Three‐dimensional modelling of differential railway track settlement using a cycle domain constitutive model

A method for simulation of differential (spatially varying) track settlement in a ballasted railway track is presented. It employs a cycle domain constitutive model to determine accumulated plastic (permanent) deformation of the granular layers supporting the track. The constitutive model is adopted for both the ballast and the sub‐ballast but with different parameter sets. The proposed framework can be used to predict differential track settlement accounting for heterogeneous (space‐variant) track characteristics and loading conditions. Here, it is demonstrated for three‐dimensional continuum modelling of a railway crossing panel subjected to a large number of axle passages. Because of the design of the crossing panel and the transient character of the impact loads on the crossing, the load transferred into the track bed is not uniform along the track, and the resulting differential settlement leads to vertical irregularities in track geometry. The spatial variation of track settlement is calculated both along the sleepers and along the rails. The influences of the number of adjacent sleepers accounted for in the model and the stiffness of the subgrade on the predicted settlement at the crossing are studied. Copyright © 2016 John Wiley & Sons, Ltd.     

The Relation between Tectonic Movement and Climatic Change

1SeesawphenomenonofoceaniccrustSince 1996, Yoshino etal.(2002) have been us-ing the space geodetic techniques to observe crustal deformation at four sites in Tokyo metropolitan area. It is called Keystone project (KSP). At the end of June in 2000, volcanic and seismic events star-ted at Izu islands, south of Tokyo. Following the ev-ent, extraordinary crustal deformation was observed not only around the Izu islands, but also at the Key-stone network, where the closest site is over 100…     

基于Abaqus软件的并行计算异构集群平台的搭建

在异构集群上充分利用新、旧硬件资源调度计算任务是实现集群高性能并行计算的难点。通过测试已搭建集群服务器的CPU和内存对Abaqus软件计算速度的影响,发现CPU的主频对Abaqus/Explicit模块计算速度的影响大,CPU的缓存对Abaqus/Standard模块速度影响大;当内存满足计算任务的最小需求时,增加内存对计算速度无任何影响;当内存不足时,计算速度会大幅减慢。据此测试结果,新增4台服务器作为计算节点和一台Infiniband QDR交换机作为交换节点,搭建了新的异构集群,性能测试结果表明:相对于千兆以太网络交换机I,nfiniband QDR交换机的并行计算效率更好,且集群的计算节点越多越显著;Abaqus/Standard模块并行计算效率的提高幅度要比Abaqus/Explicit模块的稍高一些。针对异构集群硬件构架相差较大的2批新、旧硬件,设置了2个管理节点、2个网络节点、2个存储节点,充分利用了新、旧硬件资源,高效地实现了在一个异构集群平台上提交与下载任务。     

水位骤降条件下有密集排水孔大坝三维渗流场数值模拟研究

对于坝坡布置密集排水孔的工程渗流问题,水位骤降条件下密集排水孔排水效果及坝体和坝基内三维渗流场分布是工程设计人员关心的重要问题。针对坝坡布置排水孔的渗流行为,提出了密集排水孔在水位骤降下渗流状态改变的处理方法。并详细论述了改进的截止负压法求解饱和-非饱和渗流场、排水子结构法和排水孔开关器等精细模拟排水孔的关键技术。工程实例表明,采用该方法可以有效地解决水位骤降下上游坝坡布置密集排水孔三维渗流场的精细数值模拟问题。     

Enhancement of real‐time hybrid simulation on a shaking table configuration with implementation of an advanced control method

This paper presents the implementation of Three Variable Control (TVC), an advanced control method, to the existing hybrid simulation (HS) system at the University of California, Berkeley. Motivation, background, and implementation of the TVC are explained together with modifications in the existing HS system. An application, which consists of the real‐time HS of electrical disconnect switches on a shaking table configuration, demonstrates successful implementation of the TVC. The presented application also covers other HS‐related features, namely employment of a three‐dimensional analytical substructure, real‐time HS‐compatible operator‐splitting integration method, and an efficient equation solver for faster computations. Copyright © 2014 John Wiley & Sons, Ltd.     

从数字城市到智慧城市——攀枝花智慧城市建设初步探讨

文章对数字地球、数字城市、智慧地球、智慧城市等相关概念、理论进行了初步梳理和剖析。以数字城市到智慧城市的认知转变入手,阐述了我国建设智慧城市的特征和意义,并以攀枝花市为实例,在介绍其数字城市框架建设的基础上,讨论并提出了攀枝花建设智慧城市的若干对策。     

SS—1型地震开关的研制

地震报警系统的开发与部署已受到广泛的关注。地震开关是其中关键的技术手段。研究表明：地震发生的Ｐ波与Ｓ波具有不同的传播速度与振动方式，Ｓ波是造成震灾的主要原因而其传播速度要经Ｐ波慢得多。根据Ｐ波振幅与震灾的关系及其振动方式、频率域、时间域的特征，可以从干扰背影中同地震时首先到达的Ｐ波，如符合判据，就发出报警信号及控制命令；疏散人员，切断次生灾害源，达到减灾的目的。通过响应调整可以排除一些人为的、自然     

带减震支座的T型开关设备地震响应分析及试验研究

已有震害资料表明,支柱类设备具有较高的地震易损性。本文中提出使用钢丝绳及液压阻尼器组成的复合减震支座减小T型旁路开关的地震响应。本文首先分别对固定支座、钢丝绳阻尼器支座和复合支座的旁路开关进行有限元分析。随后对带复合减震支座的旁路开关进行了振动台试验,识别设备多阶振型,利用加速度响应及质量分布计算各截面弯矩,使用频响函数推算支座的减震效果。结果表明,液压阻尼器可以在钢丝绳阻尼器的基础上进一步减小设备的应力及位移响应。T型旁路开关基频较低且易受到高阶振型影响,设备支柱绝缘子中上部加速度响应最大,顶部位移最大而根部应力最大。减震支座能将设备的应力和位移响应减小大约50%,且设备的应力响应满足安全系数要求。     

考虑不同支架形式放大效应隔离开关地震响应分析

高压隔离开关作为变电站系统中的关键设备,提升其抗震性能对变电站的稳定性具有重要意义.通过Abaqus建立有限元模型,运用增量动力时程分析方法,研究了110kV隔离开关固有频率、放大系数随结构支架截面、高度和和瓷套管材料的变化规律.同时进一步研究了不同支架尺寸参数和不同瓷套管材料下隔离开关易损性特性.结果 表明:支架截面...     

中尺度对流系统引发的致灾雷电过程分析

本文对2007年3月3日-5日华北区域爆发的强寒潮,从大尺度环流形势特征、天气过程特点及特强降温的成因进行了分析,得出了强寒潮天气爆发预报着眼点。此次寒潮天气是由于西路冷空气和极地冷空气在贝加尔湖附近地区合并加强;横槽转竖,偏北气流引导冷空气南下,并且又有补充冷空气南下造成的。欧亚500hPa中纬度大“Ω”流型为寒潮天气的产生提供了有利的环流背景。该大“Ω”流型与常见寒潮倒“Ω”流型的槽脊位置在东北亚地区接近反位相。且波长更长。