MRI: Acquisition of Digital Image Correlation System for Real-Time 3D Measurements and Closed-Loop Control

这一重大研究仪器(MRI)项目涉及获取数字图像相关系统。摄影测量技术实时提供复杂测试系统的三维位移的全场非接触测量。其目的有两个方面，(A)在不使用应变计和差动传感器等传统接触测量的情况下，检测和可视化试件上出现的裂纹和应变集中，以及(B)开发自适应反馈信号，以控制故障前和故障后的力输入。Trilion Inc.的3D DIC测量系统包括四对1200万像素的数码相机、Tritop坐标测量系统、图像处理工作站和控制器，以及带有实时控制接口的Aramis处理软件。每一对数码相机都安装在带有专用照明的三脚架上，以提供视场内测试物品的一系列立体图像。Aramis处理软件跟踪10,000多个小平面的坐标。该便携式仪器系统将为本科生和研究生提供新的机会，让他们熟悉数字图像相关系统的能力及其在从测试材料和基础设施部件到生物医学应用的各种研究项目中的应用。在11名教师的指导下，土木工程和机械工程专业的学生将接受以下方面的培训：(A)使用强大的成像来跟踪新出现的故障机制，以及(B)材料和结构的伺服控制测试领域。

This Major Research Instrumentation (MRI) project involves acquisition of a Digital Image Correlation System. The photogrammetric technology provides full-field non-contact measurements of 3D displacements of complex test systems in real-time. The intent is two-fold, (a) to detect and visualize emerging cracks and strain concentrations on test articles without the use of traditional contact measurements such as strain gauges and differential transducers, and (b) to develop an adaptive feed-back signal for controlling the force input in the pre- and post-failure regime. The 3-D DIC measurement system by Trilion Inc. includes four pairs of 12 megapixel digital cameras, the Tritop coordinate measurement system, an image processing workstation and controller, and the Aramis processing software with a real-time interface for control. Each pair of digital cameras is mounted on a tripod with dedicated lighting to provide a series of stereoscopic images of the test article within the field of view. The Aramis processing software tracks the coordinates of 10,000+ facet points. It provides deformation field data for structural materials testing up to and beyond their maximum load resistance, and progressive failure such as crack initiation and propagation in structural components and systems.The portable instrumentation system will provide new opportunities for undergraduate and graduate students to acquaint themselves with the capabilities of digital image correlation systems and their application to a variety of research projects spanning from testing materials and infrastructural components to biomedical applications. Under the direction of eleven faculty, students in Civil and Mechanical Engineering will be trained in (a) the use of powerful imaging to track emerging failure mechanisms, and (b) the field of servo-controlled testing of materials and structures.