一种孔中心距检测装置的设计

分析了孔中心距的尺寸特点,根据原有的孔中心距检测装置在测量中出现的问题,提出了新的孔中心距检测装置的设计方案,深入研究了孔中心距误差的测量原理,对孔中心距检测装置的结构进行了详细的设计,并且详细地描述了孔中心距检测装置的操作方法.所设计的孔中心距检测装置结构合理、操作方便,能快速准确地测出孔中心距的尺寸误差,提高了孔中心距尺寸误差的测量速度,改善了孔中心距尺寸误差的测量效率.     

基于视频桥墩防撞预警系统的软件设计

通过分析摄像机传回的视频图像,实现对桥墩防撞的预警。用摄像机获取当前江面图像,利用图像处理技术,识别过往船舶;通过摄像机测距技术,测量船舶与桥墩的相对位置,起到预警作用。     

电磁炮教具的制作与研究

根据"电生磁"和"磁生电"原理,能够制作出可实现发射和拦截的电磁炮装置。电磁炮涉及电磁感应、楞次定律等知识,教学适应性强,其发射板块和拦截板块均可作为教师讲解电磁之间相互作用关系的演示教具。     

一种桥梁防撞系统中的虚拟航道构建与船舶偏航检测方法

提出一种桥梁防撞系统中的虚拟航道构建与船舶偏航检测方法。首先在桥梁通航孔安装摄像机,采集航道图像视频信息,然后对采集的视频信息进行处理,最后在视频图像上显示出虚拟航道,通过计算船舶到虚拟航道的距离判断轮船是否偏航。对有航标和没有航标情况用不同的方法构建虚拟航道,对不同的河道地形构建出适应实际地形的直线型、C型和S型虚拟航道,能够准确绕开障碍物,保证船舶航行安全。实验表明该方法具有较高的正确率,对提高桥梁和船舶航行安全具有重要意义。     

铁路特大桥桥墩分段拆除爆破

对于环境相对复杂的钢筋混凝土桥墩进行拆除,采用逐层浅孔爆破技术,通过精心设计爆破方案的最小抵抗线、炮孔间距、炮孔排距、炮孔深度、爆破单位体积用药量和单孔装药量等参数;合理布置炮孔位置及装药结构;辅于严格的钻爆施工要求和周密的防护措施,定能在保障附近构造物及设施安全的前提下完成桥墩拆除,取得理想的爆破效果。     

广东坭洲头航道改线工程通航风险研究

航道改线是一个复杂的工程,改线后航道通航是否安全直接影响着船舶的通航安全和沿岸港口的可持续发展。本文通过对广东坭洲头航道改线工程通航风险评价的研究,编写了基于灰色模糊理论和集值统计法的风险评价软件,通过实例分析,阐述软件的工程实际应用价值,同时也进一步验证了软件的适用性和可行性。     

基于知识的监控系统设计

为了避免江河湖面上来往船只可能造成对桥墩的撞击,设计了一种基于知识的桥墩防撞智能化的系统.在桥墩设防区域的江河湖面上设置一定的监视区,一旦来往船只进入设防区域,系统能给出相应的警示报警和处理.     

渗透固结装置的研制及在实践教学中的应用

土的固结过程与渗透性质关系密切,但传统的固结仪不能进行渗透试验.该文研制了一种渗透固结装置,既能进行固结试验和渗透试验,又能测量固结过程中的孔压.装置构造简单,操作便捷,密封性能好,可自动记录孔压、时间等参数.该装置应用于研究生的土工试验教学,促进了土力学理论与实践教学的融合,不仅加深了学生对理论知识的理解,提高了学生...     

