综合接地对AT牵引供电网络参数影响的研究

建立了一个由16根平行导线构成的广义四端网络表征AT供电系统模型,以沪宁高铁无锡区段某供电臂为实例,计算与分析了综合接地系统接入后对钢轨电位、牵引网阻抗、钢轨及大地回流的影响.计算数据表明,综合接地对钢轨电位的降低有显著的作用,而对牵引网阻抗的大小几乎没有影响.     

高铁隧道平面控制网横向贯通误差仿真研究

构建附合单导线、导线环网、交叉导线网和自由测站边角交会网等4种常见的高铁隧道洞内仿真平面控制网,利用精度估算的方法计算这4种网型在9种不同隧道长度情况下的横向贯通中误差;基于Box-Muller算法为仿真控制网添加随机误差,利用稀疏矩阵行列压缩技术对附加随机误差的控制网进行快速严密平差计算,从而完成4种隧道洞内平面控制网横向贯通误差的仿真计算工作。计算结果表明自由测站边角交会网的横向摆动相对较小,可以替代传统的洞内导线网;证明隧道洞内平面控制网的横向摆动服从正态分布,适当增加测量次数,可提高隧道的横向贯通精度,对确保长大隧道正确贯通具有参考意义。     

高速铁路水下盾构隧道管片内力分布规律研究

以在建的广深港高速铁路狮子洋隧道为背景,采用自行开发的"多功能盾构隧道结构体试验系统"装置,对大断面宽幅管片衬砌结构在通缝及错缝拼装方式下环向内力的分布规律进行原型试验实测与分析,并对正弯区和负弯区目标管片表面应力的分布进行测试,同时采用数值计算进行对比分析。研究结果表明:通缝拼装管片结构内力沿幅宽的变化很小,而错缝拼装管片结构在不同荷载条件下,内力沿幅宽的分布有所差异,水压越大其差异越小;管片手孔密集区往往会出现应力集中,同等条件下正弯区表面应力状态比负弯区更为不利;管片厚度方向表面应力分布呈显著的非线性变化,高水压使其非线性变化加剧。     

新型GFRP组合梁桥的空间分析

对拉挤成型GFRP组合桥面板和工字形钢梁组合而成的新型GFRP组合梁桥进行了空间有限元分析,通过对横隔板、纵梁跨径及间距等参数的研究,得到该组合梁桥横向分布系数随上述参数变化的规律.     

某型配电柜空间热场分析

以某型配电柜为研究对象,采用传热学计算方法,计算在环境温度下配电柜内的温度场.利用计算结果的参考作用,对配电柜外壳进行散热优化.计算与试验结果表明,配电柜外壳改进设计合理,内部温升指标均可满足规范要求.仿真研究分析的方法和结论对配电柜散热设计具有参考价值.     

功率混合型燃料电池汽车动力系统的恒压式能量分配算法

分析了功率混合型燃料电池汽车动力系统的特征,给出了功率混合型动力系统能量分配算法的实用设计原则,阐述了该型动力系统适用的恒压能量分配方式,并依据提出的设计原则进行了能量分配算法设计。在燃料电池城市客车“清能3号”的应用中,又提出一种分模式控制解决方案。实验证明,所设计的算法能综合考虑动力系统的部件安全性、动力性和经济性,具有一定的应用价值。     

Development of destination choice model with pairwise district-level constants using taxi GPS data

In this paper, a destination choice model with pairwise district-level constants is proposed for trip distribution based on a nearly complete OD trip matrix in a region. It is found that the coefficients are weakly identified in a destination choice model with pairwise zone-level constants. Thus, a destination choice model with pairwise district-level constants is then proposed and an iterative algorithm is developed for model estimation. Herein, the “district” means a spatial aggregation of a number of zones. The proposed model is demonstrated through simulation experiments. Then, destination choice models with and without pairwise district-level constants are estimated based on GPS data of taxi passenger trips collected during morning peak hours within the Inner Ring Road of Shanghai, China. The datasets comprise 504,187 trip records and a sample of 10,000 taxi trips for model development. The zones used in the study are actually 961 residents’ committees while the districts are 52 residential districts that are spatial aggregations and upper-level administrative units of residents’ committees. It is found that the estimated value of time dramatically drops after the involvement of district-level constants, indicating that the traditional model tends to overestimate the value of time when ignoring pairwise associations between two zones in trip distribution. The proposed destination choice model can ensure its predicted trip OD matrix to match the observed one at district level. Thus, the proposed model has potential to be widely applied for trip distribution under the situation where a complete OD trip matrix can be observed.     

客户配送要求变动下的VRPSDP干扰管理优化

为解决客户配送要求变动对VRPSDP方案造成的干扰问题，从成本和服务时间两个方面，就干扰事件对原物流配送车辆路径方案造成的影响进行了干扰辨识分析.构建了VRPSDP干扰管理模型，并设计基于禁忌搜索的调度算法.从Solomon标准测试算例中随机抽取6组算例对模型和算法的有效性进行验证.结果显示，本文的干扰管理方案与传统的增派车辆和全局重调度方案相比较，广义总费用偏离有明显地降低，且本文方法能够在较短的时间内生成满意的物流配送车辆调度调整方案.     

On the application of the Haskind-Hanaoka relations to hydroelasticity problems

The Haskind-Hanaoka relations for obtaining the wave-exciting forces, given the incoming and radiation potentials in floating rigid-body dynamics, are extended to deformable-body dynamics in the presence of a free surface and within the assumption of linear potentials theory. These relations are applied to the mode-superposition and the direct methods of solution of hydroelasticity problems. In other words, it is shown that regardless of the structural analysis method used in a hydroelasticity problem, the Haskind-Hanaoka relations can be used to calculate the wave-exciting forces without solving for the diffraction potential explicitly. These relations can also be used in the composite singularity distribution method to increase further the computational efficiency.     

磨粒分布函数及可靠性数学用于部分弹流中接触：概率与磨损研究

本文提出一种实际机械中的润滑均为部分弹流状态的新观点.文中利用磨粒尺寸分布函数及可靠性数学方法解决了部分弹流中接触概率的计算和磨损规律,并进一步提出了设计计算时,接触概率的控制规范.