蛇口集装箱码头二期地基处理工程的总结和思考

结合施工过程中的各项监测数据及堆场使用2年后的沉降情况,介绍SCT2地基处理工程的设计、施工情况,以及施工中存在的引孔、边界处理等主要技术问题及其解决办法。     

Characteristics of a bubble jet near a vertical wall

A numerical model of a coupled bubble jet and wall was built on the assumption of potential flow and calculated by the boundary integral method. A three-dimensional computing program was then developed. Starting with the basic phenomenon of the interaction between a bubble and a wall, the dynamics of bubbles near rigid walls were studied systematically with the program. Calculated results agreed well with experimental results. The relationship between the Bjerknes effect of a wall and characteristic parameters was then studied and the calculated results of various cases were compared and discussed with the Blake criterion based on the Kelvin-impulse theory. Our analyses show that the angle of the jet＇s direction and the pressure on the rigid wall have a close relationship with collapse force and the bubble＇s characteristic parameters. From this, the application range of Blake criterion can be determined. This paper aims to provide a basis for future research on the dynamics of bubbles near a wall.     

低空气湿度对空调车厢热舒适性的影响

分析了轨道交通车辆车厢内空气湿度及温度变化时对PMV值的影响.还给出了PMV-PPD的计算结果,结果表示当车厢空气温度范围是16～20 ℃时,湿度的降低,使热舒适性差;21～25 ℃时对热舒适性影响不大,冬季一般控制在18 ℃左右,在不能提高车厢内温度的前提下,建议增加空气加湿设备以提高车厢内的热舒适性.     

山区高速公路沿线桥梁的总体规划及选型

百色至靖西高速公路是一条典型山区高速公路,具有桥隧比例高、地形地质复杂等特点,为在该线路上合理地布设桥梁,首先确定单工点桥梁的基本原则,再对布设桥梁遇到的一些特殊情况,如路线跨越较薄山脊的情况、地质条件好的"V"形山谷是否设桥、岩溶不良地质条件下桥跨选择、斜桥的布置以及同一施工标段内桥跨的统一等情况,充分综合分析了桥梁前、后的路线整体条件来布设桥梁,这样布设桥梁不仅确保了桥梁的结构安全性、满足行车舒适性的要求、也达到了施工便利、降低工程造价的目的。     

汽车平顺性计算程序设计

文章基于理论力学中的力学理论,建立了以悬架、轮胎为主体的分析平顺性的半车动力学模型。将此动力学模型转换成为易于求解分析的传递函数和状态空间形式的数学模型,并建立一定的道路模型,得到接近真实状态的汽车平顺性响应。在GUI界面下利用Matlab中的相关函数建立所求得的数学模型,实现对平顺性各响应相关量的求解。结果表明:本次程序设计方案是合理的、可行的。     

和谐HX_D1型大功率交流电力机车通风系统

介绍HXD1型大功率交流电力机车的通风方式,分析其通风系统的主要技术特点,并对其风量的控制、室内空气洁净度的控制、板翅式复合散热器的应用、电气屏柜的特点和空调系统舒适性的控制进行了说明。     

A dummy for the objective ride comfort evaluation of ground vehicles

A new device for an objective evaluation of ground vehicle ride comfort is presented. In this study, the ride comfort (frequency range 0–30 Hz) has been referred to the acceleration acting along the vertical axis (subject spine) and to the longitudinal acceleration (acting at the subject shoulders). Based on the experimental measurements of such accelerations on different human subjects seated on a car seat, a proper mechanical/mathematical model of the seat+subject has been derived. The derivation of the model has been performed by minimising the error between the measured and the computed accelerations. A prototype of the derived mechanical model has been actually built. Particular attention has been devoted to the construction of the springs, of the moving members and of the magnetic damper. All of the device parameters (mass, stiffness, damping) can be easily tuned. Finally, an experimental validation of the device has been performed. The device, while seated with the same posture of the corresponding human subject is able to reproduce (with reasonable accuracy) both the acceleration along the subject spine and the acceleration at the subject shoulders.     

基于EMD广义能量的列车车轮故障诊断技术

针对列车车轮故障诊断,研究基于经验模态分解(EMD)广义能量法诊断技术。首先对钢轨振动信号进行经验模态分解,选取出有效本征模函数分量并赋予权重系数,然后求出各分量的能量加权和作为该信号的EMD广义能量值,最后确定出正常车轮的EMD广义能量安全域阈值,判断车轮的故障状态。采用仿真的正常及故障车轮的钢轨振动信号进行实验,验证提出的方法对正常和故障车轮的识别准确率达到90%以上。     

Higher-order boundary element method for the interaction of a floating body with both waves and slow current

A hybrid boundary element method is suggested to solve the problem of the interaction of floating structures with both waves and slow current. A pulsating source and its mirror image referring to the sea bottom are adopted as the Green's function. The velocity potentials are expanded into an eigenfunction expansion in the outer region of the fluid domain while higher order elements are used to discretize the boundary surface surrounding the inner region. The method is validated by comparing calculated results for a circular cylinder with the semi-analytical solutions. The method is then applied to ellipsoids of various breadth and draft to investigate the influence of body shape on the wave drift damping.     

基于状态空间法的四分之一车辆模型分析

悬架系统是车辆行驶系统中的一个重要组成部分,主要用于吸收和缓冲车辆行驶过程中来自车轮和路面接触产生的振动,车辆行驶的平顺性主要靠悬架系统来保证。本文采用两自由度四分之一车辆模型对悬架系统动力学模型进行建模,结合状态空间分析法分析不同悬架等效刚度和阻尼、不同轮胎等效刚度、不同车辆载重等情况下对车辆行驶平顺性的影响,为悬架的优化设计提供参考。