高分辨率电镜微米云纹法及其应用

文中就云纹干涉法,电子束云纹法,原子力云纹法,扫描电镜云纹法,聚焦离子束云纹测量微区变形的原理和适用性进行了讨论.应用1200线/毫米的云纹光栅并结合云纹干涉法,电子束云纹法,原子力云纹法,扫描电镜云纹法测量QFP和BGA型电子封装组件的热变形.提出一种新型聚焦离子束云纹法,在MEMS结构上制栅形成FIB扫描云纹,成功的实验结果表明这种方法的可行性.     

错位云纹干涉法同步测量三维位移导数场

本文提出一种变载波双曝光错位云纹干涉法,将变形信息的记录过程与错位分析分开进行。通过对一级衍射波引入适当载波后,用双曝光法将变形信息记录在一张底板上,尔后通过滤波分离变形信息及错位处理,实现了三维位移导数场的同步测量。文中给出了较为严密的理论推导,并给出了平面模型静态下的面内和离面位移场测量结果。     

错位散斑云纹法测量应变场

本文建议的错位散斑云纹法是在错位散斑干涉的基础上,通过在光路中附加虚位移的方法获得错位散斑干涉条纹的相减云纹图,从而扣除离面位移导数,获得单纯的面内位移导数场即应变场。典型实验证实这一方法可以有效地获取全场应变条纹图。     

三维位移场(U,V,W)实时观测的云纹干涉法

本文将一特殊布置的云纹干涉系统和一垂直入射试件栅的麦克尔逊干涉系统组和起来,利用云纹干涉系统测量两个面内位移分量U、V,垂直入射的麦克尔逊干涉系统测量离面位移分量 W。调节云纹干涉系统中入射光的入射角,使正、负一级衍涉波的传播方向偏离开试件栅法向一微小角度,从而使一级衍涉波的频谱点与麦克尔逊干涉系统中的零级衍涉波的频谱点在频谱面上分开。利用小反射镜的反射来改变一级衍射波的传播方向,从而使我们在三个彼此分开的成像面上同步实时观测到三维位移场的条纹图。文中给出了严格的理论推导和实验验证。     

云纹干涉法同时测定三维位移场(U_0,U_(45),U_(90),ω)

本文介绍了用云纹干涉法同时获得三维位移场——面内位移(U_0,U_(45),U_(90))和离面位移(w)的两种方法:实时观测法和加载波条纹的差载法.前者可一次加载,分别观测各个位移分量条纹图;后者可用一张底板同时记录全部三维位移信息,通过光学滤波分离出各位移分量条纹图。测试方法和计算都很简便,不仅能测静荷,同时也可测动荷,文中还介绍了实验用的仪器,给出了实验结果。     

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。     

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。     

云纹干涉测量法进展

引言用云纹(Moire)法测量位移是极为引人注目的。云纹法通过观察等位移线的等值线图的分布场,确定变形体的位移场。严格地讲云纹属于几何效应,对弹性体,非弹性体,各向同性体及各向异性体的位移同样地反映良好。已经研究成功测定结构及结构部件面内及离面位移的多种云纹技术,但是几乎所有以前的研究工作使用的都是40线/毫米即1000线/英寸的较粗的光栅,或者更粗一些。这只能测定较大的位移,例如高延性材料的面内弹性位移及结构材料的非弹性位移。     

微电子机械系统（MEMS）面内位移的扫描离子束云纹法实验研究

本文提出应用扫描离子束云纹法测量微电子机械系统面内变形的新方法。对该方法的测量原理以及实验技术进行详尽地阐述，通过平行云纹典型实验对本方法的测量精度进行了检验。成功地将扫描离子束云纹法应用于微悬臂梁表面氧化层随时间生长所引起的变形测量，实验结果表明了该方法的可行性。     

复合材料断裂力学参量的实验测定

本文采用三维云纹干涉仪同步测量含裂纹复合材料弯曲板的面内位移场及离面位移场，并对离面位移场云纹图进行计算机自动采集和处理，编制了云纹数字图像处理软件。文中推导了正交异性复合材料弯曲问题的离面位移场表达式，得到了弯曲板裂纹尖端位移w与应力场强度因子K1的关系式。通过实测位移，结合裂尖位移场推导出应力强度因子K1值。     

A dynamic moiré method for deformation measurement of curved surfaces

A simple method is proposed for obtaining moiré patterns, and information is given on the deformation of curved surfaces. The experimental arrangement is based on the projection-moiré principle and consists of a projector and a camera. A transparent object, e.g., a shell with line gratings, is projected onto the focal plane of this projector and superposed there with a reference grating which describes the undeformed state of the curved surface in the form of a transparent picture. Moiré patterns are obtained by simultaneously superposing the projected line grating in the shell's deformed state and the reference grating. They present a general picture of the behavior of the object during loading, such as during impact if the patterns are recorded with a high-speed camera.     

Experimental analysis of crack tip fields in rubber materials under large deformation

A three-nested-deformation model is proposed to describe crack-tip fields in rubber-like materials with large deformation.The model is inspired by the distribution of the measured in-plane and out-of-plane deformation.The inplane displacement of crack-tip fields under both Mode I and mixed-mode(Mode I-II) fracture conditions is measured by using the digital Moire’ method.The deformation characteristics and experimental sector division mode are investigated by comparing the measured displacement fields under different fracture modes.The out-of-plane displacement field near the crack tip is measured using the three-dimensional digital speckle correlation method.     

