某既有隧道测量及限界分析与研究

通过对7381既有隧道测量及限界分析,初步确定了哈尔滨市轨道交通一期工程的车辆限界、线路技术参数等,对地铁建设节约投资、发挥更大的效益以及可行性研究和设计提供参考。

哈尔滨市轨道交通一期工程7381既有隧道测量及限界分析研究

通过对7381既有隧道测量及限界分析与研究,可以初步确定哈尔滨市轨道交通一期工程的车辆选型、线路技术标准等,对地铁建设节约投资、发挥更大的效益以及可行性研究和设计提供参考。

基于三维激光扫描技术的地下隧道工程限界分析与应用研究

地铁是典型地下隧道工程,而作为地铁建设过程中必不可少的一环,限界测量分析是轨道铺设和设备安装的必备条件。限界分析往往需要提供隧道断面上特定位置点的相关数据,传统全站仪单点测量方式难以满足,而借助三维激光扫描技术,则可以获得整个隧道的空间形态,提取任意位置的几何数据;本文以RTC360扫描仪获取的青岛地铁1号线高精度点云数据为基础,通过对点云数据拼接、绝对定向、去噪、裁切和抽稀等预处理,利用自主研发的隧道点云处理软件自动提取任意里程指定位置的限界数据并一键报表生产。相比全站仪测量方式,基于三维激光点云数据的地铁限界分析方法可以准确获取特定位置的数据,极大地提高内外业作业效率。

地铁屏蔽门限界的分析及措施

通过对屏蔽门系统限界的分析,阐述在系统设计中采取有效的处理措施来避免屏蔽门与列车间隙过宽造成的安全隐患。说明在屏蔽门系统的设计阶段,系统的结构设计不但应满足不侵入车辆限界,而且还应采取多种设计方案组合,最大限度地减小屏蔽门门体与列车之间的间隙,并对该空隙实施监测,以消除因屏蔽门与列车之间的间隙过宽而可能存在的安全隐患。

基于三维激光点云的地铁限界测量分析与应用研究

作为地铁建设过程中必不可少的一环,限界测量分析是轨道铺设和设备安装的必备条件。限界分析往往需要提供隧道断面上特定位置点的相关数据,传统全站仪单点测量方式难以满足,而借助三维激光扫描技术,则可以获得整个隧道的空间形态,提取任意位置的几何数据。本文以RTC360扫描仪获取的青岛地铁1号线高精度点云数据为基础,通过对点云数据拼接、绝对定向、去噪、裁切和抽稀等预处理,利用自主研发的隧道点云处理软件自动提取任意里程指定位置的限界数据并一键报表生成。相比全站仪测量方式,基于三维激光点云数据的地铁限界分析方法可以准确获取特定位置的数据,极大地提高内外业作业效率。

分析限界算法在企业动力系统优化中的应用

优化决策对于任何一个企业动力系统来说都是必要的。炼油厂蒸汽供应系统的优化问题是一个复杂的混合0-1整数线性规划问题:Z=CX,将Z转换为系列辅助约束关系(之和)后,可直接运用分支限界算法(结合反向搜索法)进行优化并分析,得到全局最优决策,这种方法对其他企业动力系统的优化同样适用。

基于移动三维激光扫描仪的地铁限界测量分析

传统架站式三维激光扫描技术在地铁限界测量中,存在采集数据繁琐,点云处理难度高等问题,同时现有的限界分析软件测量节点稀少。本文针对以上问题,利用移动式三维激光扫描仪,对昆明地铁某段隧道进行了相对测量。点云数据通过处理,导入专业的限界测量分析软件,完成净空差值测量,测量结果显示,测量区间未有任何超限病害,并快速生成图文一体检测报告,验证了本文提出的地铁限界测量技术,能够提供高效、准确、便利的服务。

基于激光检测技术的地铁限界检测研究

地铁限界检测的常规方式是通过定做安装在龙门架上的限界规进行,该测量方式存在定制周期长、制作安装误差大、试验报告不精确等问题,同时对存在超限的车体可能会造成剐蹭,导致车辆返工。针对以上问题,采用三维激光扫描装置,采集车辆的点云数据,导入专业的限界测量分析软件,完成净空差值测量。测量结果显示:激光限界检测的方式可满足高精度的限界试验要求,同时,结合软件可快速生成图文一体检测报告,满足批量化的地铁车辆的限界检测要求。

