黄延高速裢达沟特大桥1、5#墩0#段施工托架设计

本文对单肢0~#段托架进行详细理论计算,主要受力构件采用贝雷架拼装,托架安装、拆卸方便。     

混联式发动机后悬置支架有限元分析

发动机后悬置支架是动力总成的重要承载部件,其强度必须满足各种极限工况要求。本文利用Solidworks软件对发动机后悬置支架进行建模,利用Simulation软件进行有限元分析与结构优化。结果表明,优化后的支架有效地降低了关键部位的应力,提高了发动机悬置系统的安全性能。     

一种客车车顶型支架的制作工艺

简要介绍一种用于客车车顶的异型支架,并对支架结构、制作工艺和制作过程进行分析和设计。     

基于CATIA的中型客车气瓶支架强度分析

运用CATIA软件对一中型客车气瓶支架进行三维设计,对初步设计方案进行CAE静强度分析;在此基础上进行改进设计,并进行静强度以及振动、制动、转向三种工况下的强度分析。     

小“天窗”改造九跨式电分相施工模式探讨

既有九跨式双断口电分相因不能满足第6次铁路大提速要求而需对其进行改造.本文通过对新、旧电分相的对比及分析,提出了九跨式电分相原位置改造施工的模式,该模式不仅能克服天窗点短对施工的制约,而且能将施工对运输的影响降至最低.     

基于HyperWorks导向臂支架的结构优化及改进设计

针对某6×4牵引车复合空气悬架导向臂支架断裂原因进行了分析,排除导向臂支架的铸造缺陷、材料及工艺加工导致失效问题,最终确定导向臂支架的断裂原因主要是由于结构设计不合理导致断裂,在原结构的基础上,确保安装结构基本不变,运用catia三维建模和HyperWorks软件分别完成三种方案的三维建模和静强度分析,通过分析结果比对,改进方案相比原方案,重量降低了8%,疲劳寿命提高了13%,最后经过疲劳寿命分析和15000km的道路可靠性试验,改进后的导向臂支架满足设计使用要求,提高了经济效益。     

一座悬臂挂孔桁架旧桥的检测与评估

一座建成已近30a的悬臂挂孔桁架桥,日常交通负荷比较大。为考察该桥结构的实际技术状态,确保桥梁运营安全,组织了桥梁试验检测。该文介绍了对该桥进行检测评估的过程和方法,对同类桥梁的评估具有借鉴意义。     

雷堡坳大桥高墩稳定性分析

根据有限元计算方法,对雷堡坳大桥最大悬臂施工阶段的各种工况进行稳定特征值分析.结果表明,结构自重、施工临时荷载、挂篮等竖向荷载对结构稳定性起主导作用,尤其挂篮突然脱落、上部结构悬浇箱梁一端滞后施工一个梁段对桥梁结构的稳定性影响较大,增设横系梁可以提高桥墩的稳定性.     

无缝道岔受力与变形的影响因素分析

基于有限单元法,建立了无缝道岔纵向力与位移的计算模型,根据纵向力、线路阻力、钢轨及岔枕位移的相互关系建立平衡方程组,并采用牛顿迭代法求解。分析了轨温变化幅度、道岔号码、辙叉型式、辙跟型式、道岔群的联结方式、焊接型式、扣件阻力、道床阻力、限位器阻力、间隔铁阻力、线路爬行、铺设锁定轨温差、岔枕抗弯刚度等因素对无缝道岔受力及变形的影响。轨温变化幅度越大、线路爬行量越大、与相邻线路及道岔的铺设轨温差越大,对无缝道岔各部件的受力及变形越不利。而其它因素对无缝道岔位移及纵向力分布各有不同程度的影响,应综合分析,优化设计,才能确保无缝道岔各部件的受力及变形均在容许限度内。     

A probabilistic damage tolerance concept for welded joints. Part 1: data base and stochastic modelling

The present paper presents the necessary crack growth statistics and suggests stochastic models for a reliability analysis of the fatigue fracture of welded steel plate joints. The reliability levels are derived from extensive testing with fillet-welded joints for which the entire crack growth history has been measured, not only the final fatigue life. The statistics for the time to reach given crack depths are determined. Fracture-mechanics-derived crack growth curves are fitted to the measured experimental curves and the best fit defines the growth parameters involved for each test specimen. The derived statistics and distribution function for these parameters are used as variables in a Monte Carlo simulation (MCS). In addition a Markov model is developed as an alternative stochastic model. It is a Markov chain for which the discrete damage states are related to chosen crack depths in the material. This model works directly with the experimental time statistics. It is a “stochastic bulk approach” not involving any random variables or fracture mechanics modeling. Both models are fitted to the data base and scaled to in-service conditions. Both methods are compared and discussed. The aim is to provide data for the variables used in a MCS and to develop a Markov chain for fast reliability calculation, especially when predicting the most likely influence of numerous future inspections.