剪切散斑干涉技术的研究

剪切散斑干涉技术是利用相干光照射在粗糙的物体表面,在空间所形成的散斑,实现物体表面位移和变形检测。它具有可以全场测量,光路简单,调节方便,对环境要求低等特点。主要讨论基于迈克耳孙的剪切散斑干涉术的原理及位移导数与条纹之间的关系。通过相关实验证明剪切散斑干涉技术在物体离面位移检测中的准确性和有效性。     

电子散斑干涉技术在振动测试中的应用

电子散斑干涉技术是在激光、视频、电子及数字图像处理等基础上发展起来的现代光测技术,具有全场、非接触和灵敏度高等优点,近年来得到了迅速发展.本文介绍了电子散斑干涉法的基本原理和国内外在振动测试领域的最新研究应用进展,分析了尚待解决的一些问题,探讨了未来的发展趋势.     

散斑及其应用探究

散斑效应是信息光学的重要组成部分,现在,散斑效应的应用已经渗透到很多领域,主要通过对散斑效应的应用作初步的探讨,着重介绍散斑摄影术和散斑干涉计量术。     

剪切电子散斑干涉术中消偏振效应的研究

就散射光的偏振性对剪切电子散斑干涉术中的影响进行了研究，文中给出了理论分析及实验结果，得出了消偏振效应不改变计量条纹调制度，但降低光能利用率的结论。     

白光频闪散斑干涉术的研究

在利用白光对振动物体进行测量时,由于白光的相干性较差,难以得到质量较好的图像,为了克服这一缺点,本文提出了一种用白光光源照明进行振动测量的新方法-白光频闪散斑干涉术.阐述了白光频闪散斑干涉术的基本原理,分析了提高图象质量的主要原因,采用了相干性较好的白光光源和合理的光路,使系统的时间相干性和空间相干性得到提高,从而提高了图像的质量.实验结果表明,该方法用于振动的测量,能给出物体在任一瞬时的振动信息,得到清晰的、高对比度的全场干涉条纹图,图像的质量得到大大提高.     

散斑检测技术及其应用

综述了散斑计量中的主要检测技术。主题包括散斑照相技术、散斑干涉技术、电子散斑干涉技术、数字散斑相关技术和时间序列散斑检测技术。介绍了散斑计量在科学和工程研究中的一些重要应用。     

电子错位散斑干涉系统中错位量的研究

电子错位散斑检测系统中,错位量对测量精度、灵敏度以及条纹对比度有很大影响。本文介绍了电子错位散斑干涉原理,研究了错位量与测量精度、灵敏度和条纹对比度之间的对应关系,并利用MATLAB模拟出不同错位量下干涉条纹图,将错位散斑模拟条纹图与理论分析有效结合,总结出选取错位量的方法,并将其应用于轮胎变形检测实验,取得了良好的实验效果。本文研究工作对无损检测中错位量定量选取具有实际指导意义。     

轮胎剪切散斑干涉包裹相位图缺陷识别方法

目前轮胎剪切散斑干涉缺陷识别技术主要依靠人工辅助识别,难以满足大批量工业生产检测的需要。该文提出基于剪切散斑图角点特征的轮胎缺陷识别方法,实现轮胎缺陷自动识别。首先通过对激光剪切散斑干涉包裹相位图缺陷特征、去噪方法等方面进行分析,并根据激光散斑干涉包裹相位图角点特征,提出基于角点特征的包裹相位图缺陷识别方法。实验结果表明:在两组包裹相位图缺陷识别实验中,该文方法对条纹质量较好、较差的包裹相位图,缺陷识别效果准确、定位精度高,该方法简单、高效,有助于提高轮胎缺陷检测速度与效率,可实现自动化轮胎缺陷检测。     

相移数字散斑干涉计量系统

本建立了一套相移激光数字散斑干涉自动测量系统,运用一系列的图象处理方法,实现了高精度的自动测量,显地提高了数字散斑干涉计量技术的可靠性、实用性及自动化程度。该计量系统被应用于变形、振动等参数的测量中,取得了较为理想的结果。     

用散斑干涉光谱分布检测瞬态温度

为了提高对瞬态温度检测的灵敏度,提出了基于散斑干涉条纹光谱分析的瞬态温度反演算法.系统利用散斑干涉形成干涉条纹,由于瞬态温度的变化会使材料应变,从而使散斑干涉条纹改变.被测表面形变前后获得的干涉条纹由面阵 CCD 采集,其对应的光谱密度分布函数也会发生相应的改变,即由散斑干涉条纹反演得到的中心波长振幅发生改变.通过对两次中心波长幅值的比值的检测和计算,即可获得被测的瞬态温度.在分析计算了瞬态温度变化与材料应变、材料应变与干涉条纹变化的函数关系的基础上,推导了瞬态温度变化与干涉条纹振幅及相位函数关系.实验采用660 nm 半导体激光器,SI6600型面阵 CCD 探测器,从获得的光谱分布函数中提取中心波长处幅值比值,通过计算和标定,最终温度检测精度可达到±2℃.相比传统的直接检测干涉条纹的变化量,由被测面形变量推导温度的方法精度提高了近一个数量级,其精度更高、检测均匀性更好、稳定性更好.     

