基于有限元法的骨架式电动汽车车身可行性研究

本文基于国外某款微型车设计了骨架式电动汽车车身结构,通过有限元方法,分析了其静态刚度和模态特性。分析表明,其弯曲刚度大大高于参考弯曲刚度,扭转刚度略低于参考扭转刚度,但差别不大,一阶模态频率高于车身的振动频率范围。本文最终验证了该结构的基本性能均满足设计要求,为电动汽车车身的设计开发提供了一条科学、低成本的设计思路。     

汽车前梁设计中有限元方法的应用

使用有限元分析软件,模拟汽车前梁台架试验条件,对设计的前梁进行静力学分析,模态分析以及疲劳分析,并根据分析结果对前梁优化设计改进,提高了前梁强度和疲劳寿命。从而缩短了产品设计周期,提高了产品质量和可靠性。     

钢筋混凝土拱桥有限元建模及动力特性分析

文章以重庆某预应力钢筋混凝土箱型拱桥为例,利用有限元分析程序SAP2000建立了桥梁有限元模型,对该拱桥模型进行动力特性分析,通过模态分析和时程分析研究了该拱桥在各阶模态下的振动周期、频率以及变形情况,为桥梁的健康监测系统在关键位置布置传感器提供依据,并得出一些有益的结论。     

基于位移模态叠加法的压力管道腐蚀损伤检测

基于结构模态分析原理,针对压力管道中常见的大面积腐蚀缺陷,给出了一种新的无损检测方法--位移模态叠加法.位移模态叠加法以位移模态作为模态分析的基本参数,通过对模态信息进行叠加、识别和优化,实现对缺陷的准确定位.该方法综合考虑缺陷位置及敏感振型对参数识别的影响,有效提高了位移模态方法的损伤识别能力.采用有限元分析软件AN...     

基于有限元分析的新能源汽车侧面柱碰结构优化研究

文章针对侧面柱碰工况特点对汽车车身结构的传力路径进行了分析,并以某款新能源汽车为分析对象,采用HyperWorks软件搭建有限元仿真计算模型,对侧面柱碰工况车身的主要传力路径上的座椅横梁和中通道进行结构优化,使其车身侵入量和电池包的安全性能均得到明显改善。     

冲压成形对汽车车门模态刚度的影响研究

汽车车门钣金主要是采用冲压成形工艺制造,而冲压成形导致的钣金厚度分布对模态刚度产生不容忽视的影响。在传统CAE分析中并没有考虑钣金厚度变化的影响,这与实际情况并不相符合。因此,本文将冲压成形仿真的厚度结果引入到有限元模型中进行模态刚度分析,并与传统分析和试验结果进行了对比,验证了考虑冲压成形的情况下,CAE与试验相关性更好。     

悬链线古桥的模态分析及加固研究

浙江绍兴嵊州的玉成桥为典型的悬链线结构桥梁,文章以其为研究对象,运用有限元软件ANSYS对其全桥结构进行弹性阶段的模态分析,获取结构的整体动力学性能,得到了其前十阶的振型和频率以及基频;同时针对该桥局部结构损坏情况,提出联合运用外粘钢板法和外粘贴碳纤维布法及压力灌浆的方式对该桥的关键部位进行维修的加固方案。     

某6101型客车车身骨架结构动态扭转响应分析

以某6101型客车车身骨架为研究对象,应用ANSYS软件,建立了其车身骨架结构有限元模型。采用客车驶过正弦波形路面的方式模拟右前轮越障的危险工况,分析了客车动态扭转过程中瞬态响应,得到了车身危险点的位移和应力的时间历程响应。结果表明:在动态扭转工况下,某6101型客车在0.045秒时最大应力达到130MPa,为改进车身结构提供了理论依据。     

有限元分析在洗扫车水泵支架轻量化改进中的应用

针对水泵支架质量稍重,不利于节能环保的问题,首先利用三维软件Pro/E建立符合有限元分析的三维模型,然后导入有限元分析软件Workbench,进行结构分析和模态分析,得到分析结果;根据分析结果有针对性的对水泵支架进行轻量化改进,然后再导入有限元分析软件Workbench进行结构分析和模态分析,验证轻量化改进的结果;经过对比分析结果,轻量化改进前后性能基本没变化,但重量下降了20%,从而验证了轻量化改进的效果。结果证明:改变传统类比的方法,借助限元分析有针对性的轻量化改进是可行的。     

基于小波变换和模态声发射的管道中导波传播特性的试验研究

基于小波变换和模态声发射理论,通过模态声发射试验的方法确定了管道中导波传播的频散特性。通过分析声发射信号的Gabor小波变换幅度在时频空间分布特点,确定某一频率下某一模态导波到达传感器的时间,从而确定该频率下该模态导波的群速度,进而确定其频散曲线。试验确定管道中频散曲线与理论计算曲线较好吻合,证明小波变换是分析频散波时频特性的有效工具。     

营运大客车正面碰撞乘员伤害的研究

客车发生正面碰撞事故约占客车碰撞事故的50%~60%。利用LS-DYNA软件,建立了包括假人、安全带和安全气囊在内的大客车车体有限元模型,对不同速度下营运大客车的正面碰撞特性进行了模拟仿真计算,分析了无任何保护措施、佩戴安全带及佩戴安全带且安全气囊起爆三种事故形态下乘员头部HPC值、胸部压缩量和大腿骨轴向接触力等伤害值。研究结果表明,安全带对于驾驶员的保护意义重大,为营运大客车乘员保护设计以及合理制定营运大客车正面碰撞法规提供数据参考。     

