应变测量的光栅法

本文提出一种新的应变测量方法。用模压全息光栅作为应变传感器，测量光栅衍射点空间位置的变化量，直接获得应变或应力分量。全息光栅的模压制作，可以大幅度地降低成本。视频技术与微机技术的运用可以自动地获得应变和应力的数值。     

一种新的全场应变光学测量方法

采用光栅衍射、光学全息、显微图像分析等技术，本文提出了一种用于固体表面应变直接测量的新的光学方法，并把这一方法应用于铝合金试件的单轴拉伸试验。实验结果表明：该方法的应变测量灵敏度为８×１０－５。     

激光光栅显微图像检测技术及其应用

介绍一种可以用来测量曲面试件表面应分量（εｚ,εθ,εｚθ）的激光光栅显微图像检测技术（ＩＧＭ）,它能实现从小应变到大应变全过程的高精度定量测量。我们将这一技术成功地应用在铁基形状记忆合金（ＦＳＭＡ）管接头的结构设计中,在这项研究中,首先在管接头结构表面制作了变形的载体－位相型干涉光栅,由结构表面产生的衍射光通宵我学系统后形成新的干涉光栅,我们利用数字图像系统接收了逆相变前后各自的干涉图像,采用带     

光栅应变法的误差分析与改进

将光栅制作于试件表面作为应变传感器，激光束照射试件被测点所产生的衍射图案随该点的变形发生变化。测定衍射图案的变化可以直接计算出被测点的变形。本文分析了该方法中公式简化、离面转角、离面位移引起的误差，结果表明后两个因素的影响不容忽视。本文还对误差的减小和消除进行了讨论。     

光纤光栅传感器对钢筋混凝土内部应变的测量及温度效应的研究

本文应用光纤光栅传感器实现了对钢筋混凝土试件内部应变的测量．试验不仅就应用光纤光栅进行混凝土结构内部应变测量的技术、工艺进行研究，还通过设计温度控制试验，考察了光纤光栅传感器的温度补偿问题，以及横向应变对测量结果的影响．     

埋入式封装的光纤光栅传感器应变传递分析

推导了布拉格光纤光栅传感器所测应变与实际结构应变的关系,得出了平均应变传递率并与实际试验结果进行比较. 根据应变传递率确定了光纤的临界粘接长度，并推导了多层粘接时的应变传递情况，讨论了影响应变传递率的因素. 结果表明，光纤光栅的粘贴长度必须大于临界粘贴长度，且光纤光栅传感器所测应变需要加以修正才能得到实际结构应变.     

岩石变形光纤光栅传感检测的应变传递分析

岩石变形过程可以通过光纤光栅的表面粘贴法进行检测。建立了考虑表面凹槽时的应变传递模型,经过力学分析得出了应变传递方程及传递系数的表达式;在MTS伺服机上进行了单轴压缩实验,借助光纤光栅对加载过程进行了测试。结果表明,传递方程与粘贴层厚度均匀分布时的方程形式相同,只是特征值k不同;换算后光栅的轴向应变与MTS位移计吻合很好,相对误差仅为3.2%;环向测试优于MTS的环向应变计,而两种方法都明显地优于应变片。实验验证了所建模型的正确性。经应变传递换算后,通过光纤光栅可以实现岩石变形过程中与MTS精度相当的高精确测试。     

遥测自动云纹引伸仪——实时位移测量系统

云纹法是一种新的位移场或应变场测试技术，本文采用云纹法论述的遥测自动云纹引伸仪系统包括云纹引伸仪、位移信息转换和传输装置以及显示接收监测台。由于采用了轮形光栅从而使引伸仪突破了传统的测量限制，从理论上讲，量程可达无穷大。     

云纹／光栅测试技术的几点讨论

本文用信号处理的方法系统地阐述了云纹／光栅测试技术。以面内云纹／光栅测试为例，首先说明了光栅是位移和变形信息的空间载体；位移和应变分别是对载体的相位和频率调制；而云纹现象则是试件栅频谱向零频处平移的结果或说云纹是对光栅载体信号解调的过程；进而讨论了云纹技术与光栅技术的本质区别。其次分析了云纹／光栅测试系统的性能，讨论了条纹分析方法及数字图象处理手段对云纹／光栅系统的测试精度、灵敏度、空间分辨率的影响。     

基于Bragg光纤光栅的位移-应变传感器分析

光纤光栅传感器技术应用于力学测试是国内外正在发展的一门新技术.本文基于光纤光栅传感的基本原理,介绍了一种用于位移测量的应变传感器,测得应变与位移变化具有良好的线性特点,重复性好;对该传感器的测量过程进行了有限元模拟,并与实验值进行了比较.     