闻名中外的卢沟桥

北京有句歇后语:"卢沟桥的狮子——数不清。"——《卢沟桥的狮子》卢沟桥始建于金朝大定二十九年(1189年),康熙三十七年(1698年)重建。全长266.5米,宽7.5米,最宽处可达9.3米。有桥墩十座,共11孔,整个桥体都是石结构,关键部位均有银锭铁榫连接,为华北最长的古代石桥。而最有特色的,则是桥墩的造法。墩下     

振荡水柱装置波浪水槽试验中用于模拟非线性能量俘获系统的孔口特性(英文)

目的:在振荡水柱装置研究中,通常通过不同的孔口几何特征来改变能量俘获系统的特性,但其具体流动特性却鲜有报道。本文探讨孔口几何特征(形状、尺寸和开孔率等)对流动特性的影响机制,理解影响能量俘获系统特性的关键因素,研究其对振荡水柱装置水动力特性和波能提取的影响规律,并评估波能提取性能指标的有效性。创新点:1.提出了两点测量法来重构振荡水柱腔室内液面;2.建立了孔口流动特性与孔口几何特征的关系式;3.提出了仅测量腔室内气压即可获得波能提取功率的方法;4.该方法可扩展至非二维矩形腔室及斜向波。方法:1.采用不同尺寸狭缝孔和圆形孔来模拟非线性能量俘获系统;2.通过一系列波浪水槽试验,对振荡水柱装置的水动力特性及波能的提取展开研究;3.采用二次损耗系数和收缩系数来描述孔口往复流动特性,并构建其与孔口几何特征的关系;4.通过两点测量法获取振荡水柱腔室内的准确信息;5.评估压力波动系数和液面放大系数作为振荡水柱装置波能提取性能指标的有效性。结论:1.两点测量法能够重建二维矩形振荡水柱腔室内液面的瞬时空间分布,消除了单点法的测量偏差;2.孔口相对厚度及振荡气流对可被视为薄壁的圆形孔的影响可以忽略不计,但对不能视为薄壁的狭缝孔的影响显著;3.本文提出的二次损耗系数经验公式可用于(1)通过孔口几何尺寸设计其流动特性和(2)通过仅测量腔室内气压来计算波能提取功率;4.用作振荡水柱装置的波能提取性能指标时,压力波动系数比液面放大系数更为可靠。     

Simulation and Reasonable Design of Bridge Steel Fenders to Reduce Ship Impacts

Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.     

Simulation and Reasonable Design of Bridge Steel Fenders to Reduce Ship Impacts

Steel fenders are increasingly used for ship-impact resistance structures in the design of navigable bridges. As an important approach to investigating this anti-impact structure effectiveness to reduce influences of vessel impact, simulation analyses are still not perfect yet. So this paper is intended to discuss several issues related to ship collision simulations, including steel constitutive relationship, connections between steel box and pile cap, contacts definition and friction consideration, and the determination of impact waterlines and angles. Consequently based on two examples of ship-steel fender-bridge structure systems, some conclusions about effectiveness and design of fenders to reduce ship impact are drawn.     

用倾斜气轨系统与Spss测定重力加速度

用垫块调整气轨的倾斜角,使滑行器在自身重力作用下沿气轨表面直接做功,使用智能计时系统精准测出滑块在气轨斜面定点位置的速度。由测量原理及不确定度分析,对照测量数据,引入Spss的曲线估计功能分析得到速长综合量与垫块高度的定标曲线,并验证出速长综合量与垫块高度存在线性关系,由此标定出重力加速度,并用置信概率为95%的不确定度对其进行了合理的分析和评定,得到更加合理的实验结果。     

Aerodynamic stability of cable-stayed bridges under erection

INTRODUCTION Long-span cable-stayed bridges under service andparticular construction conditions are very susceptibleto wind action due to their great flexibility, so thewind stability (aerodynamic stability or flutter stabil-ity) is becoming a major concern in the design andconstruction phrases. As compared with the servicecondition, although the period of erection is not toolong, the structural stiffness of cable-stayed bridgesunder erection is greatly reduced, and consequentlythey be…     

Calculation method of ship collision force on bridge using artificial neural network