微型客车覆盖件抗凹性有限元分析与研究

文章运用有限元数值模拟方法模拟了车门外板凹陷变形过程,对其抗凹性进行了分析和评价,并采用数值模拟的方法对优化方案的可行性进行了验证。研究表明,有限元方法可以便利地预测和评定覆盖件的抗凹性能,为覆盖件结构的优化设计和材料选取提供理论指导和数据依据。     

A dynamic model system of household car ownership,trip generation,and modal split: model development and simulation experiment

A dynamic model of household car ownership and mode use is developed and applied to demand forecasting. The model system consists of three interrelated components: car ownership, mechanized trip generation, and modal split. The level of household car ownership is represented as a function of household attributes and mobility measures from the preceding observation time point using an ordered-response probit model. The trip generation model predicts the weekly number of trips made by household members using car or public transit, and the modal split model predicts the fraction of trips that are made by public transit. Household car ownership is a major determinant in the latter two model components. A simulation experiment is conducted using sample households from the Dutch National Mobility Panel data set and applying the model system to predict household car ownership and mode use under different scenarios on future household income, employment, and drivers’ license holding. Policy implications of the simulation results are discussed.     

钢管混凝土构件自振特性分析

钢管混凝土构件的自振特性（自振频率和振型）是结构动力特性分析和抗震设计的重要参数。文章根据结构自振特性分析理论,利用有限元模型对钢管混凝土构件的自振频率和振型进行了模拟分析,并阐述了自振频率和振型在桥梁损伤检测中的应用情况。     

基于半圆弯曲试验的有限元模型收敛性分析

文章采用有限元方法对半圆弯曲试验(SCB)进行数值模拟,对有限元模型建立过程中所涉及到的约束条件和单元尺寸进行了收敛性分析。分析结果表明:相对于单元尺寸,约束条件对SCB试件底部拉应力的影响较大;SCB试件底部支座处约束UY和UZ方向的位移计算有限元解与理论解吻合度较高;综合考虑计算精度和运算时间,SCB模型采用2mm的单元尺寸较为适宜。     

Neighborhoods,cars, and commuting in New York City: A discrete choice approach

Cities around the world are trying out a multitude of transportation policy and investment alternatives with the aim of reducing car-induced externalities. However, without a solid understanding of how people make their transportation and residential location choices, it is hard to tell which of these policies and investments are really doing the job and which are wasting precious city resources. The focus of this paper is the determinants of car ownership and car use for commuting. Using survey data from 1997 to 1998 collected in New York City, this paper uses discrete choice econometrics to estimate a model of the choices of car ownership and commute mode while also modeling the related choice of residential location.The main story told by this analysis is that New Yorkers are more sensitive to changes in travel time than they are to changes in travel cost. The model predicts that the most effective ways to reduce both auto ownership and car commuting involve changing the relative travel times for cars and transit, making transit trips faster by increasing both the frequency and the speed of service and making auto trips slower – perhaps simply by allowing traffic congestion. Population density also appears to have a substantial effect on car ownership in New York.     

Multimodal travel groups and attitudes: A latent class cluster analysis of Dutch travelers

For developing sustainable travel policies, it may be helpful to identify multimodal travelers, that is, travelers who make use of more than one mode of transport within a given period of time. Of special interest is identifying car drivers who also use public transport and/or bicycle, as this group is more likely to respond to policies that stimulate the use of those modes. It is suggested in the literature that this group may have less biased perceptions and different attitudes towards those modes. This supposition is examined in this paper by conducting a latent class cluster analysis, which identifies (multi)modal travel groups based on the self-reported frequency of mode use. Simultaneously, a membership function is estimated to predict the probability of belonging to each of the five identified (multi)modal travel groups, as a function of attitudinal variables in addition to structural variables. The results indicate that the (near) solo car drivers indeed have more negative attitudes towards public transport and bicycle, while frequent car drivers who also use public transport have less negative public transport attitudes. Although the results suggest that in four of the five identified travel groups, attitudes are congruent with travel mode use, this is not the case for the group who uses public transport most often. This group has relatively favorable car attitudes, and given that many young, low-income travelers belong to this group, it may be expected that at least part of this group will start using car more often once they can afford it. Based on the results, challenges for sustainable policies are formulated for each of the identified (multi)modal travel groups.     

CAE在波纹管成形数值模拟中的应用

文中应用有限元软件,对波纹管进行成形模拟分析。建模时须采用真实的结构参数,模拟波纹管成形过程。将有限元分析的结果同真实的试验数据对比,以验证分析精度,改进和优化成形工艺。试验证明：有限元法能够准确地对波纹管进行成形模拟分析,并且具有优越性,提高了波纹管的成形工艺水平。     

Network models for seat allocation on flights

This paper examines the problem of proper (optimal) control over the seat allocation on flights. Given a heterogeneous fleet of aircraft types, multi-leg flights, a number of different passenger categories, and cancelations, an airline's objective is to devise an effective system which aids in setting the seat allocation targets for each category of passengers on each flight. This issue is analyzed by a number of authors in the context of economic, simulation based, probabilistic, and mathematical programming studies. We present an attempt to address this problem from the systems prospective emphasizing characteristics such as: passenger cancelations, multi-leg flights, and rolling tactical planning time horizon. Starting from a very simple network flow models for a single flight with a number of intermediate stops, a number of progressively complex models are presented. The airline flights and the seat allocation system are represented as a generalized network flow model (with gains/losses on arcs) with the objective of flow maximization (profit maximization). This modelling approach does not claim to replace the seat allocation approaches presented in Alstrup et al. (1985), Mayer (1976), Richter (1982), Simpson (1985a), and Wang (1983), but rather construct seat allocations utilizing some of those referenced schemes in a parameter setting mode for a large network model. The objective of this paper is not to report on computational experiments, but to present a modeling approach which seems to be promising, if somewhat speculative.