摘要
为了解决传统数字图像相关法(DIC)对变形较大的裂纹边缘测量时出现的裂纹底色导致匹配相关性差、测量精度低的问题,提出一种引入高斯加权系数的裂纹边缘变形测量方法。该方法首先根据灰度梯度平方和比较算法自动调节匹配子区的高斯中心点位置;然后,通过恒定位移填充模拟试验确定高斯加权系数中高斯标准差的适用范围;最后,对传统DIC的相关系数进行高斯加权,得到新的相关系数。将所提方法与传统DIC方法和种子点方法分别应用于数字散斑模拟图像的刚体平移试验和Q235试件单向拉伸试验,测量开裂过程中图像的位移,结果表明:传统DIC测量方法不能得到完整的裂缝边缘区域的位移场,而所提方法能够准确测量出完整的裂缝区域的位移变化;传统DIC方法的测量精度仅为0.05像素,而所提方法的测量精度可达到0.01像素;所提方法在高斯标准差为1~6.5像素范围内具有最佳的匹配精度。
In order to solve the problems of poor matching correlation and low measurement accuracy caused by crack bottom color in traditional digital image correlation(DIC)method when measuring crack edge with large deformation,a measurement method of crack edge deformation based on Gaussian weighting coefficient is proposed.Firstly,the position of the Gaussian center in the matching sub-region is automatically adjusted according to the gray gradient sum of squares comparison algorithm.Then,the application scope of Gaussian standard deviations in Gaussian weighting coefficient is determined by constant displacement filling simulation experiment.Finally,a new correlation coefficient is obtained by Gaussian weighting the correlation coefficient of traditional DIC.The proposed method,the traditional DIC method and the seed point method are applied to the rigid body translation experiment of the digital speckle simulation image and the uniaxial tensile experiment of the Q235 specimen,respectively,to measure the displacement of the image during the cracking process.The results show that the traditional DIC method cannot get the complete displacement field of the crack edge area,but the proposed method can accurately measures the displacement variation of the complete crack area.The accuracy of the traditional DIC method is only 0.05 pixels,while the measurement accuracy of the proposed method can reach 0.01 pixels,and it has the best matching accuracy in the Gaussian standard deviation range from 1 to 6.5 pixels.
作者
付白强
王立忠
张振
赵建博
马时凯
韩红亮
FU Baiqiang;WANG Lizhong;ZHANG Zhen;ZHAO Jianbo;MA Shikai;HAN Hongliang(School of Mechanical Engineering, Xinjiang University, Urumqi 830046, China;State Key Laboratory for Manufacturing Systems Engineering, Xi’an Jiaotong University, Xi’an 710049, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2021年第10期174-183,共10页
Journal of Xi'an Jiaotong University
基金
国家自然科学基金资助项目(51865057)。
关键词
数字图像相关法
高斯加权
裂纹边缘
位移场
digital image correlation method
Gaussian weighting
crack edges
displacement field
