三维渗流有限元软件GWSS开发与应用

针对复杂地质条件的三维地质建模、复杂建筑物的几何建模和复杂防渗排水系统作用下渗流场精细模拟等三维渗流场有限元分析的难点问题,采用IDL开发面向水工结构和岩土工程的渗流有限元分析软件GWSS（Ground Water Simulation System）.该软件包括系统控制模块、数据管理模块、前处理模块、计算模块、后处理模块和制图输出模块等六大模块.前处理模块具有基于钻孔和钻孔剖面的三维地质建模、几何建模与有限元网格生成等功能;计算模块主要用于各种闸坝、堤防、隧道和地下洞室等渗流问题的计算分析等;后处理模块可显示各渗流要素的三维云图和任意截面的二维云图等.GWSS已经在国内四十多个工程的渗流计算中得到应用和检验.     

基于HyperMesh 二次开发的无铆钉铆接

目前采用约束单元SPR2 建立无铆钉铆接的简化有限元模型,建模简单,仿真精 度较高,但HyperMesh 12.0 版本不支持SPR2 建模,导致了整车建模效率较低,因此本文应用 Tcl/Tk 语言和 HyperWorks 内置函数开发了整车铆接SPR2 的有限元快速建模模块。并以某轿 车铆接建模为例,验证了该模块的可操作性。该模块可根据用户选择的铆接点自动识别连接板 件,极大地提高了建模效率,同时可有效地避免软件的升级更新,节约费用,并为其他新型连 接的有限元快速建模提供了一种参考方法。     

基于Inventor的产品外观设计与实现

随着计算机技术的发展,计算机辅助设计(CAD)的水平有了很大的提高,CAD已不仅仅局限于进行二维图纸设计,而是能够建立真实地反映系统的三维实体模型,并且可以将多个三维实体模型装配为系统进行机构动态分析。Inventor是以实体建模为主,兼顾基础曲面建模的混合型三维建模的通用CAD软件系统。其核心组成部分为零件设计、装配设计、工程图纸;此外,Inventor还有一些特定行业的功能:动力学仿真模块、有限元应力分析模块、管路设计模块等。     

人字齿轮的参数化精确建模方法与虚拟装配

在常规齿轮建模中存在着渐开线和齿根过渡圆弧曲线精度不足以及装配误差容易造成干涉的问题,从加工齿轮的角度,以三维建模软件Pro/E为平台,采用参数化建模方法,对人字齿轮零件进行建模,并结合虚拟装配技术和Pro/E中的装配模块来完成零件的虚拟装配,建立相应两个人字齿轮的装配模型.通过在有限元计算和动力学分析中应用,其结果表明建模方法建立的模型精度相对较高,装配方法能有效的消除轮齿干涉,对提高有限元分析、机构运动分析、动力学分析的准确度奠定了基础.     

I-DEAS在高炉冷却壁传热分析上的应用

一、前言高炉冷却壁是冶金工业中一个重要的冷却设备,其使用寿命的长短在很大程度上取决于传热过程。过高的温度、过大的温度梯度、热冲击与热疲劳等常常会使冷却壁材质性能恶化而发生开裂、损坏,甚至会危及高炉安全。采用大型工程软件I-DEAS对高炉冷却壁传热过程进行了分析,并结合分析总结了使用该软件在热分析上的一些体会。笔者使用的软件为I-DEAS 8.0版（升级版,配有核心模块6个、二维绘图模块2个、曲面绘图模块1个、装配模块1个、有限元建模模块、有限元求解模块、热分析模块、寿命分析模块及变量化分析模块）。硬件采用HP L…     

基于Solidworks的线路行走装置的建模与仿真分析

借助Solidworks建模软件,对线路行走装置的各个零部件进行零件模型构建,完成后把零件进行装配,形成装配体;应用solidworks simulation模块对行走装置的行进滚轮进行有限元分析;最后利用solidworks motion模块对整个行走装置进行模拟仿真,仿真数据能够帮助我们分析行走装置的可行性,对不合理部件进行修改,受力分析能对整体方案进行合理评估。     

利科有限元分析软件开发

针对现有的通用CAE分析软件不能满足水工结构和岩土工程领域数值分析的需求,国内外还没有一款功能较完备的水工结构和岩土工程通用的CAE软件的问题,开发出面向水工结构和岩土工程设计、咨询、科研与高等教育的专业有限元分析软件——利科有限元分析软件(LinkFEA).计算模块的设置主要满足该领域中坝、闸、隧道和地下洞室、各类岩质土质边坡等中的渗流场、温度场、应力场(或位移场)及这3个场之间的耦合计算和结构安全性分析需求.前处理模块的功能有几何建模、有限元网格生成以及材料参数、载荷、初始条件和边界条件的设定等;后处理模块包括强度分析、渗透稳定性分析、边坡稳定分析和洞室围岩稳定性分析等,有限元计算结果和分析结果都能以等值线图或云图显示.LinkFEA已经过国内多个工程的渗流和应力(变形)计算的检验.     

