A 360-deg Digital Image Correlation system for materials testing
A 360-deg Digital Image Correlation system for materials testing
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DOI：
10.1016/j.optlaseng.2016.02.015
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发表时间：
2016-07-01
影响因子：
4.6
通讯作者：
Amodio, D.
中科院分区：
文献类型：
--
作者：
Genovese, K.;Cortese, L.;Amodio, D.
对天然和先进工程材料的研究兴趣日益增加，需要新的实验方案，能够在多种加载条件下检索样品全表面上的高密度实验数据集。事实上，这些信息将允许通过使用最新的逆表征方法来捕获材料的可能的异质性和各向异性。尽管特定对象测试协议的开发可能是满足这一需求的最佳选择，但毫无疑问，通用试验机（UTM）仍然是学术和工业环境中测试材料和组件的最广泛和最通用的选择。然而，使用UTM进行标准材料测试的主要限制在于，由于通常相关的传感器仅提供全局信息，因此可获得的信息很少。（LVDT、引伸计、2D视频分析仪）或本地本文介绍了一种三维数字图像相关（DIC）系统，该系统被开发用于执行高精度的全表面360度测量。在通用试验机内复杂载荷下对标准或定制形状样品进行度测量。为此，专门设计了一种低成本且易于设置的视频装备，以克服在现有装载框架内集成多摄像机系统所带来的实际限制。特别是，建议的系统具有一个单一的单反数码相机移动通过多个位置周围的标本通过一个大的旋转阶段。一个适当的校准和数据处理程序允许自动合并从多个视图获得的实验数据，精度为10（-2）mm。在这里报告和讨论的结果的一个完整的基准测试系统的抗拉性能的完整的360度的形状和变形测量等级X65钢样品在拉伸载荷下的说明性例子。该方法被证明是稳健和准确的，因此代表了一个可行的实用解决方案，以提供材料和组件测试领域的现代挑战。(C)2016爱思唯尔有限公司版权所有
The increasing research interest toward natural and advanced engineered materials demands new experimental protocols capable of retrieving highly dense sets of experimental data on the full-surface of samples under multiple loading conditions. Such information, in fact, would allow to capture the possible heterogeneity and anisotropy of the material by using up-to-date inverse characterization methods. Although the development of object-specific test protocols could represent the optimal choice to address this need, it is unquestionable that universal testing machines (UTM) remain the most widespread and versatile option to test materials and components in both academic and industrial contexts. A major limitation of performing standard material tests with UTM, however, consists in the scarce information obtainable with the commonly associated sensors since they provide only global (LVDTs, extensometers, 2D-video analyzers) or local (strain gages) measures of displacement and strain.This paper presents a 3D Digital Image Correlation (DIC) system developed to perform highly accurate full-surface 360-deg measurements on either standard or custom-shaped samples under complex loading within universal testing machines. To this aim, a low cost and easy to setup video rig was specifically designed to overcome the practical limitations entailed with the integration of a multi camera system within an already existing loading frame. In particular, the proposed system features a single SLR digital camera moved through multiple positions around the specimen by means of a large rotation stage. A proper calibration and data-processing procedure allows to automatically merge the experimental data obtained from the multiple views with an accuracy of 10(-2) mm.The results of a full benchmarking of the metrological performances of the system are here reported and discussed together with illustrative examples of full-360-deg shape and deformation measurements on a Grade X65 steel sample under tensile loading. The methodology demonstrated to be robust and accurate thus representing a viable practical solution to afford the modern challenges in the field of materials and components testing. (C) 2016 Elsevier Ltd. All rights reserved.