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提出了用超声散斑干涉法来测量物体的位移，并且基于数字干涉和相移-频移技术对超 声散斑数字干涉测量法进行了初步的理论推导. 为了验证理论分析的结果，对一铝试件进行 了离面位移和面内位移的试验测量. 试验结果显示理论分析是正确的，在测量位移和变形时 此方法是有效可行的.     

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。     

激光散斑应用于变形测量

在激光全息照相的照片上,由于激光的相干性,造成了随机分布的斑点,大约是微米量级的,这就是散斑效应.自从1968年全息干涉计量蓬勃发展以来,散斑也吸引了很多人去研究它的应用.因为人们确信,散斑是一种干涉现象,对这种干涉现象,一定会找到它的应用.1969年 Leen-dertz 提出"散斑干涉"的方法,1970年 Archbold 等提出了"散斑照相"的方法.以后,大体上由这两种思想发展了一系列的方法和技术.直到现在,它们在变形测量及其它应用中,仍然是很活跃的领域.     

电子错位散斑研究

本文从理论上分析了错位散斑实现电子干涉的可行性,推导了摄象机光靶接收的错位散斑的光强表达式,分析了电子干涉条纹的可见度,提出并实现了电子错位散斑技术的三种方法,即实时法,双曝光法和实时时间差法。获得了位移梯度等值条纹的电子干涉图。     

时间序列散斑干涉技术的发展及应用

当用相干光照射一个连续变形的漫射物体表达时，由漫射物体表面散射所形成的物光与一参考光干涉，在其干涉的区域即可形成一随时间变化的散斑场，连续采集这一时变散斑场，并通过时间域分析，即可获得被测物质表面所对应的时变位移场，本文在作者研究的基础上，介绍序列散斑计量技术中所发展起来的几种计量方法，探讨它们的计量特性及其发展方向，并同时给出这些计量方法在时变场检测中的一些应用成果。     

散斑全息干涉法测量面内位移和应变

测量面内位移和应变有很多方法,诸如莫尔条纹法、全息干涉法、激光散斑干涉法等属于近代光学方法。其中莫尔条纹法需要在试件表面布上极细的网格,这在工艺上较难;而全息干涉法又需沿不同方向进行全息照相,要求较高,数据处理的程序也较繁复.最近国外采用激光散斑干涉来测量面内位移和应变,发展很快。激光散斑干涉法亦有多种。成象散斑干涉是记录被相干光照明的物体经透镜成像后所形成的具有斑点图信息的物体象,照明光可用单光束或多光束:光栏也可以是单孔或多孔。我们曾采用单光束和单孔成象的散斑干涉法对游标盘的转动进行了定标试验。另一种散斑干涉法是直接将感光片和被测物表面贴近,并牢靠地固定其相对位置.再用一束准直激光直接从感光片背面射入。由于照明光与物体表面的漫反射光是从接近180°的方向射到感光层,因而感光片记录的信息中不仅有斑点图信息,而且还包含有能实现白光再现的全息图信息,我们暂且称其为散斑全息干涉法.本文主要介绍散斑全息干涉的物理原理和它的实验方法,并利用杨氏干涉法对游标盘转动后的位移量定标和对单向拉伸的矩形板中的圆孔应力集中系数进行了定标,取得了实验结果。此外,还指出了散斑干涉法的缺点和局限性。     

用于位移、应变分析的激光散斑干涉的全场分析

本文叙述用于位移、应变分析的激光散斑干涉的全场分析法,提出了三种新的散斑照相法:十字缝光阑法、矩形多孔光阑法、移动或旋转孔光阑法.对这些方法进行了理论分析和实验验证.结果表明;采用这些方法进行散斑照相,在全场分析时可以有很宽的滤波变化范围而同时有较高的观察光强,因而可以获得清晰的、位移灵敏度可变的类似于全息干涉图一样的位移场分布图,这无疑为散斑干涉的应用提供了很大的方便,使全场分析法更具有现实性.     

散斑光弹性干涉法

全息干涉法和普通光弹性法相结合产生了全息光弹性法。与此类似,本文建议将散斑干涉法和光弹性相结合形成具有一定特点的散斑光弹干涉法。近十几年来,散斑干涉法得到了很快的发展,可以获得面内或离面位移,错位散斑干涉法则可获得位移梯度场。本文建议将光弹性透明模型置于双光束散斑干涉光路中,通过两次曝光法可以获得模型的应力条纹图案。但和全息光弹性法相比,只要选择合适的漫反射器,用散斑光弹干涉法可以获得不受等差线干扰的、单纯的等和线条纹图。同样的理由,也可以获得三维应力模型冻结切片的等和线条纹图。更有意义的是采用双光片散光穿透模型的散斑光弹性干涉法将有可能获得整体三维应力模型内部的绝对光程应力条纹图,这将为三维应力分析提供一种新的实验方法。     