缸内流体有限元预处理平台的输入模块设计

在气缸内流体有限元前处理平台中，input文件有四大模块：几何建模、工程分析条件确定、输出请求、自我管理。该文总结了input文件设计思路和方法。掌握其脉络对大型工程分析软件的设计和应用具有重要意义。     

基于虚拟样机的故障知识获取研究

文章利用CATIA软件对某型导弹发射装置发射台建模并利用工程分析模块Analysis＆Simulation进行有限元分析,获得导弹发射装置在载荷变化情况下的可视化资料,获取载荷一故障之间的对应关系,建立智能诊断专家系统知识库,为解决机电设备故障诊断专家系统知识获取的“瓶颈”问题提供了一个新的思路。     

模块化建模方法及其在车辆传动系中的应用

在分析了传统建模方法缺陷的基础上 ,提出了模块化建模方法的基本概念 ,并分析了模块化建模方法的特点 ,从模块划分、模块模型的建立、建模工具选择及建模时的因果关系几个方面阐述了模块化建模方法的运用 ,同时指出了模块划分中的关键问题及解决方法 ,并从模型验证的角度回答了可靠性及测试和仿真结果正确性如何检验等问题。最后以车辆传动系统建模为例 ,说明了模块化建模方法的应用。     

An operational approach to the design of workflow systems

We construct models as an aid to our thought process. A particular class of models, operational models, can be used for simulation and prototyping. The OPJ modeling language is suitable for building operational models of complex software systems.The notion of operational parameterized building block is the key point of the approach, which focuses on two major phases: domain modeling and system modeling. Domain modeling consists in providing the classes of the building blocks grouped into different schemata. System modeling consists in building an actual model using the building blocks taken from the above-mentioned schemata; such building blocks are connected to each other according to the rules expressed in the schemata and are given actual parameters.As an example, a workflow management system supporting business process managing travel authorizations is presented. The workflow system is modeled and then used to synthesize a distributed prototype.     

Fusion of 3D building models derived from first and last pulse laserscanning data

The work presented in this article is part of a project of collaborative research center 461: “Strong earthquakes”. Geometric modelling of buildings in urban areas, detecting and interpreting their changes is necessary to obtain fast damage information after earthquakes as important input for a disaster management system. Airborne laserscanning was chosen as data basis for this application due to its advantages like extensive independence of weather and lighting conditions, high accuracy and measurement density. Investigations have shown that building models created by means of laserscanning data have some systematic deviations compared to accurate reference models. Modern laserscanning sensors are able to record first signal response (first pulse) and last response (last pulse) simultaneously. Dependent on these modes the derived building models show system inherent differences: a principle enlargement using first pulse mode and an analogous reduction in last pulse mode. Their amount is dependent on the flights parameters and the resolution of the derived data set, here the enlargement was about +1.2 m and the reduction about −1.2 m. It will be demonstrated that a fusion of two models of a building, derived on the basis of first and last pulse data respectively, leads to an enormous accuracy improvement. At this state the fusion process is—according to the used quality assessment—divided into a positioning and height component. An algorithm for the determination of a centerline between the borderlines of the two building models will be presented. This line is used for adjustment of the position. For adjustment of the height, i.e. the roof structure, vertical distances inside corresponding planes of the two models are used to calculate a new adjusted one. The final building modelling is based on the intersection of these adjusted planes. The resulting building models fit much better to their related reference models. The mean positioning deviation decreases to ≈0.25 m, while the deviations in height are estimated between ≈0.02 m (flat roofs) and 0.10 m (steep sloped roofs). This significantly improved accuracy level lies below the accuracy of original laserscanning data and therefore enables, beside the recognition of building damages, a great variety of applications in urban environment like generation of 3D city models, e.g. for planning purposes.     

虚拟现实辅助机器人遥操作技术研究

本文以水下机器人的遥操作作业为应用背景,提出并实现了虚拟现实技术和视觉感知 信息辅助机器人遥操作实验系统．该系统使用了CAD模型和立体视觉信息完成遥操作机器人 及其作业环境的几何建模和运动学建模,实现了虚拟作业环境的生成和实时动态图形显示． 采用了基于立体视觉的虚拟环境与真实环境的一致性校正、图形图像叠加、作业体与环境位 姿关系建立、基于网络的监控通讯等关键技术．在这个实验系统中,操作人员可利用所生成 的虚拟环境,在多视点、多窗口作业状态图形和图像显示帮助下,实时动态地进行作业观测 与机器人遥操作与运动规划,为先进遥操作机器人系统的实现提供了经验和关键技术．     

Or models for energy planning

This paper discusses how OR models and methods have been used, or could be used, to aid in energy planning. The three specific areas discussed are energy system equilibrium analyses, energy R & D planning models, and models for stockpiling petroleum and allocating it in emergencies. A number of open methodological and model building research questions are presented.     