An electron moiré method for a common SEM

In the electron moiré method, a high-frequency grating is used to measure microscopic deformation, which promises significant potential applications for the method in the microscopic analysis of materials. However, a special beam scanning control device is required to produce a grating and generate a moiré fringe pattern for the scanning electron microscope (SEM). Because only a few SEMs used in the material science studies are equipped with this device, the use of the electron moiré method is limited. In this study, an electron moiré method for a common SEM without the beam control device is presented. A grating based on a multi-scanning concept is fabricated in any observing mode. A real-time moiré pattern can also be generated in the SEM or an optical filtering system. Without the beam control device being a prerequisite, the electron moiré method can be more widely used. The experimental results from three different types of SEMs show that high quality gratings with uniform lines and less pitch error can be fabricated by this method, and moiré patterns can also be correctly generated.The project supported by the National Natural Science Foundation of China (10662005) and JSPS fellowship in Japan. The English text was polished by Keren Wang.     

高频光栅节距误差的采样云纹法分析

使用采样云纹法来研究高频光栅节距的畸变程度.用电子束刻蚀的3922 line/mm的平行光栅,对其高分辨率扫描电镜图像进行采样和相移分析,得到对应的相位分布,进而转化为相对误差.对于正交光栅,分别进行水平和垂直方向线性滤波后转化为对应的平行光栅,进而得到相对误差分布,并提出误差统计分析来评价光栅质量.理论和实验验证表明采样云纹法可为高频光栅提供评价手段.     

Surface topography by multisource moiré patterns

Moiré patterns produced by interference of a series of periodically arranged linear light sources with a line-specimen grating of similar pitch are located at a plane parallel to the sources and the specimen grating and at some distance away from these planes. A transparent or reflecting specimen located at a distance from the specimen grating distorts the image of the multisource projected on the specimen grating due to its surface irregularities and forms a moiré pattern. This pattern yields the partial-slope contours of the topography of the specimen along a direction normal to the lines of the grating. Two such contour patterns taken at mutually perpendicular directions are sufficient to yield the complete topographic picture of the surface. The method was used for determining gradients of thickness variations in two-dimensional specimens due to lateral contraction. The technique is highly accurate in determining the values of thickness in such cases, since the integration of the slope of thickness variation along any traverse of the specimen is a steady and accurate process.     

Moiré interferometry at VPI & SU

A relatively easy technique for producing high-frequency gratings on specimens extends moiré techniques into the high-sensitivity domain. Whole-field patterns of inplane displacement components are obtained with grating frequencies of 1200, 2400 and 4000 l/mm (30,480, 60,960 and 101,600 l/in.). Moiré interferometry is a case of two-beam interference, characterized by extensive range, excellent fringe contrast and fringe localization on the specimen surface. It is a reflection technique, compatible with opaque specimens and live observation of deformation.     

Hole-drilling method using grating rosette and Moiré interferometry

The hole-drilling method is one of the most wellknown methods for measuring residual stresses. To identify unknown plane stresses in a specimen, a circular hole is first drilled in the infinite plate under plane stress, then the strains resulting from the hole drilling is measured. The strains may be acquired from interpreting the Moire signature around the hole. In crossed grating Moire interferometry, the horizontal and vertical displacement fields （u and v） can be obtained to determinate two strain fields and one shearing strain field. In this paper, by means of Moire interferometry and three directions grating （grating rosette） developed by the authors, three displacement fields （u, v and s） are obtained to acquire three strain fields. As a practical application, the hole-drilling method is adopted to measure the relief strains for aluminum and fiber reinforced composite. It is a step by step method; in each step a single laminate or equivalent depth is drilled to find some relationships between the drilling depth and the residual strains relieved in the fiber reinforced composite materials.     

A new optical system for moiré methods

A new optical system for moiré methods is proposed in which the light path from the model grating and that from the master grating are diffent. They are combined by mirrors to form moiré patterns. Its application to Ligtenberg's reflective moiré method extends the method to dynamic problems and also facilitates the use of linearmismatch fringes. It can also be applied to in-plane moiré method in cases where deformation is large and diect contact with model grating is to be avoided.     

Simultaneous recording of fringe patterns with one camera

A novel method to separate and simultaneously record the Moiré interferometry fringe patterns of three deformation fields with only one CCD camera is developed; details of its operation principle, key points and error analysis are presented. With this technique, the deformation inU, V andW fields can be measured simultaneously, so dynamic test with comprehensive information can be performed. The advantage of this technique over other similar techniques lies in its simplicity, easy implementation and low cost. An application of this technique is given to show its feasibility. Technical problems that may be caused with this technique are also analyzed.     

Dynamic Thermal Deformation Measurement of Large-Scale, High-Temperature Piping in Thermal Power Plants Utilizing the Sampling Moiré Method and Grating Magnets

Fast and accurate deformation measuring techniques show promising potential for monitoring high-temperature piping and other machinery in the energy sector, such as in thermal, steam, or nuclear power plants. Optics-based, nonintrusive, and real-time monitoring systems are critical for preventing high-temperature steam leaks, unexpected accidents, explosions, and other failures that can have catastrophic consequences for the power supply, the workers, and the public. In this study, a dynamic thermal deformation measurement technique utilizing the sampling Moiré method and grating magnets is developed for large-scale, high-temperature piping in a thermal power plant. Because of the high temperature of the piping of nearly 300 °C several 100 mm by 100 mm ferrite magnets were placed to select locations of the high-temperature piping. In each ferrite magnet, a regular, two-dimensional binary grating pattern with a pitch of 15 mm was painted on the surface, and the grating magnets were used as the reference grating to analyze the small in-plane displacement distribution using the sampling Moiré method. A compensation method of misalignment angle is also proposed to improve the measurement accuracy. The effect on vibration remove, mirage due to conversion in air, wide angle of camera lens, and compensation of misalignment angle, are discussed. The experimental results showed that our measurement technique is suitable for evaluation of high-temperature, large-scale infrastructure.