使用拍照手机的数字图像相关测量系统在实验力学教学中的应用  

APPLICATIONS OF CAMERA PHONE-BASED DIGITAL IMAGE CORRELATION SYSTEM IN THE TEACHING OF EXPERIMENTAL MECHANICS

作　　者：俞立平[1] 潘兵[1] YU Liping;PAN Bing(Institute of Solid Mechanics,School of Aeronautic Science and Engineering,Beihang University,Beijing 100191,China)

机构地区：[1]北京航空航天大学航空科学与工程学院固体力学所,北京100191

出　　处：《力学与实践》2021年第2期294-301,共8页Mechanics in Engineering

基　　金：国家自然科学基金资助项目(11925202,11872009)。

摘　　要：为了加深对力学知识的理解以及激发学生对实验力学的兴趣,本文介绍了基于拍照手机和二维及三维数字图像相关方法相结合的变形测试方法。首先以经典的单向拉伸实验为例,应用拍照手机和二维数字图像相关法测量了铝合金试样的载荷-应变曲线,并引入"补偿法"思想消除手机成像系统的成像误差以实现高精度的应变测量。随后,利用基于单个拍照手机和伪立体视觉成像的三维数字图像相关系统测量了规则圆柱面和非规则曲面的三维形貌,并测量了充气球体在放气过程中形貌变化和三维全场变形。实验结果直观地显示了充气球体表面在放气过程中的变化规律。这种易于获取、低成本且便携性好的数字图像相关测量系统不仅大大减少了系统搭建的硬件投入,更提高了实际测量的便利性和效率,因此有助于在条件有限的高等院校和研究机构中开展实验力学教学。To help students better understand mechanics and to stimulate students’interest in experimental mechanics,this paper proposes experimental methods based on the camera phone imaging and the digital image correlation for two-dimensional(2D)and three-dimensional(3D)deformations measurement.Taking the typical tensile test as an example,we first determine the load-strain curve of an aluminum specimen using a camera phone and the two-dimensional digital image correlation(2D-DIC).To achieve the high-precision strain measurement,the idea of"compensation"is introduced to eliminate the errors associated with the camera phone image.Subsequently,the three-dimensional digital image correlation(3D-DIC)system based on a single camera phone is developed to determine the shape profiles of a cylinder and irregular surfaces,as well as the topography change and the 3D full-field deformation of the inflatable sphere during the deflation process.The experimental results intuitively show the change of the surface of the inflatable sphere during the entire deflation process.The cost-effective and ultra-portable camera phone-based DIC systems not only greatly decrease the hardware investment in the system construction,but also increase the convenience and the efficiency of 3D deformation measurements,with a great potential in the teaching of experimental mechanics in resource-limited universities and research institutes.

关 键 词：数字图像相关法 智能手机 变形测量 实验教学 

分 类 号：O348.1[理学—固体力学]