Ship collision on bridge is a dynamic process featured by high nonlinearity and instantaneity. Calculating ship-bridge collision force typically involves either the use of design-specification-stipulated equivalent static load, or the use of finite element method （FEM） which is more time-consuming and requires supercomputing resources. In this paper, we proposed an alternative approach that combines FEM with artificial neural network （ANN）. The radial basis function neural network （RBFNN） employed for calculating the impact force in consideration of ship-bridge collision mechanics. With ship velocity and mass as the input vectors and ship collision force as the output vector, the neural networks for different network parameters are trained by the learning samples obtained from finite element simulation results. The error analyses of the learning and testing samples show that the proposed RBFNN is accurate enough to calculate ship-bridge collision force. The input-output relationship obtained by the RBFNN is essentially consistent with the typical empirical formulae. Finally, a special toolbox is developed for calculation effi- ciency in application using MATLAB software.     

Dynamic Simulation on Collision Between Ship and Offshore Wind Turbine简

By using ABAQUS/Explicit, the dynamic process of an offshore wind turbine（OWT） stricken by a ship of 5000DWT in the front direction is simulated. The OWT is located on a large-scale prestressing bucket foundation constructed by an integrated installation technique. According to the simulation results, under the ship collision, a cer-tain range of plastic zone appears within a local area of arc transition structure of the bucket foundation, and the con-crete plastic zone is seriously damaged. As the stress level of OWT tower is relatively low, the OWT tower is less af-fected. A great inertial force is generated at the top of the OWT tower as the mass of nacelle and blades is up to 400 t. The displacement of the tower is in the opposite direction of the ship collision at the end of 1 s under the action of iner-tial force. There is only a minor damage in the ship bow. Most of the kinetic energy is transformed into the plastic dissipation and absorbed by the arc transition structure of bucket foundation.     

船舶主机烟气余热海水淡化装置设计

海水淡化装置是船舶上重要的设备,是船舶设备正常运行和船上人员日常生活的基本保障,其性能好坏直接影响船舶的营运情况。在分析船舶余热和现有海水淡化技术的基础上,提出了利用船舶烟气余热、冷却水余热作为海水淡化装置热源进行海水淡化新型装置设计的新思路,为船舶能量利用及海水淡化装置设计提供参考。     

钢管混凝土格构式梁桥设计参数抗震研究

以三跨一联钢管混凝土格构式高墩连续梁桥为研究对象,探讨了梁墩刚度比、缀管布置形式和有无减隔震装置设计参数对格构墩地震响应（墩底轴力、墩底弯矩和墩顶位移）的影响规律。研究结果表明:随着梁墩刚度比值的增大,桥墩的地震响应值先急剧下降之后逐渐趋于平缓减小;缀管布置形式参数对格构墩的弯矩响应值影响较为敏感,而轴力和位移值受其影响较小;减隔震装置对该类桥梁的隔震效果显著,隔震率随梁墩刚度比值的增大而减小。设防烈度等级越高,轴力隔震效果越明显,弯矩和位移的隔震率受设防烈度等级影响较小。该研究可为同类桥梁抗震概念设计提     

Numerical Simulations of Pile Supported Protective System Subjected to Ship Impact

The head-on collision process between ship and concrete pile supported protective system is simulated by software LS-DYNA. The influences of pile non-linearity and soil non-linearity on impact force, ship crush depth and the cap displacement of pile supported protective system are discussed. It's shown that for both severe impact case and non-severe impact case, the non-linearity of pile material influence the impact force history, ship crush depth. The non-linearity of pile material and soil has remarkable influence on the cap displacement especially for severe impact case. These issues should not be ignored in the analysis of pile supported protective system subjected to ship impact.     

Aerodynamic stability of cable-stayed-suspension hybrid bridges

INTRODUCTION The cable-stayed-suspension (CSS) hybridbridge is developed from the traditional cable-stayedbridge and suspension bridge, and has some advan-tages of the two bridge types described as follows: 1. As compared with the suspension bridge of thesame span length, the suspension portion is greatlyshortened, so the tensional forces in the main cablesare greatly decreased, which helps to decrease theconstruction costs of the main cables and the massiveanchors, and the difficulty of…