胶合金属板脱粘的激光全息检测

全息干涉计量检测方法对材料表面要求比较宽松,特别适用于物体微小形变和微振动的测量.本文采用全息干涉方法检测了胶合金属板的脱胶程度.实验结果表明:铝板脱胶程度越大,对应干板上的干涉条文越细且密集;实验相对误差为3.26%,误差来源为解剖试件时位移量变化以及实测位移量的误差.     

对物体沿散斑片纵向移动二次曝光全息干涉条纹的诠释

从光学几何关系出发,推导了在平行光照明、物体沿散斑片纵向方向微小移动情况下的一种全息干涉条纹的解释方法.该方法可以根据任一瞬间的条纹间距测量物体的位移,并适用于实时全息监测的定量分析,对全息干涉计量术提供有效的条纹解释方法和物体位移的计算方法.     

在粗糙表面上用液晶空间光调制器进行振动测量

为实现在一段时间内连续实时观测振动物体的全息干涉图形,采用覆盖铝箔的喇叭作为振动物体,利用铝箔原有未经特殊处理表面反射的漫反射光成像,并用光寻址液晶空间光调制器(Liquid crystal-sparial lightmodulator,LC-SLM)作为全息记录载体,来实现振动测量。实验中采用时间平均干涉测量法,得到了不同振动频率下物体的干涉图形。同时在连续改变振动物体的振动频率时,可以清晰地观察到物体振动全息干涉图形的变化过程,即近实时的全息干涉图形。     

一种新型的散斑干涉实验

本文介绍了一个用CCD摄像机代替常规的全息干版记录图像．并存储在计算机里进行计算机处理．在电视屏幕上实时观察到干涉散斑场的相关条纹．从而测量出物体微小位移的光、电与计算机相结合的综合实验．     

一种新型的散斑干涉实验

本文介绍一个用ＣＣＤ摄像机代替常规的全息干版记录图像，并存储在计算机里进行计算机处理，在电视屏幕上实时观察到干涉散斑场的相关条纹，从而测量出物体微小位移。是一个光、电与计算机相结合的综合实验。     

一种新型的散斑干涉实验

本文介绍了一个用ＣＣＤ摄像机代替常规的全息于版记录图像，并存储在计算机里进行计算机处理．在电视屏幕上实时观察到干涉散斑场的相关条纹，从而测量出物体微小位移的光、电与计算机相结合的综合实验．     

三维电子散斑干涉载频调制及其在柴油机上的应用

将电子散斑干涉场的三维载波调制技术应用到三维物体变形测量中.用水平方向、竖直方向及垂直试件表面的三路相干光分别照明物体，在水平和竖直方向通过控制反射镜的微小偏转引入载波，实现位移场干涉条纹的调制；利用物体的微小偏转实现离面位移场干涉条纹的调制；结合傅里叶变换法，分别解调出变形场的位相，从而实现了物体三维变形场的精确测量.将该技术应用到柴油机油泵的三维位移测量上，成功测量了油泵的三维位移场.     

基于两步广义相移干涉术的微纳形变测量

基于两步广义相移干涉术,设计微小形变测量实验装置,介绍工作原理和测量方法。采用同轴相移数字全息正交光路,记录形变前后物光、参光、干涉图强度,以两步广义相移干涉算法为基础,恢复原物光相位和表面形貌信息,相减后得到表面形变量。实验结果表明,相对于现有表面微小形变测量方法,提出得方法能够精密测量物体表面微小形变量,方法简单易行,精度可达纳米量级。     

电子散斑干涉载频调制形貌测量方法的分析

根据电子散斑干涉载频调制测量物体形貌的基本原理,物体表面的微小偏转可引入包含物体高度信息的载波干涉条纹。将物体的偏转视为变形,对物体变形与载波干涉条纹之间的关系进行了讨论,得出了离面位移引入载波和面内位移引入含有物体高度信息相位的结论。发现利用典型电子散斑干涉系统测量物体形貌效果最好,并通过实验得到了验证。     

调制光束全息干涉计量的研究

本文提出了干版运动对记录光束的调制作用及其对全息干涉计量的影响,推导了干版运动调制光束双曝光干涉图的光强分布的数学表达式.在对这种调制干涉条纹的理论研究基础上,提出了被测物体三维位移场的调制光束全息分析法.其中干版的运动用参考物体法确定.     

光指针式微小位移测量仪

光指针式微小位移测量仪巧用光路将微小的位移量放大,从光指针终端的标度盘上可以直接读取实际的位移数值.     

Displacement measurements in structural elements by optical techniques

Speckle metrology and holographic interferometry (HI) have been used in several civil engineering applications. We present the results obtained by applying speckle photography (SP) to the study of two quadratic shearwalls with different boundary conditions, and the potential of the technique in the study of this kind of structures is described. The analysis of Young's fringes obtained with this technique at certain points on each shearwall provides the whole field of displacement measurements. HI has been used to measure the three components of absolute displacement, verifying that the bulging phenomenon does not affect the in-plane components when the applied load remains on the same plane as the shearwall. A qualitative analysis is carried out following an electronic speckle pattern interferometry (ESPI) technique. The results obtained by optical techniques are compared to the numerical results obtained by the finite element method (FEM), finding good correlation between them in all the cases.     

