基于液晶体的大错位量散斑相移技术研究

系统地分析了大错位量散斑干涉术测量离面位移的原理，并结合晶体光学理论详细分析液晶体的相移过程．同时从理论上剖析了沃拉斯顿棱镜的错位机理，从而构造出一种新的基于液晶体实现大错位量散斑相移技术的测试系统。采用该检测系统对结构实体混凝土在不同养护时间情况下的力学行为进行测试研究。实验结果揭示：随着养护时间的增加，混凝土结构的力学性能指标也相应增加，但在养护21天后，混凝土结构材料的弹性模量和结构强度都达到某一稳定值(即标准试样在同等养护条件下的实验室测量值)。并且也发现该技术使用方便，检测时受环境的影响小，可以实现现场在线原位实时无损检测，并能够得到非常真实的检测结果，从而可以实现更精确的定量计算。

Large-Shear Digital Speckle Interferometry Based on Liquid Crystal Phase Modulator

The large-shear digital speckle interferometry are employed to measure the out-of-displacement of concrete structure. Based on the phase-modulation theory of liquid crystal variable retarder, a retarder is an optical device that resolves a light wave into two orthogonal linear polarization components and produces a phase shift between them. The liquid-crystal phase shifter is successfully incorporated into the large-shear digital speckle interferometry system to enhance the measuring sensitivity and accuracy. From the experiment used to measure the out-of-displacement of an object, the optimum performance of the method is confirmed. In the meantime, the new technique is provided to evaluate the mechanical behavior of concrete structure with different curing time with non-contact, high accuracy, full-field, real-time and in-situ. The experimental results show that the strength of concrete structure will be enhanced as its curing time goes on, and after 21 days the strength value will be approaching to the design value.