数字激光散斑法测量杨氏弹性模量的实验设计

Experimental design of Young's elastic modulus measured by digital laser speckle

激光散斑可以自由空间传播或成像的方式产生,数字激光散斑具有广泛的应用前景。本文着重阐述了利用数字激光散斑测量散射体位移的光路和方法,并给出了相关算法。随后设计了采用数字激光散斑测量杨氏弹性模量的实验系统,并给出了定标和测量方法。利用此方法,测量了钢丝的杨氏弹性模量,测量结果的精度和不确定度与光杠杆法相当。最后分析了误差的来源和测量中的关键因素。

Laser speckle can be produced by transmitting in free space or imaging,so digital laser speckle has wide application prospects. The light path and method of the scatterer displacement measured by digital laser speckle are introduced,and the correlation algorithm is given. Then the experimental system measuring Young＇s elastic modulus by digital laser speckle was designed,and the calibration and measuring methods were giving. Using this method,the Young＇s elastic modulus of steel wire was measured. The results show the accuracy and uncertainty are similar to that of optical lever method. At last,the error sources and key factors in measurement are analyzed.