规定非比例伸长应力σp0.2的图解测定法分析

对拉伸试验系统具有两个不同弹性系数情况下的夹头位移法和引伸计法所测规定非比例伸长应力σｐ０．２，做了分析，根据引伸计法及夹头位移法的精度要求，指出了夹头位移法的弊端和推广使用引伸计法的必要性以及引伸计法的发展方向。     

A free-front tracking algorithm for a control-volume-based Hele–Shaw method

With free surface flow problems the position of the free front at a particular time step needs to be predicted. When simulating the flow of hot molten polymer in injection moulds this position is essential for the prediction of the position of the weld lines on the final product. Weld lines are important in that they indicate positions of diminished strength and spoil the aesthetics of the product. A code using a finite volume approach on the thin gap Hele–Shaw flow equations to simulate the filling stage of the injection moulding process has been developed which requires a suitable algorithm for the free-front tracking. The Volume of Fluid (VOF) method was implemented in this study for the tracking of the free front. The discretization and various formulations of the VOF equation are presented as well as the results obtained. The impact on the existing equations is also investigated as well as the development of a packing routine that is used to eliminate the diffusive nature of the VOF equation. © 1998 John Wiley & Sons, Ltd.     

浅析我国工程造价的确定方法

本文对我国目前工程造价的确定的主要方法及存在的问题进行了研究。     

线加权余量法及其在正交异性板弯曲分析中的应用

利用有限差分法对控制方程和边界条件进行半离散化,使其定义在一些离散线上,然后采用加权余量法求解。这就是本文提出的线加权余量法,也可称之为有限差分-加权余量分维耦合法。文中以正交各向异性薄板弯曲平衡问题为例推导了有关具体算式,给出了数值算例,说明了本文方法的有效性。     

结构实体混凝土质量检验与评定的几点看法

结构实体混凝土的质量关系整个结构实体的安全,其检测、检验与评定备受相关责任方的关注。本文从加强实体混凝土质量现场检测的必要性、现场检测评定存在的有关问题等方面提出了几点看法,并提出了解决的这些问题的建议。     

浅谈我国工程造价的计价法

随着我国社会主义市场经济的发展,特别是加入WTO后,建设工程造价行业与国际惯例接轨势在必行。我国建筑企业要在市场中赢得项目,必须了解工程造价计价法及它们之间的区分,同时也是融入市场的前提。本文浅谈一下对我国工程造价计价法的理解。     

On the application of the method of difference potentials to linear elastic fracture mechanics

The Difference Potential Method (DPM) proved to be a very efficient tool for solving boundary value problems (BVPs) in the case of complex geometries. It allows BVPs to be reduced to a boundary equation without the knowledge of Green's functions. The method has been successfully used for solving very different problems related to the solution of partial differential equations. However, it has mostly been considered in regular (Lipschitz) domains. In the current paper, for the first time, the method has been applied to a problem of linear elastic fracture mechanics. This problem requires solving BVPs in domains containing cracks. For the first time, DPM technology has been combined with the finite element method. Singular enrichment functions, such as those used within the extended finite element formulations, are introduced into the system in order to improve the approximation of the crack tip singularity. Near-optimal convergence rates are achieved with the application of these enrichment functions. For the DPM, the reduction of the BVP to a boundary equation is based on generalised surface projections. The projection is fully determined by the clear trace. In the current paper, for the first time, the minimal clear trace for such problems has been numerically realised for a domain with a cut. Copyright © 2015 John Wiley & Sons, Ltd.     

Estimation of the Parameters of a Mixture of Exponential and Weibull Distributions with Progressive Censoring

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions using censored samples. Preliminary estimates obtained by graphical analysis are refined by the method of maximum likelihood. The efficiency of the method is confirmed by the results of a statistical modeling.     

Domain Type Kernel-Based Meshless Methods for Solving Wave Equations

Coupled with the Houbolt method, a third order finite difference time marching scheme, the method of approximate particular solutions (MAPS) has been applied to solve wave equations. Radial basis function has played an important role in the solution process of the MAPS. To show the effectiveness of the MAPS, we compare the results with the well known Kansa's method, timemarching method of fundamental solutions (TMMFS), and traditional finite element methods. To validate the effectiveness and easiness of the MAPS, four numerical examples which including regular, smooth irregular, and non-smooth domains are given.     

对石场梯段开采中钻孔积水的分析和处理方法的探讨

从爆破工作的实际出发，阐述了钻孔内积水对爆破工作造成的影响，分析了钻孔积水的成因及其特点，初步提出孔内和孔外处理钻孔内积水的方法，并对其适用性进行评价。