小视场下基于可移动3D-DIC的全场应变测量方法

Full-field strain measurement method based on mobile 3D-DIC in a small field of view

由于试件工作环境空间有限,全场应变分析面临着相机光轴和试件表面不垂直和不同区域图像拼接获得的全景图像中存在拼接缝的问题。基于此,提出了基于可移动三维数字图像相关法(3D-digital image correlation,3D-DIC)全场应变测量方法,用于高分辨率形变和应变测量。该方法将双目相机安装在稳定的滑动台结构上,通过控制相机采集叶片不同位置图像,重建试件表面完整图像。提出基于散斑点匹配融合算法,将不同区域图像拼接为叶片全景图像。静态误差分析试验和均匀应变场分析试验被设计验证该方法的有效性。试验结果表明,该方法的横向和轴向应变误差分别为0.98%和1.03%,表明应变分析中具有较高的精度。该方法有效地实现了小视场环境下样本的全场应变测量。

Due to the limited working environment space of specimens,the full-field strain analysis is faced with a problem that the optical axis of the camera is not perpendicular to the surface of the specimen,and there are seams in the panoramic images obtained by splicing images of different regions.Based on this,a full-field strain measurement method based on mobile 3D-digital image correlation(3D-DIC)is proposed for high-resolution deformation and strain measurement.In this method,a binocular camera is mounted on a stable sliding platform,and images of different positions of the specimen are collected by controlling the camera to reconstruct the complete image of the specimen surface.A speckle matching fusion algorithm is proposed to splice images from different regions into panoramic images.Static error analysis test and uniform strain field analysis test are designed to verify effectiveness of this method.The test results show that the transverse and axial strain errors of this method are 0.98%and 1.03%,respectively,indicating that the strain analysis has has high accuracy.This method effectively achieves full-field strain measurement of samples in a small field of view environment.