Simultaneous Physical Field Reconstruction and Property Identification Using Multi-Target Sensing Methods for Metal Additive-Manufacturing and Thin-Walled Machining

金属增材制造使用激光烧结直接从3D计算机模型逐层制造零件已经出现，并在过去十年中迅速发展。这种技术可以大大缩短产品上市时间，提高产品质量，减少材料浪费，降低成本。该项目将有助于克服目前在广泛采用这项技术之前存在的重要障碍。本研究将在制造过程中使用基于涡电流的新型传感机制，这将使制造精度沿着降低成本。这种技术将允许在制造部件时进行可靠的逐层质量评估，并且生产率将加快，消除了构建后检查或破坏性测试。虽然该方法是在金属增材制造的背景下，但底层系统架构和想法可以扩展到产生一系列不同的应用;例如，新的医疗应用，如用于准确诊断脑出血的磁感应断层扫描。几个行业可能会受益，包括汽车，航空航天，医疗保健和工业制造业。除了课程开发外，该项目还包括有趣的K-12外联工作。 研究的目的是开发一种新的方法来建模的分布参数系统，重建其物理场，并推断其系统属性从有限的测量分析和控制其动态行为。 一种新的多目标传感方法的基础上，一组多频涡流传感将开发用于重建的物理场测量几何参数，以及检测表面和亚表面缺陷在加工过程中。本文还将建立薄壁板在加工过程中的动力学模型，并开发出有效的方法，用于从真实的有限位移测量中重建其位移、应变和应力场，以监测和控制分布参数系统的动力学。 与传统的单频涡流传感器不同，多目标传感系统可以自适应地合成具有适当频率的组合的相邻线圈之间的相对高分辨率的涡流图案，以同时确定位移、厚度和电导率。 分布式电流源（DCS）建模方法用于传感器的设计和分析是高效的，并降低了计算复杂度。 人们期望，重建多物理场的能力在零件制造过程中，多目标传感器和场重建算法的电磁场（电、磁、位移、力、应变和应力）不仅可以直观地了解几个关键因素的影响，（例如材料机械性能，边界几何/夹紧约束和阻尼系数）对热/加工引起的残余应力的影响，也将为振动抑制提供必要的依据。

Metallic Additive-Manufacturing using laser sintering to fabricate parts layer-by-layer directly from a 3D computer model has emerged and has grown rapidly in the past decade. Such technology can significantly reduce time-to-market, improve product quality, reduce material-waste, and reduce cost. This project will help overcome important roadblocks that currently exist before this technology can be widely adopted. This research will use eddy current-based novel sensing mechanism during manufacturing process that will enable precision in manufacturing along with reduced cost. This technique will allow a robust layer-by-layer quality assessment while the part is being fabricated and the production rates will be expedited eliminating post-build inspection or destructive testing. While the method is in the context of metal additive manufacturing, the underlying system architecture and ideas can be extended to spawn a spectrum of different applications; for example, new medical applications such as magnetic induction tomography for accurate diagnosis of intracerebral hemorrhage. Several industries may benefit, including the automotive, the aerospace, the medical and healthcare, and industrial manufacturing sectors. The project also includes interesting K-12 outreach efforts in addition to curriculum development. The objective of the research is to develop a novel methodology to model a distributed-parameter system, reconstruct its physical fields and infer its system properties from limited measurements for analyzing and controlling its dynamic behaviors. A novel multi-target sensing methodology based on a set of multi-frequency eddy-current sensing will be developed for reconstructing the physical fields which measure geometrical parameters as well as detect surface and subsurface defects during the machining process. The work will also formulate dynamic model of the thin-walled plate during machining, and develop efficient methods for reconstructing its displacement, strain and stress fields from limited displacement measurements in real time for monitoring and controlling the dynamics of the distributed-parameter system. Unlike traditional single-frequency eddy-current sensors the multi-target sensing system can adaptively synthesizes a relatively high-resolution eddy-current pattern between adjacent coils with a combination of appropriate frequencies to simultaneously determine the displacement, thickness and electrical conductivity. The distributed current source (DCS) modeling method for sensor design and analysis is highly efficient and reduces computational complexity. It is expected that the ability to reconstruct the multi-physical fields (electric, magnetic, displacement, force, strain and stress) from the multi-target sensors and field reconstruction algorithms during part fabrication not only will offer intuitive insights into the effects of several critical factors (such as material mechanical properties, boundary geometrical/clamping constraints and damping coefficients) on thermal/machining induced residue stresses that are generally the main cause of thin-walled product distortions, and but also will provide an essential basis to vibration suppression.