TRIANGULAR AND v 2 GRATINGS FOR THE MOIRÉ TECHNIQUE

Methods for constructing two new types of grating for the moiré technique are described, their use is illustrated in application to a simple beam, and the range of measurable strains is established. In certain circumstances the use of these gratings presents a means of accurate analysis without recourse to elaborate equipment.     

DIRECT MEASURE OF STRAIN BY AN EXTENSION OF MOIRÉ

An extension of the Moiré theory yields two new methods of strain measurement based on diffraction of light. These methods have the advantage of giving directly (without graphical or numerical derivation) the strain with a better accuracy than the classical Moiré technique.     

THE MOIRÉ EFFECT APPLIED TO EXPERIMENTAL STRESS ANALYSIS

This paper summarises the applications of the moire effect to stress analysis problems and enumerates its advantages over the conventional grid techniques.     

泰曼-电视-微机系统非球面面形测试

本文用He-Ne激光器作光源,把电视摄相机(或CCD摄相机)和微机与泰曼-格林干涉仪结合,组成泰曼-电视-微机系统。利用法线象差补偿法检测非球面面形的原理,根据三个干涉图法,对非球面面形自动扫描、分析,并在计算机的监视器上绘制出被检非球面面形的二维等高线图和三维面形。为了扩大测试范围,设计了万能补偿器,可检测一定范围的抛物面,补偿精度可达0.01λ,也可检测椭圆面和双曲面。     

TENSILE IMPACT DELAMINATION OF A CROSS-PLY INTERFACE STUDIED BY MOIRÉ PHOTOGRAPHY

Abstract Impact induced delamination along a cross-ply interface in carbon fiber/epoxy laminates is studied by high resolution moiré photography. The specimens were loaded in a tensile split-Hopkinson bar giving mode I dominated fracture, and a high speed camera captures images during loading and delamination. The resulting moiré fringes are analysed to produce full field displacement maps of the area around the loaded and propagating crack tips. The displacement map prior to failure shows good agreement with numerical solutions, calculated using a 3D self-adaptive p-version of the finite element method. The calibrated finite element solutions are then used to give further information about the matrix cracking zone size around the crack tip and the energy release rate. In comparison to quasi-static loading, tensile impact loading was found to increase the failure load and the resulting energy release rates; some physical explanations for this behaviour are discussed. It was concluded that the procedures presented have good potential for further determination of rate dependent material properties in carbon/fiber epoxy composites.     

定量测定钢中奥氏体和马氏体的X射线新方法

为了解决应用X射线衍射技术进行精确、定量测定含有织构和碳化物的钢铁材料中的残余奥氏体或马氏体问题,弥补国家标准（GB/T 8362-1987）和其它方法之不足,提出一种新方法.该方法操作简单,结果准确,主要用于测定钢中奥氏体和马氏体,也适用于测定其它金属材料中的同素异构体.     

拉曼光谱测定变压器油中溶解气体的浓度

提出一种通过监测变压器油中熔解甲烷，乙炔气体特征拉曼散射谱峰处的拉曼散射信号强度，以实现变压器中溶解甲烷，乙炔气体浓度在线测量的新方法。     

氧化法奥氏体晶粒度试样的制备

氧化法显示钢中奥氏体晶粒度 ,是评定钢铁材料奥氏体晶粒大小的质检方法之一。由于试样氧化是在热处理炉中进行 ,而加热处理后试样表面只能形成极薄的有效分析层 ,磨制试样时稍有操作不慎 ,很容易把有效分析层破坏掉。为防止和避免误操作 ,其制备方法是 :(1)试样未氧化之前 ,被检面用金相砂纸打平磨光 ,然后在海军呢或 2 5 0～ 30 0目混合磨料的蜡盘上磨抛 ,以隐约照人为度。(2 )氧化时将试样抛光面朝上 ,置于加热炉中央 ,同时在试样下垫一块耐火材料并洒点砂子以防试样和耐火材料粘连。(3)试样氧化完毕后 ,直接用蜡盘或细砂纸轻轻打磨 ,时…     

相敏检波技术测量微弱信号的原理与方法

介绍用相敏检波技术测量直流微弱信号的方法,并在理论上作了较为详细的分析。实验结果表明:其检测灵敏度可达0.5μV,测试精度优于±0.5％。     

ATRP法合成PMMA-b-PS-b-PFx-14三嵌段共聚物

首先通过原子转移自由基聚合(ATRP)得到了末端含卤素的聚甲基丙烯酸甲酯，以这种PMMA为大分子引发剂，引发苯乙烯的ATRP反应，得到了末端含卤素的PMMA-PSt双嵌段共聚物。再以这种双嵌段共聚物大分子为引发剂，引发含氟丙烯酸酯Fx-14的ATRP反应，得到了一种PMMA-PSt-Fx-14三嵌段共聚物．通过GPC、核磁、粘度等数据证实了该聚合物的结构，并详细讨论了由于PMMA-PSt-Fx-14在溶液中的线团行为所产生的GPC测试中出现的特殊现象。     

等离子体技术对高分子材料的表面改性

综述了等离子体技术对高分子材料的表面改性,介绍了其最新研究进展并展望了其发展前景。     

用轴端漏磁测量异步电动机参数的探讨

主要研究了异步电动机的轴端漏磁场及其转子频率，转速和转差率的测量原理，并探讨了事存在的几个问题和解决的办法。     

羊毛的等离子体刻蚀改性探讨EI

运用等离子体刻蚀方法对羊毛纤维、纱线及织物进行改性处理。结果表明:这种改性方法对于改善羊毛的抗静电性和导电性,提高羊毛纤维的吸湿性和防缩绒性,尤其是对改善毛纱的强力,具有积极的作用。实验发现,毛织物的等离子体刻蚀处理,有助于织物硬挺度和丰满度的改善和增加织物的表面摩擦作用。作者认为等离子体刻蚀改性处理具有一定的实用意义。     

DISTRIBUTION IN AN EXTRUSION CONTAINER, FOUND BY THE SANDWICH TECHNIQUE

Commercial Perspex and "Perspex" of zero birefringence are applied in an investigation by the sandwich technique of the stress in a transverse section of a container from which lead is extruded through a die. The use of commercial Perspex in this application is shown to give rise to errors which are avoided by the new material of zero birefringence. The principal stresses in the birefringent layer of the sandwich are evaluated.     

用超声波技术测量螺栓轴向紧固应力

超声波速度会因材料中加载应力而产生微小的变化，这一现象特别适用于测量螺栓的轴向应力。根据螺栓的轴向应力与超声波传播时间变化率的关系，作者研究了一种可直接测量螺栓轴同应力的仪器。实验结果显示，本项技术十分适合现场的实际应用。     

GPS高层建筑物常荷载振动测试的小波分析

具有高采样率的GPS接收机的出发,使得GPS技术可以用于大型工程结构（如：大桥,高塔和高层建筑物等）的动态位移监测,其突出优点是GPS可以直接测定工程结构的绝对位移以用于结构的动力特性评估。但应用GPS技术也有其弱点和不足,譬如GPS技术本身的各类误差影响源,必须有效地消除。对于高层建筑的动力特性研究,由于GPS基线可以尽可能地设置得短些,所以其关键的误差影响源于多路径。本文主要研究深圳地王大厦常荷载条件下结构振动GPS测试的有关问题,由于常态下振动的幅值只有1－2毫米,被其它影响源所掩盖,一般难以识别。本文采用小波分析法进行处理,可以有效地识别和提取微小振动,取得很好的效果。