二维特征造型方法的研究

本文根据实际需要对二维特征造型方法进行了研究，目的是改造传统CAD系统，以支持CAD/CAPP的集成。采用的方案是，特征设计和特征识别相结合，提出形状特征作为精度特征的载体，第一步是用形状特征设计，第二步是进行精度特征识别以得到完整意义上的特征，进而满足CAPP的需要。     

机械CAD中的参数造型

机械CAD正由传统的二维工程图纸模式的三维实体模型转换，设计概念正向CAD／CAM集成发展，参数特征造型是实现CIMS关键五一节。本文介绍了参数造型的设计概念和实现方法，简单叙述了如何用商业软件AutoCAD二次开发进行参数造型的过程。     

利用二维图形进行三维建模的应用研究

在计算机辅助设计(CAD)应用工程中，利用已有的二维工程图进行三雏模型的设计，是一个十分重要的研究内容。文章对此进行了探讨。以叉车的连接支座为例，利用CAXA电子图板把工程图转换成Inventor三维设计软件可以直接输入的文件类型。在Inventor中对其进行处理，提取出特征造型用的轮廓线和几何图元，添加尺寸和约束，在此基础上利用特征造型工具。创建三维零件模型，并进一步以叉车的整车模型为例分析了三维建模中零件装配和仿真分析的有关问题。     

基于产品识别的矿山机械造型设计研究

针对矿山机械产品缺乏识别设计的问题,在造型设计环节引入产品识别。以矿山机械产品通用特征形式、标准特征形式和自由特征形式为基础,结合矿山机械产品意象风格识别,构建特征元素、特征面和造型风格意象的设计方法。以电动轮自卸车造型设计为例,对竞争产品进行调研分析,运用产品意象试验获取电动轮自卸车关键特征,并将企业文化与设计趋势融入方案,设计全新造型。     

基于特征建模的汽轮发电机转子参数化设计

以UG／NX三维CAD实体建模软件作为平台,利用UG／OPENAPI二次开发技术,实现了基于特征建模的汽轮发电机转子参数化设计。完成了对汽轮发电机转子本体造型特征建模,以实例演示了转子本体造型参数化设计过程,并建立起了能够快速检索的特征模型库,加强了产品设计的可重用性,实现了“三维设计,二维出图”的自动化输出。     

液压集成块3维参数化设计研究与应用

采用特征对象化的设计思想，在特征造型和3维实体几何造型的基础上，研究液压集成块的3维参数化设计方法。在分析特征间关系模型的基础上，采用面向对象的设计方法，提出了对象化特征连接的概念，建立了液压集成块CAD环节中特征设计的关系模型。     

基于遗传因子理论的列车造型迭代设计方法

为满足列车设计升级需求，将遗传因子理论与轨道交通工具设计相结合，提出一种基于遗传因子理论的列车造型迭代设计方法。以某有轨电车造型设计为例，将列车造型分为侧视特征群和前视特征群，并运用造型分析法对其显性因子进行提取，将提取出的显性因子作为初始形状输入形状文法中，依据形状文法推演规则库和设计约束进行侧视和前视特征形状推演，从而生成下一代列车造型设计方案。通过实例验证了方法的可行性，可在较短周期内产生系列化列车造型设计方案，并在保持品牌形象识别的同时有效指导列车造型创新设计。     

天喻参数化三维设计平台

天喻CAD三维版是面向机械设计领域而设计开发的二、三维一体化产品造型和设计平台。具有强大的参数化特征造型、曲面造型功能和二维视图的自动生成能力,结合完整的二维图形系统,使用户不仅能得到精美的三维造型实体,而且能绘     

基于UG的宝马敞蓬车车身造型

提出了基于二维外形几何特征的宝马敞蓬轿车车身三维造型设计方法。利用UG软件中的插入模块获取车身的几何特征关键曲线,结合产品外形情况,进行三维建模和模型渲染,最后完成宝马敞蓬概念车的造型设计。该方法简化了设计过程,缩短了产品开发周期。     

计算机绘图技术的发展趋势

该文阐述了图纸扫描输入矢量化、图形参数化、工程图样识别，装配图与零件图一体化设计模型、三维特征造型以及比维图形可视化等方面的新进展，并提出了应用领域中急待研究解决的一些难点和热点问题。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...