基于参数化技术的隧道三维建模方法

针对已有隧道三维建模方法缺少交互性和多样性的不足,提出了基于参数化建模技术的隧道三维建模与景观仿真方法。试验表明,该方法能够快速和有效的建立多种景观隧道三维模型,能将隧道三维设计与三维场景形象直观的表现出来,满足隧道三维建模快速、多样性和交互性的要求。     

输电线路三维建模在线路日常巡维中的应用

输电线路日常维护是保证输电线路健康的重要措施之一,而输电线路巡线路径的记忆及巡线结果的记录是巡维工作中需要解决的其中两个棘手问题。本文充分使用GIS及三维建模技术,为输电线路建立三维模型。利用输电线路三维模型,协助输电线路巡维人员记忆巡线路径及记录巡线结果,以帮助巡维人员更好的完成输电线路巡维任务。     

高速列车运动仿真可视化建模研究

以CRH系列高速列车为研究对象,建立了基于变参数的列车三维动态仿真模型,实现了多种列车单元模型在运动过程中的实时调入和装配,满足了高速列车运动仿真多样性的要求。采用Visual C++6.0、OpenGL三维图形库和Oracle数据库开发完成高速列车运动仿真系统,实现高速列车运动仿真可视化建模以及与线路设计之间的有效集成。通过实际应用,取得了较好的仿真效果。     

基于GIS的铁路路基三维可视化技术研究

在线路的三维建模中,路基三维模型与地形三维模型的交接、融合是关键技术和难点.首先分析了当前路基三维建模的方法,然后基于GIS平台,研究路基模型与地形模型的叠加,最后利用GIS控件实现了路基的三维建模和可视化.在实际铁路选线的应用中,证明了此方法的适用性和高效性.     

公路隧道三维建模与可视化实现

采用三维可视化技术，实现了公路隧道的三维建模与可视化表达。详细论述了地形、隧道构造物以及公路附属设施的三维模型建立方法，探讨了三维对象模型与地形模型的匹配问题，在此基础上分析了公路隧道三维可视化过程。通过具体事例表明该方法能将虚拟的工程面貌与三维场景形象直观的表现出来，具有很好的应用性。     

基于Simulink的输电线路故障行波仿真方法的研究

提出了基于MATLAB／Simulink的输电线路故障行波仿真方法。首先建立了基于MATLAB／Simulink的仿真模型,并对各个模块的参数设置方法和功能实现以及输电线路故障行波的提取算法进行了详细的说明。仿真实例表明,该仿真方法具有可行性,而其实现了在同一个仿真软件内对故障行波的仿真和分析,具有实用性。     

输电线路三维数字化建模及其在地理信息系统中的应用

针对输电线路模型在三维地理信息系统中的真实、高效导入和展示问题,提出了输电线路组合建模的方法,并对影响线路设备模型姿态的关键问题——电线模拟算法,进行了深入分析比较。通过实例验证了上述方法的有效性,既保证了电网模型对电网设备的真实反映,又提高了三维系统运行速度和效率,为后续电网相关业务深入应用奠定良好基础。     

基于两种轨道线路建模方法的地铁车轮磨耗预测对比分析

轨道线路对车轮磨耗具有重要影响。建立地铁车轮磨耗预测模型，模型包括车辆动力学模型、基于Hertz理论和FASTSIM算法的轮轨局部接触模型、基于Tγ/A-磨损率函数的磨耗模型、平滑与更新策略以及轨道线路模型。对比分析等效轨道线路法与真实轨道线路法两种轨道线路建模方法在建模复杂度、车轮磨耗预测结果与计算效率方面的差异。利用实测的车轮磨耗对Tγ/A-磨损率函数进行修正，并对磨耗预测模型进行验证。结果表明:与等效轨道线路法相比，真实轨道线路法建模较为复杂，但其可以更好地模拟实际轨道线路；二者磨耗预测结果差异较小，且均与实测结果较为吻合，但前者计算效率约是后者的3.7倍。采用等效轨道线路法建模可以较好地兼顾计算精度与效率。     

输电塔架参数化三维建模方法研究与实现

快速建立输电塔架三维仿真模型对电网安全运行与信息管理有重要作用.根据输电塔架的结构特点及结构相似性进行模块化划分,并用参数化方法为相同结构型式的模块建立原始三维模型;在此基础上根据塔架型号与呼高,对各模块进行选择与组装,赋值参数驱动各模块的原始模型,实现各种塔型与呼高的塔架三维快速建模.以某酒杯型直线塔为例,输入塔架型号与呼高即实现其三维模型快速建立,验证了该参数化三维建模方法的正确性与实用性.     