铁路车辆激光限界校准方法及不确定度浅析

目前在高铁、城轨及电力机车的限界检测中,静态限界模板的检测方法在检测效率、精度及可追溯性等方面已日渐难满足日益增长的检测需求,一种基于结构光视觉检测技术由激光3D相机搭建的检测系统(下文以三维激光扫描限界检测技术简称)正逐步替代静态限界模板的检测方法,走上轨道交通车辆外形轮廓的检测舞台。本文以本公司采用的激光限界检测系统为例,通过分析三维激光扫描限界检测技术原理及校准流程,确定测量系统不确定度来源并进行不确定度评定。验证了三维激光扫描限界检测技术可靠性并指出减少不确定度的方向。

基于车载激光扫描点云的铁路隧道横断面提取

针对三维激光扫描技术在铁路隧道限界分析和收敛分析等应用中的关键的点云横断面的快速提取问题,提出了适应马蹄形铁路隧道的断面快速提取方法。该方法利用铁路钢轨来确定隧道横断面的方向,并利用RANSAC方法完成隧道断面点云的分类,完成铁路隧道边墙断面的提取。通过实际铁路隧道的车载Lidar点云对提出的方法进行试验。实验结果表明:该方法能够快速完成铁路隧道横断面快速提取,并验证了所提取的断面在隧道限界分析和收敛分析中的实用性。

基于LiDAR点云的铁路隧道横断面提取

针对三维激光扫描技术在铁路隧道限界分析和收敛分析等应用中关键的点云横断面的快速提取问题,本文提出了适应马蹄形铁路隧道的断面快速提取方法。该方法利用铁路钢轨来确定隧道横断面的方向,并利用RANSAC方法完成隧道断面点云的分类,并完成铁路隧道边墙断面的提取。通过实际铁路隧道的Lidar点云对提出的方法进行试验。实验结果表明,该方法能够快速完成铁路隧道横断面提取,并验证了所提取的断面在隧道限界分析和收敛分析中的实用性。

Modeling Technology in Finite Element Analysis of Electrostatic Proximity Fuze Problem

In order to analyze the electrostatic field concerned with electrostatic proximity fuze problem using the available finite analysis software package, the technology to model the problem with a scale reduction object and boundary was presented. The boundary is determined by the maximum distance the sensor can detect. The object model is obtained by multiplying the terms in Poisson's equation with a scale reduction factor and the real value can be reconstructed with the same reverse process after software calculation. Using the finite element analysis program, the simulation value is close to the theoretical value with a little error. The boundary determination and scale reduction method is suitable to modeling the irregular electrostatic field around air targets, such as airplane, missile and so on, which is based on commonly used personal computer (PC). The technology reduces the calculation and storage cost greatly.

三维激光扫描技术在隧道断面检测中的应用研究

在公路隧道建设过程中,施工过程往往会面临围岩差、施工不规范、衬砌混凝土质量不稳定等因素,质量管理难度较大,特别是隧道断面的净空控制,超欠挖情况将直接影响隧道工程建设质量,传统测量方法中全站仪、断面仪受隧道控制点精度、测量方法及隧道洞内光线环境因素的影响,效率低下,效果较差。三维激光扫描技术作为革命性的高新技术,可以快速、高效获得所测物体的三维空间信息数据,构建物体真实三维场景,在工程建设领域已得到广泛应用。探讨将三维激光扫描技术应用于隧道断面限界检测中,通过断面点云数据采集,经过后期软件处理,及时掌握隧道在施工过程中是否存在侵限情况,为隧道施工过程管控提供数据支撑。

Response mechanism for widened pavement structure subjected to ground differential settlement

By the use of a large-scale ground differential settlement simulator, a full-size model test is performed to study the strain response and the deformation behavior of both the wearing course of asphalt cement and the base course of cement-stabilized gravel. Moreover, with the differential settlement at the bottom of the pavement structure as the constraint condition, a plane finite element model is established, which is used to study the stress variation of different pavement layers in response to the differential settlement of varying magnitudes. It shows that, under the effects of the ground differential settlement, the wearing course is subjected to the tensile stress while the base course to the compressive stress and the maximum additional tensile stress and compressive stress occur in the area of 1 m from the splicing joint between the new and the old subgrade. Plastic deformation develops in both layers when the ground differential settlement reaches 14 cm. When the differential settlement at the bottom of the pavement goes up to 1 cm, the maximum additional stress in the surface of the base course will reach 0. 28 MPa, which surpasses 0.276 MPa that is specified in the current specifications as the maximum splitting tensile strength for cement-stabilized base material.

