乘用车车门刚度提升方案

用MSC Nastran对乘用车车门刚度提升方案进行研究,得到提升车门各方向刚度具体方案的实施效果.结果表明该实施方案可以有效提升车门刚度.     

Abaqus在轿车车门下沉量分析中的应用

为不影响轿车车门的使用,设计时会对车门下沉量设定设计目标.考虑几何和材料的非线性,搭建仿真分析模型,利用Abaqus的静态隐式求解方法完成某轿车车门下沉量的仿真和优化分析工作,保证该车前门的下沉性能.     

基于多工况的车门结构多目标优化设计方法研究

车门结构的单一工况优化设计常难以满足车门设计要求。本文基于车门垂直刚度和一阶模态两工况,提出一种车门结构多工况多目标优化设计方法。以车门垂直刚度、一阶频率和车门质量为优化目标,通过均匀拉丁方试验设计和响应面方法得出车门垂直刚度和一阶频率的近似数学模型,并在此基础构建车门结构多目标优化模型。最后采用多目标遗传算法对其进行求解,最终优化结果在车门质量减少的情况下,垂直刚度和一阶频率均达到设计要求,达到预期优化效果。     

地铁列车客室车门自动试验装置研制与应用

介绍了一种地铁车门自动试验装置,用于车辆组装完成后的车门调试试验;地铁车门试验是地铁电气静态调试试验的重要组成部分,而车门性能的优劣将直接影响到乘客的安全;针对地铁车门系统在车辆上的布置规律,综合各车门系统供货厂家的电气接口特点,制作车门自动试验装置,该试验装置可根据试验要求向地铁车门系统发送开门、关门、零速等指令,并实时采集各车门的开关、故障等总线信息,对车门状态进行显示、存储;通过使用该试验装置简易明了的展示了地铁各车门装置并对数据进行存储,最终证明车门自动试验装置可以缩短试验时间,提高试验效率的同时增加了试验数据的可追溯性.     

基于概念设计阶段的解耦模式车门截面形状优化方法

为了提高车门静态刚度, 采用基于HDMR理论的多参数解耦优化方法与Morph技术结合, 对一款处于概念设计阶段车门的主截面形状进行优化。这种建模方法的特点在于通过少量的样本点识别形状变量之间的耦合关系, 进而将高维问题进行分解, 在保证精度的前提下提高计算效率。采用Kriging插值方法对Cut-HDMR的各项进行构造, 得到车门各刚度下的考察点位移和质量的近似模型, 进而利用非支配排序多目标遗传算法（NSGA-Ⅱ）对近似模型进行优化, 在车门静态刚度均达到设计要求的前提下合理进行减重, 使垂直刚度和扭转刚度得到了很大的提高。     

城市轨道列车车门结构瞬态响应研究

针对城市轨道列车的实际受力环境,运用有限元分析方法对轨道列车车门门体部分进行了瞬态响应研究。对结构的模态、阻尼特性进行了深入研究,并以此为基础对整体车门结构的动态响应进行了分析,分析表明结构的动态应力和位移满足强度要求和使用条件,为结构优化设计提供了重要依据。     

飞行器空气舵系统的高效刚度分配优化方法研究

空气舵系统是飞行器典型操纵部件,其伺服作动器、连杆、摇臂、舵轴和舵面等子结构对空气舵系统的整体刚度有着不同程度的贡献,合理分配各子结构的刚度,可使空气舵系统的整体刚度得到进一步优化.本文提出了一种基于多体系统传递矩阵法和遗传算法相结合的空气舵系统高效刚度分配优化方法.首先,基于多体系统传递矩阵法建立了以结构尺寸和材料属性为参数的高效结构动力学计算模型,仿真结果表明,基于该计算模型所预测的空气舵第一阶俯仰模态固有频率与商业软件计算结果的误差仅为1.06%.其次,基于本文建立的高效结构动力学计算模型对各子结构刚度对空气舵系统动力学特性的贡献进行了灵敏度分析,给出了各部件对系统固有频率贡献的规律.最后,采取将遗传算法和多体系统传递矩阵法相结合的思路,以所建立的空气舵高效结构动力学模型为适应度函数,各子部件尺寸作为待优化变量,空气舵系统整体质量为约束条件,对空气舵系统各个子结构的刚度分配进行了优化.优化结果表明,在保持空气舵系统整体重量不变的条件下,可将空气舵系统第一阶俯仰模态固有频率提高约15.8%.     

一种轿车车门ECU设计

提出了一种"总体分布、局部集中式"的轿车车门ECU设计,ECU之间以CAN总线方式通信.以英飞凌公司XC164CS微控制器和TLE8201、BTS781功率驱动芯片为核心设计了车门ECU的硬件电路;在XC164CS上移植了μC/OS-Ⅱ实时操作系统,在此基础上进行了任务划分和应用软件设计,最后搭建了整个车门控制系统的实验台架.试验结果表明,该系统运行稳定可靠,达到了设计性能.     

