汽轮机叶片CAD/CAM软件开发

由于通用CAD/CAM软件存在难以实现汽轮机叶片参数化三维建模,在变轴加工过程中不能进行变前倾角、变侧倾角加工和拐角减速等问题,开发了汽轮机叶片CAD/CAM软件.软件通过研究汽轮机叶片各曲面特征建模方法,实现叶片零件参数化建模;通过研究刀具轨迹计算公式,设置叶片各曲面段不同工艺参数,获得了叶片粗加工、螺旋精加工和清根加工的变参数轨迹规划方法,并解决了以上问题.     

基于MATLAB与UG的汽轮机叶片造型及数控编程研究

将测量的叶片截面数据经Matlab软件平滑处理,再将平滑处理后的数据导入UG,基于UG软件的强大建模功能和曲面编辑功能,采用NURBS方法建立汽轮机叶片的空间样条曲线,对叶片进行了几何造型;在CAD模型的基础上,进行了叶片的数控加工工艺流程规划,并用软件的CAM功能对叶片进行了数控加工仿真。     

汽轮机动叶片叶型数控编程研究与设计

汽轮机动叶片的叶型是一种具有代表性的复杂曲面零件。针对叶身型面进行点三维数据采集,采用某一段程序数据结合软件,构造了汽轮机动叶片叶身部分某一截面;再采用全部数据代用曲面混合的参数化建模方法对叶型进行三维实体造型。由此通过CAM的功能对叶片进行数控加工仿真加工研究,巧妙的设计工艺参数,生成合理的NC代码。在叶片的参数化设计和加工处于不同软件环境下,使数控仿真加工的质量和效率不受环境的影响,从编程设计阶段保证数控加工程序的正确,具有一定的指导意义。     

汽轮机叶片的结构特点与数控加工技术研究

本文对汽轮机叶片的结构特点作了分析,介绍了汽轮机叶片CAD/CAM技术工作流程,分析了汽轮机叶片的数控加工工艺,探讨了汽轮机叶片数控加工编程技术.     

汽轮发电机风叶叶片的数控模拟加工

针对实际生产问题深入分析汽轮机风叶结构特征,选择UG/CAD的建模技术为风叶建立数字化模型,利用CAD/CAM软件Mastercam对其进行了多轴联动数控加工程序的编制,完成风叶叶片多轴加工工艺路径规划和汽轮机风叶叶片四坐标数控加工动态仿真,实现了汽轮机叶片的虚拟加工。通过对数控加工程序的质量检查、仿真结果的分析,将过切与干涉等不安全因素消除,确保数控加工程序的正确性,优化工艺、提高生产效率。     

基于NURBS的汽轮机叶片数控加工仿真分析

汽轮机叶片形状复杂,其表面为扭曲的变截面曲面,对汽轮机叶片进行精确的几何造型及数控加工对保证叶片加工质量十分重要。基于NURBS建模理论,借助MATLAB软件建立了汽轮机叶片的几何模型,利用UG软件对生成的汽轮机叶片进行了数控加工轨迹生成和仿真分析。结果表明该方法可以有效地对叶片进行加工处理,对工业生产具有一定的指导作用。     

复杂曲面的逆向造型设计及多轴联动加工

基于逆向工程技术及CAD/CAM技术的平台,针对某一工艺品的点云模型文件,利用逆向工程软件Geomagic完成复杂曲面的NURBS曲面三维造型并进行误差分析。根据该复杂曲面零件的结构特点,合理制定加工工艺,运用UG软件生成多轴加工刀具轨迹及数控加工代码。最终经Vericut软件构建的双摆台五轴机床验证了数控程序的正确性。研究表明,利用逆向造型软件对复杂曲面产品进行NURBS曲面重构,结合CAD/CAM技术,不仅能高效地对复杂曲面产品进行二次设计,从而大大缩短产品开发周期,而且也能为复杂曲面零件的仿制加工提供依据。     

基于DXF文件的NC代码生成

论述了CAD CAM软件一种常用图形交换文件 (DXF文件 )的结构和基于DXF文件平面数控加工的NC代码生成软件的接口技术、总体框架设计及NURBS曲线分析和NC代码生成。     

基于UG的汽轮机叶片CAD/CAM系统开发研究

对汽轮机叶片型面特征及加工方法进行了分析,在UG环境下利用二次开发工具和VC 语言,进行了汽轮机叶片CAD/CAM系统的开发研究,所开发完成的软件系统能够根据用户输入的叶片原始参数,自动生成叶片三维数据模型,并通过其CAM模块自动进行叶片砂带磨削NC程序的编制.     

UG NX5软件在三轴数控铣床中的开发利用

通用的UG NX5 CAD/CAM软件的功能虽然能满足工作中大部分需求,但是,许多专业问题解决起来比较困难.文中通过UG NX5软件平台,二次开发了利用三轴数控铣床,加工汽轮机叶片叶根、叶冠内背弧圆角等工序程序,与通用的CAD/CAM软件集成,使之成为一个高效、易用的应用系统.     

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...     

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.     

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。     

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...     

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。     

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。     

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.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

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.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.