数字图像相关测量钢绞线弹性模量的应用研究-工程力学.pdf

28 卷 9 期 Vol.28 No.9 工 程 力 学 20 11 年 9 月 Sep. 20 11 ENGINEERING MECHANICS 251 文章编号：1000-4750(2011)09-0251-06 数字图像相关测量钢绞线弹性模量的应用研究 * 张 蕊， 贺玲凤，胡 斌 (华南理工大学土木与交通学院，广州 510640) 摘 要：该文利用非接触式数字图像相关方法测量了预应力钢绞线的弹性模量。测量过程中用 CCD 相机记录不 同载荷下钢绞线表面 数字图像，再利用数字图像相关方法对所采集的序列数字图像进行分析从中精确提取不同 载荷下钢绞线表面的纵向平均正应变。根据试验机的载荷信息、钢绞线的参考截面积和由数字图像相关方法测量 的平均正应变绘制出钢绞线 应力-应变曲线，并对应力-应变曲线进行线性拟合计算出钢绞线 弹性模量，为验 证该文方法的精度，研究中对钢绞线进行重复试验，通过获得5 组弹性模量数据，并将测量结果与接触式引伸计 测量结果进行了比较，两者符合得很好。实验结果表明数字图像相关方法可用于预应力钢绞线弹性模量的快速、 精确测量。 关键词：数字图像相关；钢绞线；弹性模量；位移；应变 中图分类号 O348; TU511.3 文献标志码：A ELASTIC MODULUS MEASUREMENT OF STRAND WITRE BY DIGITAL IMAGE CORREALTION * ZHANG Rui , HE Ling-feng , HU Bin (School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510640, China) Abstract: The elastic modulus of strand wires under uniaxial tension is measured using a digital image correlation method (DIC) in this paper. The surface images of the strand wire surface subj ected to various loadings were captured using a CCD camera. DIC is subsequently used to obtain displacement field by correlating the images captured before and after deformation, and then the average tensile strain is obtained by fitting the displacement using a linear plane. The slope of each set of applied stress versus measured strain data is calculated by least-squares linear regression. The elastic moduli obtained from DIC, are compared to that determined from the extensometer, which shows that they are in good accordance with each other. Experimental results clearly show that DIC is suitable for accurate measurement of the elastic modu