The development of studying flexible pipe bend reinforced by Kevlar fibers

The flexible pipe bend can not only reduce the structural vibration and fluid noise in pipeline, but also realize the flexible connection of a horizontal line and a vertical line and compensate the displacement of three dimensions produced by the shock or vibration of pipeline in the special situations. Up to now, little attention has been paid to study the flexible pipe bend applied in the pipeline of medium or high pressure, because no appropriate framework materials can be used to reinforce it which must endure the burst pressure higher than 10 MPa. The investigation shows that it is possible to produce the flexible pipe bend of medium or high pressure if such fibers with high performance as Kevlar fibers are used to be its reinforced materials. However, its structural designing theory, manufacturing technology and measuring techniques aren‘t yet perfect and systematic, which leads to the instability of the performance of products. Furthermore, few references about its research can be seen. Therefore, it is necessary to systematically and thoroughly develop the structural designing theory, manufacture technology and measuring techniques of flexible pipe bend.     

船舶进出港规则对沿海进口散货港区航道通过能力的影响*

沿海散货船舶大型化,对配套的航道条件提出更高的要求,合理的船舶进出港规则对发挥航道通过能力起到重要的作用。利用计算机仿真技术,通过构建沿海进口散货港区船舶航行作业系统仿真模型,研究先来先服务规则、大船优先服务规则和船舶成簇进出港规则对航道通过能力的影响。结果表明:3种规则下,航道通过能力与服务水平均呈指数分布关系;先来先服务规则和大船优先服务规则对航道通过能力的影响基本相同;而对于港口规模大、航道通航历时长的港区成簇进出港规则要比前两种规则对应的航道通过能力高。     

Ship hull plate processing surface fairing with constraints based on B-spline

The problem of ship hull plate processing surface fairing with constraints based on B-spline is solved in this paper. The algorithm for B-spline curve fairing with constraints is one of the most common methods in plane curve fairing. The algorithm can be applied to global and local curve fairing. It can constrain the perturbation range of the control points and the shape variation of the curve, and get a better fairing result in plane curves. In this paper, a new fairing algorithm with constraints for curves and surfaces in space is presented. Then this method is applied to the experiments of ship hull plate processing surface. Finally numerical results are obtained to show the efficiency of this method.     

桥梁方沉井浮运阻力研究

运用计算流体软件FLUENT对方形钢沉井浮运时受到的水阻力进行数值计算,得到了不同流速不同吃水工况下沉井外壁和沉井整体的水阻力,并将FLUENT计算结果与经验公式估算结果比较分析,验证了经验公式中只规定外壁为档水面积是不合理的.在实际浮运中沉井内壁也受到了较大的水阻力,并且不可忽略.依据FLUENT数值结果对经验公式进行修正,修正后的经验公式考虑了内壁受到的水阻力,可更准确地估算方形沉井浮运时的水阻力.修正后的经验公式可为工.--f~工程实际应用提供方便.     

城市轨道交通振动与噪声

随着经济的发展 ,城市轨道交通的振动和噪声问题越来越引起人们的重视。叙述了轨道结构振动的产生原因及环境振动的评价指标 ,分析了铁路噪声的组成及对环境噪声的评价标准。通过对国内外资料的分析 ,认为轮轨噪声是城市轨道交通噪声的主要组成部分 ,要对轨道交通减振降噪 ,降低轨道结构的振动是关键。最后提出对轨道交通减振降噪的一些建议。     

混凝土箱梁温度分布及其影响分析

结合某连续箱梁桥悬臂施工控制,进行了箱梁混凝土温度分布的现场观测,观测结果表明,太阳辐射作用下,混凝土箱梁沿高度的温度分布为非线性分布。通过对温度实测数据的分析,提出了公路桥梁混凝土箱梁温差计算建议模式,在此基础上,对混凝土箱梁的温度应力、施工过程中的温度变形进行了分析研究。     

A new model for soil consolidation based on microstructure

This paper introduces a new means to predict consolidation deformation of soil from its microstructure. Based on a kind of pore-size distribution density function, a fractal model for soil consolidation is established. Through this model, the relation between macroscopic deformation and microcosmic pore property of soil is founded. In order to justify this proposed model for soil consolidation, consolidation experiments of soft clay are performed. Afterward, the microstructure of soft clay unconsolidated and consolidated under every pressure is studied by a scanning electron microscope (SEM). The results show that the proposed model for soil consolidation is valid in predicting consolidation deformation.     

Numerical simulation of non-destructive testing of stainless steel composites plate by infrared thermography

The non-destructive testing (NDT) of debonding in stainless steel composites plate (SSCP) is performed by infrared thermography, finite element analysis (FEA) software ANSYS is taken as the simulative tool, and 2D simulative model has been set up to investigate effect of the thickness of coating and/or substrate on the detectibility of debonging in SSCPs. Two parameters, namely the maximum defect temperature difference and defect appearing index, are defined to evaluate the detectivity of defects, and their computational methods and formulas are given respectively. The preliminary changing tendency of the maximum defect temperature difference and defect appearing index with the thickness of coating and/or substrate is found by numerical simulation.     

城市生活垃圾收运路线优化模型及算法研究

针对城市垃圾收运的现状,以垃圾收运的约束条件建立了单目标的垃圾收运路线优化模型,进而提出了相应的遗传算法,最后通过案例验证表明遗传算法求解垃圾收运问题能得出良好的近似解并具有较高的收敛速度,由此说明遗传算法在求解收运路线问题上具有较高的效率和较强的可行性。     

基于通信的列车控制(CBTC)系统中轨旁控制子系统一体化研究

分析了国内外CBTC(基于通信的列车控制)系统的结构特点.针对典型CBTC系统存在的问题,着重分析了CBI(计算机联锁)和ZC(区域控制器)均采用同一硬件和同一软件的轨旁控制子系统一体化方案,给出了该方案下轨旁控制子系统为列车计算行车许可的方法.最后对一体化的CBTC系统与典型CBTC系统下开放信号机、关闭信号机、人工...