考虑间隙运动副的桁架单胞等效建模与分析

本文主要研究了含间隙运动副桁架单胞的等效建模方法.主要考虑了桁架单胞的等效刚度问题以及阻尼问题.首先从间隙铰链开始研究,提出全面的铰链模型;其次提出用位移法将桁架单胞等效成板,即把桁架单胞看成是由梁元组成的钢架结构,运用平面钢架位移法得出桁架单胞的等效刚度矩阵,进而得出结构的整体固有频率和等效后的板的刚度矩阵.最后用有限元软件ANSYS对单胞结构在不同边界条件下进行了模态分析,将在自由边界条件下的固有频率和解析得出的频率做了对比,发现二者有很好的吻合度.结果表明由于间隙运动副的存在,使得桁架单胞结构的刚度降低,柔性增强.     

冲压成形残余效应对刚度分析的影响

针对冲压产生的板料厚度变化和残余应力等对有限元分析产生较大影响的问题,将冲压成形分析的网格节点厚度和塑性应变量等信息映射到车门总成刚度分析模型中,用MD Nastran分析车门刚度,并比较映射前、后车门刚度分析结果.结果表明在车门、内外板冲压成形残余效应影响下,车门总成刚度变化基本与料厚变化相吻合.     

Public transport accessibility measure based on weighted door to door travel time

Providing accessibility by public transportation is one of the main concerns in sustainable transportation development. An appropriate accessibility index should not only take transportation and land use into account but also the people who want to attend activities via the transport system. Travel time as the most common variable is used to indicate the role of transportation. A trip with public transport includes different parts: walking from the origin point to the bus stop or from the bus stop to the destination point, waiting for the bus to arrive, and in-vehicle time. These different parts have different weight values for passengers which affect their tendency towards traveling by public transportation. In this paper, a GIS-based multimodal gravity model is developed based on the weighted door to door travel time to compute accessibility by public transportation. Five main distinct urban activities including employment, education, healthcare, shop, recreation opportunities, and services are considered and the accessibility of the target population at the census block level to these destinations through public transportation is computed. In the next step, in order to consider all activities together and report a single unique index, the five computed accessibility indices are integrated into a composite index using a principal component analysis (PCA). The integrated accessibility measure helps to get an insight into the relative distribution of the benefits of public transportation and its interaction with the land use. The proposed method is applied to the City of Isfahan in Iran. The results indicate where places, for each activity and in overall, would benefit from the better land use and public transportation interaction and where regions would suffer from low accessibility level. This work provides a methodological framework as a tool for measuring the performance of public transportation and its interaction with the land use pattern.     

When one door closes, another door opens... [Editor's Remarks]

As customary for the last issue for each year, we express our sincere appreciation to the reviewers who have devoted their precious time to uphold the highest standard in the quality of this publication. We thank each one of you and hope you will continue to work with the new EiC in the years to come.     

Robust door assignment in less-than-truckload terminals

The assignment of incoming trailers to strip doors is one of the critical decisions that affect the performance of cross docking operations in less-than-truckload terminals. This paper introduces a mixed integer quadratic model with the objective of generating trailer-to-door assignments that equally distribute idle times at doors to accommodate operational level uncertainty encountered in truck arrival times. A door assignment heuristic is presented. The performance of the heuristic is compared with optimal solutions to small problems. The effectiveness of the proposed heuristic is studied under a variety of circumstances and terminal sizes. The simulation results show that the proposed heuristic is applicable to realistic-size terminals, and it is effective when variability in truck arrival and service times is considered.     

Into digital computing through the back door

From a hazy dream of writing a great American novel to heading up the renowned Lockheed Skunk Works, Sherman Mullin explains how he came to be an engineer-in digital computing, moreover, when the rest of the world was still mostly analog. Like most people who entered the digital computing field in the 1950s, he had no formal education in this technology. Like others, he learned mostly by doing. He began with the US Air Force, then moved to the Burroughs Corporation in Philadelphia. He progressed through various jobs and ended up as president of Lockheed Advanced Development Company.     

汽车车门过开启有限元分析

用Abaqus中的静力学分析功能,对某款车型前门进行过开启分析,得到此车门的过开角度和卸载后车门的残余角度以及车门和限位器的受力状况.同时,利用Abaqus中的MODEL CHANGE关键词,实现车门在过开启后,只有车门重新关闭而限位器保持不动的模拟,以此来考察车门能否关闭,从而更进一步评估传统的车门过开启分析方法.仿真结果表明:该车门过开性能满足设计目标,无破坏风险,且MODEL CHANGE关键词可以为模拟车门的关闭提供极大方便.     

飞机登机门门区结构设计及优化

优化设计可以改善结构的应力分布,合理布置材料,从而提高材料的利用率.在完成飞机登机门门区结构的初步设计后,通过对登机门门区结构逐层分解,确定优化设计变量、优化区域以及响应约束,并应用MSC Nastran进行优化,初步确定登机门门区结构尺寸.