基于ArcGlobe的三维数字校园建模与仿真

数字校园是数字城市的缩影,是虚拟校园建设的支撑平台。在综合分析现有三维数字校园建设的基础上,以山东科技大学青岛校区为例,引入ArcGlobe软件,讨论了数字校园建设的数据来源与处理方法、三维校园仿真的技术流程、不同起伏度的地面三维模型的构建方法、地物景观模型的构建技术等。给出了三维校园仿真的具体实现方法,采用LOD和动态纹理匹配技术提高了三维建筑物加载和绘制的速度。论文给出的数字校园仿真与建模的方法对正在开展的数字校园与数字城市建设具有较强的指导意义。     

基于虚拟仿真技术的灌装生产线设计与仿真

目的 针对灌装生产线的设计与验证过程,基于虚拟仿真技术,实现灌装生产线的快速设计与验证。方法 首先通过分析灌装生产线的生产过程,利用SolidWorks三维建模软件分别对灌装生产线中的灌装机、搓盖机、贴标机、喷码机、装箱机等设备设计三维模型。然后将所有设备的三维模型导入Demo 3D仿真软件,进一步按照各设备的动作流程对模型进行动作设计及运动规划,构建灌装生产线虚拟仿真系统。最后根据设备功能和生产产能要求,在虚拟仿真系统中通过不断地调整设备机械结构及机构的运行速度,最终实现灌装生产线的快速设计与迭代优化。结果 得出灌装生产线的优化设计方案,并根据该设计方案研制出灌装自动生产线,生产线的产能为2400 瓶/h,满足企业要求。结论 该方法能够实现灌装生产线的快速设计与验证,缩短设计开发周期,减少设计和验证成本。     

Production line 3D visualization monitoring system design based on OpenGL

New production line management technologies are required and adopted recently with the development of modern manufacturing industry. In this study, a production line three-dimensional (3D) visualization monitoring system based on OpenGL modeling, open database connectivity (ODBC), and database management technology is established on a VC++6.0 platform to satisfy effective production. A client/server model is adopted in the system, and data on processing information, interactive operation, and failure process are stored in the server side database. A client reads the workpiece process information from the server, and the machining process of every workpiece is visually represented in the form of 3D visualization. Production line 3D visualization provides production capacity simulation to optimize the parameter settings. When compared with the analysis results of production line capacity, the key parameters possess the same optimal values, and this proves the accuracy of production line 3D visualization monitoring system. The system provides effective data support for production line monitoring and management in enterprises. The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-018-0217-x     

Comparative Modeling of Protein Structure—Progress and Prospects

Comparative modeling of protein structure is a process which determines the three-dimensional structure of protein molecules on the basis of amino acid sequence similarity to experimentally linown structures. The procedure is facilitated by the growing database of protein structures obtained from crystallography. In this review a series of stages in the modeling process are identified and discussed. These are: (i) obtaining a reliable amino acid sequence of the structure of interest, (ii) producing a structurally correct sequence alignment, (iii) identifying which structural features are conserved between target and parent structures, (iv) modeling the new pieces of structure, and (v) tests of reliability.     