基于金刚石色心自旋磁共振效应的微位移测量方法

基于压电陶瓷精密微位移系统的扫描探测技术是目前精密测量仪器进行微纳区域/结构性能测试的核心系统,但压电陶瓷材料存在迟滞、非线性问题,限制了对微位移分辨能力的提升.本文以金刚石氮空位色心为敏感单元,利用电子自旋效应对磁场强度的高分辨敏感机理,结合永磁体周围不同位置对应的磁场强度变化关系,提出了一种基于金刚石氮空位色心电子自旋敏感机理的微位移检测方法.通过建立电子自旋效应与微位移的关联模型,搭建了相应的微位移测量系统.经实验验证,该系统对微位移测试的灵敏度为16.67 V/mm,检测分辨率达到60 nm,实现了对微位移的高分辨率测量.并通过理论分析,该系统的微位移测量分辨率可进一步提升至亚纳米级水平,为新型微位移测量技术提供了发展方向和研究思路.     

Load characteristics of high power sandwich piezoelectric ultrasonic transducers

Based on the equivalent circuit theory, the load characteristics of high power piezoelectric ultrasonic sandwich transducers are studied. Two types of loads are studied. One is liquid load as in ultrasonic cleaning, and the other is solid load as in ultrasonic drilling and machining. The effect of load and structure of the transducer on the resonance frequency of the transducer is analyzed. It is shown that the effect of load on the resonance frequency of sandwich transducers with different structures is different. For liquid load as in ultrasonic cleaning, the effect of the load on the resonance frequency of the sandwich transducer with symmetrical structure is the largest. It is the smallest for the transducer with its displacement node in the back metal cylinder. For solid load as in ultrasonic drilling and machining, the effect of the load on the resonance frequency of the sandwich transducer with its displacement node in the front metal cylinder is the largest. It is also the smallest for the transducer with its displacement node in the back metal cylinder. On the other hand, for some applications, such as ultrasonic drilling, when the lateral dimension of the tool is much less than that of the transducer, its effect on the resonance frequency of the transducer is small. The conclusions are useful in designing vibrating systems for different ultrasonic applications.     

DSPI strain measurement on an externally reinforced bending beam: A comparison of step-by-step addition and pixel shift correlation

A small-scale concrete beam reinforced with an adhesively bonded carbon fiber reinforced polymer (CFRP) plate was subjected to four-point bending. Finite element analyses (FEA) of the bending deformations were carried out to predict strain gradients near the end of the CFRP plate. In order to measure these strains, phase-stepping 3D-digital speckle pattern interferometry was employed. To avoid speckle decorrelation due to the inevitable rigid body motion of the specimen, the load was increased in small increments. Two evaluation schemes for the electronic speckle pattern interferometry phase maps are compared: summing up the measured displacement components load step-by-load step versus regain of the correlation by shifting the final image by an integer number of pixels. Measured strain values are evaluated using a polynomial fit to the measured in-plane displacements and are compared to the FE predicitions. It can be concluded that pixel shift correlation is preferable to summing up load steps for cases of large rigid body motion.     

光纤双向应变-位移点式传感器

选择不同间距的基片自由端和不同长度的自由悬垂光纤研制了利用光纤弯曲损耗的光纤双向应变-位移传感器.该传感器可分别用于测量应变和位移.实验表明:悬臂梁上的应变标准误差约为～26 με.微位移架上的位移标准误差约～0.06 mm.基本满足建筑结构对测量精度的要求.     

Iterative Fourier transform method for phase map recovery in electronic speckle-shearing pattern interferometry

Increasing phase values at the edges of objects under analysis in electronic speckle shearing interferometry (ESSPI) cause errors in the actual recovering methods to obtain the spatially integrated phase. An iterative least minimum squares method is proposed here to recover the phase map from the approximated ESSPI derivatives when the displacement phase is increasing near the object edges. It is based in an iterative Fourier transform method derived from a least-squares phase map recovery algorithm. Experimental results from a rotating cylindrical bar show the validity of our approach.     

基于膨胀法的新型光纤测温仪

提出一种新型的光纤测温传感器。基于热胀冷缩原理,物体长度会随温度变化产生与之成正比的微小变化,采用带光源的光纤测微位移探头测出这个微小变化,可得温度与位移的变化关系,采用光电转换则可输出温度与电流的变化关系。     

Enhancement in flaw detectability by means of lockin temporal speckle pattern interferometry and thermal waves

A lockin method which takes into account the contribution of several modes from the Fourier spectrum generated by a heat load following a triangular waveform is used in temporal speckle pattern interferometry (TSPI) for the nondestructive detection of defects. By defining a parameter to quantify defect detectability, it is demonstrated that the use of this technique improves the detection of hidden flaws located in metal plates.     

Study of shockwave propagation in a metal bar by high-speed interferometry

The work described in this paper is aimed at establishing the profile of the transient displacement of a point on the side of a long metal bar when a compression wave travels along it. The part of the bar to be examined is polished optically flat and is used as one reflector in a conventional two-beam interferometer. The passage of the wave distorts the polished area. The resulting transient fringe pattern, representing the distortion in the out-of-plane direction is recorded by high-speed streak photography. From the records obtained it is easy to derive high resolution graphs of displacement against time.In many cases satisfactory results can be obtained using a small mirror attached to the bar with adhesive, so avoiding the troublesome process of optically polishing part of the surface.