用直接散斑技术测量复合材料试件的面内位移

直接散斑法用来测量带中心圆孔复合材料条状试件在拉伸载荷作用下的面内位移分布,采用镜面移植技术,提高复合材料试件表面的反射性能,从而得到高质量的散斑干涉干板,在分析散斑干涉干板时,由于得到的全场位移分布条纹频率的可调性,使此方法测量范围很宽,由弹性应变到塑性应变,直接散斑法测量的结果与云纹法得到的结果相符合。     

红宝石脉冲激光动态光力学方法研究与进展

本文提出了瞬态图像采集技术和电磁脉冲加载装置。应用红宝石脉冲激光光源,介绍了动态全息光弹性、动态散斑干涉、动态云纹干涉、水下爆炸全息干涉、动态电子散斑干涉和动态数字散斑相关等多种方法的测试原理和测试技术。为动态位移场、应变场和应力场的定量分析提供了广泛的应用前景。     

Preface: Current research progress on mechanics of high speed rail

The construction and operation of high-speed rail（HSR）grid within the past two decades in China,in terms of the scale,may be possibly comparable to any national-wide construction in the history of China,even the Great Wall.By counting railways with commercial train service at the speed of200 km/h,China has the world’s longest HSR network with over 19 369.8 km of track in service today and this number     

ACTA MECHANICA SINICA 2014 ANNUAL SUBJECT INDEX

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人造地震动合成中的位移误差分析

三角函数级数法是合成人工地震动常用算法之一,但是通过对加速度积分求取位移时,却存在与零线漂移相类似的位移漂移现象。     

Hermitian space-time finite elements for estuarine mass transport

Space-time finite element solutions of the convection–dispersion equation using higher-order nodal continuity and Hermitian polynomial shape functions are described. Five separate elements ranging from a complete linear element with C^0,0 nodal continuity to a complete first-order Hermitian element with C^1,1 nodal continuity are subjected to detailed analysis. Wave deformation analyses identify the source of leading or trailing edge oscillations, trailing edge oscillations being the major source of difficulty. These observations are confirmed by numerical experiments which further demonstrate the potential of higher-order nodal continuity. The performance of the complete first-order Hermitian element is quite satisfactory and measurably superior to the linear element.     

Rainwater rivulets on a cable subject to windFilets d'eau de pluie sur un câble soumis au vent

Rainwater rivulets appear on inclined cables of cable-stayed bridges when wind and rain occur simultaneously. In a restricted range of parameters this is known to cause vibrations of high amplitudes on the cable. The mechanism underlying this effect is still under debate but the role of rainwater rivulets is certain. We use a standard lubrication model to analyse the dynamics of a water film on a cylinder under the effect of gravity and wind load. A simple criterion is then proposed for the appearance and position of rivulets, where the Froude number is the control parameter. Experiments with several geometries of cylinder covered with water in a wind tunnel show the evolution of the rivulets with the Froude number. Comparison of the prediction by the model with these experimental data shows that the main mechanism of rivulet formation and positioning is captured. To cite this article: C. Lemaitre et al., C. R. Mecanique 334 (2006).     

Cristallisation par onde acoustique : le cas de l'héliumCrystallization by acoustic waves: the case of helium

We establish a theoretical model to explain the nucleation of a crystal of helium by an acoustic over-pressure. We explain the interfacial laws for this ultra-fast cristallization, close to the sound speed. Assuming spherical symmetry and taking into account the experimental data, we recover the dynamics of the growth and melting during an over-pressure impulse. To cite this article: M. Ben Amar et al., C. R. Mecanique 331 (2003).     

Structure initiale et propriétés de liquéfaction statique d'un sableInitial structure and static liquefaction properties of sand.

Based on the use of two different preparation procedures for reconstituting triaxial samples of sand, i.e. wet tamping and dry pluviation, significant differences in associated mechanical behaviour are observed on a reference sand with respect to the phenomenon of ‘static’ liquefaction. Wet tamping favours the initiation of liquefaction instability, whereas dry pluviation favours a more stable behaviour, less susceptible to liquefaction. Microscopic observation of corresponding sand specimens allows us to identify two well differentiated structures, i.e., for wet tamping, an irregular structure with predominance of aggregates (aggregated grains) and macropores, very contractant and unstable and, for dry pluviation, a more regular structure, without macropores, more dilatant and more stable. These observations show the importance of further characterization, based on the introduction of appropriate parameters, of the initial structure of sandy materials, strongly dependant upon their mode of formation (natural or artificial). To cite this article: N. Benahmed et al., C. R. Mecanique 332 (2004).     

INFORMATION FOR CONTRIBUTORS

Contributions： The Journal, Acta Mechanica Solida Sinica, is pleased to receive papers from engineers and scientists working in various aspects of solid mechanics. All contributions are subject to critical review prior to acceptance and publication.     

The 7th International Conference on Fluid Mechanics May 24-27,2015,Qingdao,China

正http://www.icfm7.org First Announcement and Call for PapersThe objective of International Conference on Fluid Mechanics(ICFM)is to provide a forum for researchers to exchange new ideas and recent advances in the fields of theoretical,experimental,computational Fluid Mechanics as well as interdisciplinary subjects.It was successfully convened by the Chinese Society of Theoretical and Applied Mechanics(CSTAM)in Beijing(1987,