大跨度拱桥减震分析

以西藏尼木大桥为研究对象,结合该桥型特点,采用大型通用软件对其进行了模态分析和动力计算.通过模拟地震响应得到该桥的反应特性,由此采用调谐质量控制器(TMD)对该桥进行受控分析.采用振型贡献率确定受控模态,在获取TMD系统的优化参数后将其模拟入有限元模型中,并最终通过时程分析验证了TMD运用于拱桥被动减震控制的有效性.     

高速客车转向架悬挂参数分析

为了全面考察转向架悬挂参数对高速客车行车安全性和乘坐舒适性的影响规律,为高速客车转向架悬挂参数的合理选取提供理论依据,首先从时域内分析了一、二系悬挂参数对高速客车动力学性能的影响,然后从频域内分析了二系悬挂参数对车体振动模态的影响.仿真计算与分析结果表明:合理设置一系纵向和横向定位刚度和二系抗蛇行减振器结构阻尼参数即可基本实现转向架较高的临界速度;减小二系横向刚度而适当增大二系横向阻尼可提高高速客车的横向平稳性;为了改善高速客车的垂向平稳性,一、二系垂向减振器阻尼都不宜选取过大.     

Regularization Method to the Parameter Identification of Interfacial Heat Transfer Coefficient and Properties during Casting Solidification

The accurate material physical properties, initial and boundary conditions are indispensable to the numerical simulation in the casting process, and they are related to the simulation accuracy directly. The inverse heat conduction method can be used to identify the mentioned above parameters based on the temperature measurement data. This paper presented a new inverse method according to Tikhonov regularization theory. A regularization functional was established and the regularization parameter was deduced, the Newton-Raphson iteration method was used to solve the equations. One detailed case was solved to identify the thermal conductivity and specific heat of sand mold and interfacial heat transfer coefficient (IHTC) at the meantime. This indicates that the regularization method is very efficient in decreasing the sensitivity to the temperature measurement data, overcoming the ill-posedness of the inverse heat conduction problem (IHCP) and improving the stability and accuracy of the results. As a general inverse method, it can be used to identify not only the material physical properties but also the initial and boundary conditions' parameters.     

On-line detecting of transformer winding deformation based on parameter identification of leakage inductance

Transformers are required to demonstrate the ability to withstand short circuit currents. Over currents caused by short circuit can give rise to windings deformation. In this paper, a novel method is proposed to monitor the state of transformer windings, which is achieved through on-line detecting the leakage inductance of the windings. Specifically, the mathematical model is established for on-line identifying the leakage inductance of the windings by applying least square algorithm （LSA） to the equivalent circuit equations. The effect of measurement and model inaccuracy on the identification error is analyzed, and the corrected model is also given to decrease these adverse effect on the results. Finally, dynamic test is carried out to verify our method. The test results clearly show that our method is very accurate even under the fluctuation of load or power factor. Therefore, our method can be effectively used to on-line detect the windings deformation.     

行波效应下连续粱桥随结构参数的响应分析

利用桥梁专用分析软件MIDAS/Civil建立大跨度连续梁桥多点激励数值模拟模型,采用国际上常用的Elcentro波作为加速度时程输入,在考虑行波效应和桩-土-结构相互作用的情况下,利用时程分析法求得结构在主跨跨径、固定墩纵向抗推刚度和边中跨比等结构参数下的响应峰值。通过数值分析比较,表明增大主跨跨径对结构抗震不利,减小固定墩纵向抗推刚度对结构抗震有利,边中跨比对结构抗震利弊兼半。综合分析各种结构参数,主跨跨径对结构抗震最为敏感。     

s-Conditionally Permutable Subgroups and p-Nilpotency of Finite Groups

A subgroup H of G is called s-conditionally permutable in G if for every Sylow subgroup T of G,there exists an element x∈G such that HTx=TxH.In this paper,we investigate further the influence of s-conditionally permutability of some 2-maximal subgroups of the Sylow subgroup of G,on the structure of finite groups.New criteria for a group G being p-nilpotent are obtained.     

立交匝道线形设计的探讨

在进行匝道的平纵横设计时,除灵活掌握技术指标外,还应最大限度地优化线形,使得其与主线能顺适连接,保证行车的安全性和舒适性。结合工程实践,提出在进行立交匝道的平纵横设计时应注意的一些细节,可供同行参考。     

铁路货车主要技术参数设计取值分析

在铁路设计工作中,货车平均长度、总重、静载重、每沿米重量等主要参数,对计算铁路行车量有较大影响,并影响到铁路的设备规模及运输能力．随着我国车辆技术进步,70t级车辆将代替60t级车辆,现行设计参数已不适应铁路的发展,本文对设计年度铁路货车主要技术数据进行了计算,提出了2020年、2030年铁路货车主要技术数据的修订意见,并结合设计实例对参数变化后的影响进行分析．     

列控车载设备控制程序及参数远程实时更新方法

针对既有列车控制系统不具备对车载设备控制程序及参数进行远程在线实时更新功能的问题,提出一种基于无线传输和嵌入式的列控车载设备控制程序与参数实时更新方法,在无线机车信号实际应用测试中表明,所实现的程序更新机制具有较高的适应性和可靠性,可有效提高运营中的车载设备程序升级效率,提高了对列车控制的安全性,降低了系统维护成本.     

监控环境下信号交叉口控制延误的获取方法

依据摄像头监控环境下可以检测到的相关参数,给出了信号控制交叉口进口道的车均控制延误参数提取的方法.文中以各个周期饱和度不超过1.2的信号控制交叉口进口道为研究对象,根据该周期的车辆通行需求和交通供给,将交叉口进口道的状态划分为正常交通状态和饱和交通状态;然后根据本周期车辆的到达情况、上周期排队车辆对本周期的影响及本周期排队车辆对下个周期的影响,结合监控环境下可以直接获取的相关参数,对两种交通状态分4种情况分析了交叉口进口道的控制延误参数的提取方法,构建了相应的模型.最后通过实例表明,该论文陈述的模型可以较好的提取交叉口进口道的控制延误参数.