单螺杆压缩机星轮的有限元模态分析

应用SolidWorks软件建立了单螺杆压缩机星轮的三维实体模型,利用ANASYS对星轮进行了有限元模态分析,得到了星轮前6阶固有频率及其对应的振型,并对低阶固有振型进行归纳。这些结果可为单螺杆压缩机星轮的动态设计提供参考。     

空间共轭啮合副二次包络面三面共点构造法

关于空间共轭啮合副二次包络面的设计问题,尚没有一个完整而普遍的设计方法。基于此,在连续滑动接触和共轭啮合的基础上,提出一种空间共轭啮合副二次包络型面的三面共点构造法,并详细叙述二次包络面族的生成原理和两个辅助平面族的构造方法,给出求解这三类面的交点的图解法和解析法以及三面共点构造法的设计步骤和应用领域。应用三面共点构造法研究单螺杆压缩机啮合副的关键技术时,针对单螺杆压缩机共轭啮合副的热点问题提出五论一没有的观点。同时结合双椭圆产形面二次包络型线单螺杆压缩机的设计实例,得出整体星轮将取代浮动星轮,金属星轮将取代非金属星轮,应用多轴联动机床加工单螺杆啮合副是未来单螺杆压缩机和单螺杆膨胀机啮合副加工和生产的发展方向的结论。     

星轮的模态分析和疲劳分析

应用Ungraphics（UG）软件建立了单螺杆压缩机星轮的实体模型,利用ANSYS软件对星轮进行有限元模态分析,采用BLOCK LANCZOS方法进行模态计算,得到了星轮在固定约束下的前6阶固有频率及其对应的振型。使用兰德格拉夫损伤公式计算出了星轮疲劳寿命为1．60年。这些结果对星轮的设计、制造及维修有重要意义。     

单螺杆压缩机环面蜗杆——星轮制造专机问世

上海飞和实业集团有限公司积30余年单螺杆压缩机制造经验，经过几年的努力，在直廓环面蜗杆一星轮的制造检测技术上有了重大的突破，研制过程利用计算机技术模拟了滚切星轮的全过程，设计制造出高精度数控蜗杆一星轮加工专机。     

单螺杆压缩机星轮与螺杆啮合位置的误差分析

通过对单螺杆压缩机核心部件——星轮与螺杆啮合位置进行误差分析,从而为啮合副型线设计、星轮与螺杆加工专机的设计及加工工艺方法等一系列技术工作,提供有效的理论论据.     

单螺杆压缩机星轮的周向力分析

星轮磨损速度快,使机器容积效率下降迅速,是单螺杆压缩机发展的主要技术障碍。对大量失效星轮的齿面检测结果表明：星轮齿前侧的磨损比齿后侧严重。这与当前技术文献所持观点不符,且刚好相反。对气体力作用在星轮上形成的周向力进行了分析,结果表明该周向力扭矩是导致星轮齿快速磨损,且齿前侧易于齿后侧磨损的根本原因。对星轮齿的磨损行为进行了定性分析,并提出在星轮前、齿后侧分别采用不同的型线以减小周向力矩,提高星轮寿命。     

单螺杆压缩机几何参数对压缩机性能的影响

根据单螺杆压缩机的结构特点和工作过程特性,分析了单螺杆压缩机中啮合副的几何参数对压缩机性能的影响。计算了不同中心距系数和星轮螺杆直径比情况下压缩机的排气量,排气孔口位置和面积以及在排气孔口位置保持不变的情况下的流动损失情况。通过分析发现:排气量随星轮螺杆直径比的增大而增大,而随中心距系数的增大呈先增大后减小的趋势。排气开始位置不受星轮螺杆直径比变化的影响,只随中心距系数的增大而往排气侧延迟,排气孔口面积则随星轮螺杆直径比的增大而增大。在排气孔口位置不变的情况下,随星轮螺杆直径比增大,排气过程的流动阻力损失线性增加。该分析结果为压缩机改型设计提供了依据。     

单螺杆压缩机螺旋啮合副加工技术研究

随着单螺杆压缩机的发展,对啮合副的型线及螺杆的加工精度也就有了更高的要求.文中介绍在五轴机床上利用棒铣刀加工螺杆的方法,制造出单螺杆压缩机的一次包络关键螺旋零件-转子螺杆.以此螺杆生成的一次包络曲面为基础,利用一种特殊的方法二次包络成型出单螺杆压缩机的另一个关键部件-星轮.由于星轮是由螺杆挤压成型,所以在理论上星轮可以和螺杆完全啮合.     

单螺杆压缩机的进展与突破

介绍单螺杆压缩机的进展情况。提出了用“铣刀”替代星轮滚刀的方法。在没有理论误差的前提下，使切削力减至８％以下，刀具寿命提高１０倍以上，使大批量生产优质星轮成为可能     

单螺杆压缩机星轮的制造技术

从分析单螺杆压缩机啮合副的动态啮合过程入手，研究了星轮滚刀的切削过程并加以改进，终于解决了高精度星轮滚刀的制造困难。与长滚刀相比，改进后的“铣刀”的切削力小９０呢以上，使用寿命提高１０倍以上。     

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.     

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.     

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.     

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。     

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.     

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.