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

金属添加剂-使用激光烧结直接从3D计算机模型逐层制造零件的制造技术已经出现，并在过去十年中迅速发展。这种技术可以显著缩短上市时间，提高产品质量，减少材料浪费，降低成本。该项目将帮助克服目前在这项技术被广泛采用之前存在的重要障碍。这项研究将在制造过程中使用基于涡流的新型传感机制，从而在降低成本的同时实现制造精度。这项技术将允许在零件制造过程中进行可靠的逐层质量评估，并将加快生产率，消除制造后检查或破坏性测试。虽然该方法是在金属添加剂制造的背景下进行的，但潜在的系统架构和思想可以扩展以产生一系列不同的应用；例如，用于准确诊断脑出血的磁感应断层扫描等新的医疗应用。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行业。除了课程开发外，该项目还包括有趣的K-12外展工作。这项研究的目的是开发一种新的方法来对分布参数系统进行建模，重建其物理场，并从有限的测量中推断其系统特性，以分析和控制其动态行为。提出了一种基于多频涡流传感的新型多目标传感方法，用于重建加工过程中测量几何参数以及检测表面和亚表面缺陷的物理场。该工作还将建立薄壁板加工过程的动力学模型，并开发有效的方法来根据有限的位移测量实时重建其位移、应变场和应力场，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相邻线圈之间相对较高分辨率的涡流图案，并结合适当的频率来同时确定位移、厚度和电导率。用于传感器设计和分析的分布式电流源(DCS)建模方法效率高，降低了计算复杂度。在零件制造过程中，从多目标传感器和场重建算法中重建多物理场(电场、磁场、位移、力、应变和应力)的能力，不仅可以直观地了解几个关键因素(如材料机械性能、边界几何/夹紧约束和阻尼系数)对热/机械加工引起的残余应力的影响，这些残余应力通常是导致薄壁产品变形的主要原因，而且还将为振动抑制提供必要的基础。

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.