal to the electromagnetic fields, yielding a highly sensitive approach able to achieve performance beyond current imaging techniques. The project will investigate the fundamental principles of this advanced imaging technology and will demonstrate its effectiveness through laboratory tests. The outcome of this research will benefit the current and future US infrastructure and transportation systems and will lay the foundations for the transition of this technology to other fields, such as medical imaging and material characterization, where highly sensitive and accurate imaging tools are enabling technologies. The approach to be investigated is based on the novel idea of multi-physics transient holography, whereby the coupled electromagnetic-thermo-acoustic response is exploited to probe the structure and detect damage. The tomographic problem, which consists in reconstructing images of the interior properties of an object by using penetrating waves, is cast in a holographic framework in order to achieve unprecedented image resolution and detection performance. The multi-physics approach will provide increased damage sensitivity while allowing a largely reduced sensing network, compared to current technologies. In order to unlock the full potential of the holographic approach, this research will also explore new technologies in areas that are complementary to image reconstruction such as data processing, mathematical modeling, and transducers development. Of particular relevance for the general field of tomographic imaging is the formulation of a new generation of multi-resolution computational models based on adaptive grids and of a novel concept of flexible skin transducer for multi-mode actuation and sensing. Dedicated software and hardware will also support the validation and performance characterization of the imaging technique via laboratory experiments.