光栅应变法的图象处理技术

本文应用数字图象处理技术，对光栅应变法图象进行处理，提出了一种简捷的重心算法，使整个图象处理过程快速简单，自动化程度高，并能保证测量精度，使光栅应变法便于实际测试应用。     

APPLICATION OF GRATING DIFFRACTION IN STRAIN MEASUREMENT

In this paper a new technique for measuring strain is presented.Usinggrating as the strain sensor,we can obtain strain and stress components by measuringthe deformation of the space position of diffraction spots.The cost of the hologra hicgrating by embossing is much reduced.By using the video and computer techniques thestrain and stress Values can be obtained automatically.     

一种基于应变模态分析的舰船分布式挠曲姿态测量方法

针对舰船所处的恶劣环境，以及舰船导航和武器系统对姿态测量精度日益提高的要求，根据应变模态分析理论，建立了应变信息与姿态信息的变换关系，并提出了利用光纤Bragg光栅(FBG)传感器测量甲板的应变，求取由挠曲变形引起的姿态信息误差的方法。通过对简易模型的实验，验证了这种方法是有效的并且具有较高的精度。     

Grating interrogations: from small to large strain measurement

Our purpose is the direct strain measurement from the interrogation of a crossed grating marked on the surface of a specimen. The observation of the object through a master grid (as in moiré method) is replaced by a direct characterization of the pattern using a Fourier transform. This gives direct access to the modification of the pitches which leads to quantification of the strain without the intermediary of a fringe pattern. The comparison between the undeformed and deformed states allows the determination of the magnitude and orientation of principal strains and of the local rigid-body rotation. We describe three analysis techniques, one using the diffraction phenomenon, another utilizing a numerical spectral evaluation and third combining diffraction and phase-shifting procedure. These grid interrogations have different domains of application and a suitable choice of these analysis techniques allows a very large measurement range (10^–5 to high strain according to the grating resistance).     

Strain tensor for large three-dimensional surface deformation of sheet metal from an object grating

Grating techniques are used to determine the three-dimensional deformation and the tangential strain of sheet metal. A grating is fixed on the surface and taken by stereo CCD cameras in different deformation states. By suitable line-following software, the grating coordinates in the images are determined with subpixel accuracy. Using photogrammetric methods, the three-dimensional coordinates are calculated from the image coordinates. The strain usually is determined by means of a deformation gradient, which is calculated from every deformed triangle. In this paper, the gradient is determined in the center of four neighboring meshes using a polynomial approximation of the displacement function in a reference position. The influence of the nontangential deformation is considered. By simulation, a flat sheet metal is deformed to a rotational symmetric surface. The difference of the known exact strain is compared with the numerically derived strain with respect to different grating pitches. The proposed method yields good results even in the case of large spatial deformation. It is applied to the deformation of a hatlike test specimen.     

测量悬臂梁试件截面转角的贴片光栅法

本文应用光栅的衍射行为提出了测量悬臂梁截面转角的方法,给出了普遍公式,并通过实验验证,结果很好.     

Advances in scanning electron microscope moiré

The scanning electron microscope (SEM) moiré method for microscopic measurements based on electron beam lithography and an SEM has been well developed. Although it has been a reliable method, some drawbacks exist: reinforcement effects, complicated processing and low sensitivity. To improve the SEM moiré method, new grating-casting techniques and a fringe-viewing technique must be developed. In this study, a carbonaceous grating technique and a total imaging technique are introduced. Accordingly, there are two techniques available for grating-casting (i.e., the carbonaceous grating technique and the existing lithography grating technique) and three techniques available for fringe viewing (i.e., the total imaging technique, the existing, monitor viewing technique and the existing photographic viewing technique). A total of six new imaging techniques of SEM moiré methods are available for microscopic measurements by combining one technique from each of the two groups. This study demonstrates the feasibility of the individual techniques and discusses the characteristics and limitations of each. Based on the presented total imaging technique, the sensitivity of the moiré method is only dependent on the frequency of specimen grating. Because it can be made as high as 10,000 lines/mm, the SEM moiré method can achieve sensitivity as high as 0.01 percent.