本文利用抽样莫尔法,对材料变形进行了精密测量。将罗琦光栅紧贴在试件表面,使其和试件材料一起变形,然后用CCD摄像机获取在不同拉伸状态下的离焦变形条纹图。取出其中一幅变形条纹图,采用抽样和双线性插值等操作获取该状态下的多帧相移莫尔图,通过相移法计算莫尔相位,经相应公式的计算,得到材料的位移和应变分布。文中给出了抽样莫尔法基本原理,推导了位移应变计算公式并给出了实验结果。实验结果表明,由于抽样莫尔法只需一幅变形条纹图并结合相移技术获取材料的位移和应变等数据,因而能以较快速度和较高精度实时完成不同变形状态下材料的位移和应变等重要特性的分析。本文为动态过程中材料的变形提供了一种精密测量的方法。
Sampling Moiré method was applied to measure the material deformation accurately. Lodge grating was attached to the surface of the specimen and specimen material with its deformation together, and then different tensile deformation fringe pattern was obtained under defocus by CCD. A deformed fringe pattern was taken out. By using operations such as sampling and bilinear interpolation for the state, multi-frame phase-shifting Moiré maps were acquired. And material displacement and strain distribution were obtained with phase shift method and corresponding formulas. The basic principles of sampling Moiré method were presented, strain displacement formula was derived and experimental results were given. The results show that sampling Moiré method combined with phase-shifting technology is accessible to the material displacement and strain data only using a deformation fringe pattern, which can measure the displacement, strain and other important characteristics analysis with real-time, high accuracy and fast speed. This method is a precise measurement for deformation of the material under dynamic process.