细编穿刺织物的数学建模理论与实例

针对细编穿刺织物,采用具有参数连续性的样条线作为纤维丝束的轨迹特性函数,建立了三维立体织物结构的数学抽象与三维建模方法。基于MicroCT方法实际测量的细编穿刺织物结构特征参数,采用四种丝束轨迹特性函数和两种丝束截面建立了八种穿刺织物结构的三维数字模型,通过丝束结构与孔隙率的对比,三维数字模型与织物真实结构符合较好。该织物结构数学抽象与三维建模方法,可用于小尺度的亚单胞模型与大尺度的宏观模型分析,具有较高的适应性。     

颗粒团聚分布的复合材料数值模型

目的 提出颗粒团聚分布的数值模型参数化建模方法,以高效建立颗粒有序分布的复合材料微观构型。方法 以颗粒尺寸、颗粒团聚区域的半径以及团聚区域局部体积分数和整体体积分数的比值作为表征颗粒团聚结构的基本建模控制参数,首先建立了圆形/球形区域内的Voronoi多胞元结构,其次编写基于Python语言的接口程序,根据角点坐标和几何拓扑关系将多胞元结构导入有限元软件中,并对每个胞元按团聚区域局部体积分数进行缩放,形成了圆形/球形区域的颗粒团簇,最后使用随机顺序吸附算法将团聚颗粒在代表单元内周期性随机投放,生成了颗粒团聚分布的复合材料二维/三维微观构型。结果 使用不同控制参数进行数值建模测试,生成一个颗粒数目在1 000以内的二维/三维颗粒团聚微观构型仅需要数分钟,验证了本文方法的有效性。使用二维模型对单轴拉伸进行数值模拟,结果表明,材料宏观塑性随着颗粒团聚程度的增大而降低。结论 本文建模方法可以为复合材料结构设计提供有效的数值仿真支撑。     

Calibration modeling for mobile vision based laser imaging and approximation networks

A mobile calibration technique for three-dimensional vision is presented. In this technique, the parameters of mobile vision are computed automatically by approximation networks and image processing of a laser line. Also, the three-dimensional vision is performed by the networks. The proposed vision system provides online geometric modifications from the initial configuration. Here, an online re-calibration is performed via network data to determine the setup modifications. Thus, vision limitations caused by the geometric modifications are overcome. The network is built based on the behavior of the laser line and the camera position. In this manner, the network provides the data for the automatic re-calibration. This system avoids calibrated references and external procedures for re-calibration. Therefore, the calibration model improves the accuracy and performance of the mobile vision. It is because the external data are not passed to the procedure of the three-dimensional vision. This kind of modeling represents a contribution for calibration of mobile vision. To elucidate this contribution an evaluation is carried out based on the calibration via perspective projection model. The time processing is also described.     

Prediction of structural response for low velocity impact

The complete modeling for impact on flexible structures can always be done through a three-dimensional finite element model. The FEM approach is often very costly both from modeling and calculation duration point of views, so it can be simplified by using simplified impact models. The selection of an impact model depends on the structural response, thus one should be able to predict the expected structural response a priori in order to select an appropriate impact model. Impact duration is an important parameter that can be helpful for predicting the expected structural response. This paper provides guidelines for the prediction of the structural response on the basis of impact duration and the fundamental period of the impacted structure. A criterion for defining a precise upper limit of low velocity impact is also developed.     

Mechanics of three-dimensional braided structures for composite materials – part I: fabric structure and fibre volume fraction

This paper is the first part of a series on the mechanics of three-dimensional braided structures for composite materials which include fabric structure and fibre volume fraction models, prediction of mechanical properties, finite element analysis and simulation of deformations. In the present paper, the normalized pitch length is introduced as a key parameter of three-dimensional braided structures. It is demonstrated that the braiding angles and fibre volume fractions can be represented as functions of this key parameter. The structures of three-dimensional braids were simulated and the braided fabrics and preforms were designed and produced. Fibre volume fraction models were established. The predictions from the fibre volume fraction models are supported by experimental results.     

计算机辅助结构设计与分析的集成框架研究

针对计算机辅助结构设计和分析的集成问题,设计了一种基于统一模型库方式的组件式CAD/CAE集成框架,以结构CAD/CAE集成模型库为框架底层,以几何造型、可视化交互、第三方CAD、第三方CAE等组件为中间组件层,以空间结构设计子系统、空间结构分析子系统为上层应用层,提供空间实体建模、工程模型管理、多种有限元模型分析与计算等功能,并应用于港口码头的结构设计及有限元分析。