散斑尺寸对数字图像相关方法检测表面裂纹的影响  

Effect of speckle size on surface crack detection via digital image correlation

作　　者：Milad Z.Aghdam Nasser Soltani Milad Z.Aghdam;Nasser Soltani(Intelligence Based Experimental Mechanics Center,School of Mechanical Engineering,College of Engineering,University of Tehran,Tehran 1417614411,Iran)

机构地区：[1]德黑兰大学工程学部机械工程学院智能实验力学中心,德黑兰1417614411,伊朗

出　　处：《中国科学技术大学学报》2022年第6期57-66,I0003,共11页JUSTC

基　　金：supported by Intelligence Based Experimental Mechanics (IBEM) center,University of Tehran。

摘　　要：数字图像相关(DIC)是一种用于无损检测的实验应力分析技术。DIC在裂纹检测中的准确性取决于多种因素,如散斑和像素的大小。本文将基于纳米粒子扩散形成的小尺寸散斑的散斑图案与传统的喷涂图案进行比较,以研究是否可以通过减小散斑和像素的大小来改进DIC裂纹检测。由于纳米颗粒尺寸较小,使用光学显微镜对其进行放大。首先,实验研究了扩散法裂纹检测。结果表明,当裂纹边缘具有250 nm开口时,可以很容易地检测到裂纹。随后,将扩散法与使用喷涂法制备图案的传统DIC在裂纹检测方面进行了比较。结果表明,通过减小散斑尺寸和仔细分析散斑图案,此DIC技术在检测小裂纹方面明显优于传统技术。此外,传统技术更适合检测大裂纹。Digital image correlation(DIC) is an experimental stress analysis technique used in nondestructive tests. The accuracy of DIC in crack detection depends on various factors such as the sizes of speckles and pixels. In the current study,a speckle pattern based on the spreading of nanoparticles with small speckles is compared with a conventional sprayed pattern to understand whether crack detection via DIC is improved by reducing the sizes of speckles and pixels. Owing to the small size of nanoparticles, an optical microscope is used for magnification. The spreading method for crack detection is first investigated experimentally. Results show that cracks can be detected easily when a 250 nm opening appears in the crack edges. Subsequently, the spreading method is compared with the conventional DIC, in which the spraying method is used for patterning, in terms of crack detection. Results show that by reducing the speckle size and closely analyzing the speckle pattern, the DIC technique is considerably better than the conventional technique in detecting small cracks.Moreover, the conventional method is more suitable for detecting large cracks.

关 键 词：无损检测 裂纹检测 数字图像相关 

分 类 号：TB121[理学—工程力学]