Temperature Characteristics of Bilayer Thin-Film Devices Under Organic Interface Limited Current Conduction

Temperature characteristics are important for the performance of organic thin film devices. On the basis of the hopping theory of Miller-Abrahams,an analytical model of charge transport for bilayer organic devices under the organicorganic interface limited current conduction is developed. The dependence of current, field,and carrier distribution in bilayer organic devices with the structure of ＂injection electrode/Layer Ⅰ/Layer Ⅱ/collection electrode＂ on temperature are numerically analyzed. We conclude that, for a given applied voltage, when temperature is raised, the voltage of LayerⅠ will increase,and the field will be higher. Meanwhile, the voltage of Layer Ⅲ will decrease, the field will become weaker accordingly,and the current of the device will increase.

推出铁路基础设施激光扫描系统

美国天宝(Trimble)公司推出了GEDO GX50运动激光扫描系统,该系统旨在通过其GEDO轨道测量技术支持限界分析和资产数据采集。GEDO GX50系统配备了美国天宝公司设计的用于高精度数据采集的新型轮廓激光器。激光器配备了一个或两个激光扫描头,可根据使用要求进行调整。当需要更高的点密度或需要更快的列车移动时,模块化设计允许添加第二个激光扫描仪。

Distribution of stress and strain between adjacent particles in particulate reinforced metal matrix composites

The distribution of stress and strain between adjacent particles in particulate reinforced metal matrix composites wasinvestigated using cohesive zone models. It is found that the strain of the composite is concentrated in the matrix, and there is aregion with higher strain along the loading path, which can promote the formation of a void near the particles pole. The stress andstrain in matrix near the particles gradually decrease with the increase of the distance between particles. And it is calculated that thereis a critical distance within which the stress and strain fields of the neighboring particles can influence with each other. This criticaldistance increases with the increase of particle size. It is also found that the angle between the tensile direction and the center line ofparticles plays an important role in the stress and strain distribution. The model with the angle of 0° has the greatest influence on thedistribution of stress and strain in the matrix, while the model with the angle of 45° has the least influence on the distribution of stressand strain in the matrix.

Structure and behavior of floor system of two super high-speed railway Changjiang composite bridges

Wuhan Tianxingzhou Changjiang (WTC) Bridge and Nanjing Dashengguan Changjiang (NDC) Bridge are two super high-speed railway 3-trusses composite bridges. This is the first time of using three trusses in such large bridges in the world. These two types of railway floor systems of the two bridges have never been used in China before. The problem how to conform the deformations and stress levels of the railway floor system of WTC Bridge was studied. After finite element analysis and comparison,the plan of arranging one expansion stringer every two panels in railway floor system were proposed and good effect was obtained. Because of the application of three trusses,the allocation of the loads acted on the deck in three trusses is different and varies in different places of NDC Bridge. This problem was studied by model experiment and 3D finite element analysis. The results of 3D FEM analysis coincide with the model test results. The allocation rule of the loads acting on the deck in three trusses was presented. Because of the application of monolithic decks,the stiffness and structural integrity of NDC Bridge are high.

Design of an Experimental Set‑up Concerning Interfacial Stress to Promote Measurement Accuracy of Adhesive Shear Strength Between Ice and Substrate

Accumulation of ice on airfoils and engines seriously endangers the safety of the fight.The accurate measurement of adhesion strength at the ice-substrate interface plays a vital role in the design of anti/de-icing systems.In this pursuit,the present study envisages the evaluation of the stress at the icesubstrate interface to guide the design of experimental set-ups and improve the measurement accuracy of shear strength using the finite element analysis(FEA)method.By considering such factors as the peeling stress,maximum von-mises stress and uniformity of stress,the height and radius of ice and the loading height are investigated.Based on the simulation results,appropriate parameters are selected for the experimental validation.Simulation results show that the peeling stress is decreased by reducing the loading height and increasing the height of ice.Higher ice,increasing loading height and smaller ice radius are found to be beneficial for the uniformity of stress.To avoid cracks or ice-breaking,it is imperative that the ice should be of a small radius and greater height.Parameters including the ice height of 25 mm,radius of 20 mm,and loading height of 9 mm are adopted in the experiment.The results of FEA and the experimental validation can significantly enhance the measurement accuracy of shear strength.

An Upper Bound for the Number of Normalized Latin Square

In this note, the author find an upper bound formula for the number of the p × p normalized Latin Square,the first row and column of which are both standard order 1, 2,…p.