图形图像融合的海量建筑绘制

目的 城市3维模型数据海量且结构复杂,缺乏一个高效完善的可视化系统往往是影响数字城市应用的瓶颈之一。通常利用多层次细节（LOD）与调度算法减少每一帧绘制的数据量来提高绘制效率,当场景规模足够大时,即使采用复杂的优化算法也难以取得较好的效果。为此,本文在传统算法基础上,提出一种图形图像融合的海量建筑物场景绘制方法。方法 提出并采用视域分级绘制策略,将视椎体平行分割为感兴趣区域、次感兴趣区域和非感兴趣区域,感兴趣区域采用图形实时绘制方法,使用离屏渲染技术将次感兴趣和非感兴趣区域绘制在纹理图像中,每一帧绘制完成后将二者进行顾及深度信息的融合,实现完整场景渲染。结果 使用公开的纽约市区CityGML文件作为实验数据,数据包含了118 195个LOD1和LOD2级别的建筑物模型。分别构建多组不同建筑数量的场景进行帧率统计实验,绘制帧率都达到20帧/s以上。算法实现了视觉无损失的场景完整渲染,并与Cesium平台进行对比实验,证明算法有效且系统运行流畅。结论 图形图像融合的绘制方法,既保持了图形渲染的漫游连续性,同时也具有图像渲染的场景复杂度无关的优点。实验结果表明,针对大规模的低分辨率建筑模型场景,算法可以有效提高系统的渲染能力,在性能相对较低的硬件条件下也能实现海量建筑物实体模型的流畅漫游,并达到视觉无损失的场景完整绘制。     

基于Trnsys的水冷型中央空调系统建模与仿真

以广州某大厦水冷型中央空调系统为例子,利用Trnsys建立了大厦某层的多区域建筑及其中央空调系统能耗仿真模型,在此基础上分析加控制和不加控制2种情况下中央空调能耗情况。由2种模型的仿真结果可知中央空调具有很大的节能空间。模型主要用于研究中央空调运行的一些性质,对中央空调的节能优化控制具有重要的意义。     

Crowd simulation-based knowledge mining supporting building evacuation design

Assessing building evacuation performance designs in emergency situations requires complex scenarios which need to be prepared and analysed using crowd simulation tools, requiring significant manual input. With current procedures, every design iteration requires several simulation scenarios, leading to a complicated and time-consuming process. This study aims to investigate the level of integration between digital building models and crowd simulation, within the scope of design automation. A methodology is presented in which existing ontology tools facilitate knowledge representation and mining throughout the process. Several information models are used to integrate, automate and provide feedback to the design decision-making processes. The proposed concept thus reduces the effort required to create valid simulation scenarios by applying represented knowledge, and provides feedback based on results and design objectives. To apply and test the methodology a system was developed, which is introduced here. The context of building performance during evacuation scenarios is considered, but additional design perspectives can be included. The system development section expands on the essential theoretical concepts required and the case study section shows a practical implementation of the system.     

3D as-is building energy modeling and diagnostics: A review of the state-of-the-art

To achieve ambitious cuts in energy consumptions of the building sector, recent efforts have focused on devising methods that can provide accurate representation of the as-is conditions for existing buildings and in turn increase the quality and effectiveness of building retrofits. Today, 3D geometrical models produced by computer vision and laser scanning methods can be used as the basis of energy modeling purposes. Several methods are also introduced to facilitate the diagnostics and measurement of the thermal and other environmental conditions. To this end, this paper extensively reviews the state-of-the-art techniques that can semi-automatically or automatically create as-is geometrical and thermal models for building energy modeling and retrofit assessment purposes. It also provides an overview on the main algorithms used by these methods for representing spatio-thermal point clouds, automatically converting these point clouds into semantic Building Information Models (BIM) in gbXML format for as-is energy modeling purposes, and also contrasting them with expected energy performance models. The underlying formulations and methods for measuring actual thermal resistance of the building assemblies and mapping them into gbXML-based representations are also presented. The most recent works in the IT-driven building automation system (BAS) for energy conservation purposes are also reviewed. Finally, the technology gaps that need to be addressed in future research are identified and discussed.     

普适评估算法模型的实现

本文论述的评估算法模型主要针对常用的各类评估系统。这些算法模型有多种形式。文中详细地给出了其实现算法。这些算法模型具有很强的实用性。能为建立高效和功能强大的计算机评估系统提供参考。     

The Delft-FEWS flow forecasting system

Since its introduction in 2002/2003, the current generation of the Delft-FEWS operational forecasting platform has found application in over forty operational centres. In these it is used to link data and models in real time, producing forecasts on a daily basis. In some cases it forms a building block of a country-wide national forecasting system using distributed client-server technology. In other cases it is applied at a much smaller scale on a simple desktop workstation, providing forecasts for a single basin. The flexibility of the software in open integration of models and data has additionally appealed to the research community.This paper discusses the principles on which the Delft-FEWS system has been developed, as well as a brief background of the architecture of the system and concepts used for storing and handling data. One of the key features of the system is its flexibility in integrating (third-party) models and data, and the available approaches to linking models and accessing data are highlighted. A brief overview of different applications of the system is given to illustrate how the software is used to support differing objectives in the domain of real time environmental modelling.