薄膜节流六腔静压轴承的设计计算

对静压轴承作了一般性介绍,提出了静压轴承的设计准则。通过双薄膜节流六油腔静压轴承的设计实例,演释了静压轴承设计的通用模式;实例的结果验证了设计方法是科学的、有效的、正确的,为磨床砂轮架静压轴承设计打开了一个新的思路。     

基于有限元气体静压主轴模态分析

为了分析气体静压主轴的动态性能,研究气体静压主轴的设计合理性和高速稳定性,建立了气体静压轴承刚度的模型,应用FLUENT对气体静压轴承进行了流体分析,计算出了气体静压轴承的支撑刚度。在此基础上应用ANSYS Workbench对气体静压主轴进行模态分析,得到了气体静压主轴的各阶固有频率以及其相应振型。分析结果表明了气体静压主轴的共振频率随着轴承刚度的增加而增加,引起气体静压主轴的临界速度远远大于设计的最高速度,说明气体静压主轴设计是合理可靠的。     

层流液体动静压混合轴承设计理论研究

分析并总结了液体动静压混合轴承的静压补偿原理，层流液体动静压混合轴承的设计要求，并建立了求解层流液体动静压混合轴承的基本方程。     

液体静压轴承对经纬仪精度影响的分析

在大刑经纬仪垂直轴中采用液体静压轴承是一个尝试.由于在仪器设计中采用了结构合理的液体静压轴承,高刚度的薄膜反馈及螺旋沟式阻尼器, 使经纬仪轴系精度大大提高.本文分析了液体静压轴承影响经纬仪精度的各种因素, 推导了数学分析式,提出了“抹平效应”的概念, 对采用大型滚动轴承和静压轴承的几种经纬仪的有关精度指标进行了比较.结果说明,采用静压轴承的精度高, 因而,在大型高精度经纬仪设计中采用液体静压轴承是有利的.     

恒流供油扇形静压推力轴承承载力解析计算与实验研究

针对重型液体静压转台的传统设计中,恒流供油扇形静压推力轴承承载力的计算未计入离心力因素,且传统设计使用的简化计算方法缺乏实验验证的问题,推导了计入离心力因素的恒流供油扇形静压推力轴承承载力解析计算公式;设计建立了重型液体静压转台实验系统,并进行了实验研究。实验值与解析计算值的对比分析表明,两者基本吻合,验证了计入离心力因素的恒流供油扇形静压推力轴承承载力解析计算公式有效可行,为恒流供油扇形静压推力轴承的设计计算提供了理论依据。     

M115W外圆磨床磨头液体静压轴承改装设计

不等封油边静压轴承,利用主轴挠度对轴承油膜刚度的影响,变主轴挠度这个不利因素为提高轴承油膜刚度的有利因素.因此,不等封油边静压轴承的设计,是在固定节流静压轴承的基础上,通过改善轴承本身结构提高轴承的承载能力.M115W外圆磨床磨头采用不等封油边液体静压轴承进行改装设计,提高了主轴系统的刚度,改装后的M115W外圆磨床达到了原有的加工精度和使用性能.     

胀套在精密离心机上的应用

针对精密离心机静压气体轴承这一高精度回转支撑,介绍了静压气体轴承与转盘间采用胀套连接的新方式。基于精密离心机静压气体轴连接特性要求,进行了胀套选型。针对所选型号,开展了胀套额定安装条件对静压气体轴承结构的影响数值模拟分析,发现了安全隐患。结合静压气体轴承内压对自身结构的影响数值模拟分析和静压气体轴承结构变形特殊要求,计算获得了合适的胀套安装技术要求。本连接方法及设计在某精密离心机上得到了应用验证,可供相关设计应用参考。     

基于ANSYS 12.0的静压轴承双向流固耦合分析

静压轴承油膜承载能力的设计和轴承材料的选择对静压轴承的工作性能和使用寿命显得尤为重要。应用ANSYS 12.0软件Workbench,ANSYS Mechanical和CFX的流固耦合功能对某大型球磨机静压轴承进行双向流固耦合分析,校核静压轴承油膜的承载能力和轴承材料的结构强度。     

高速轧辊磨床主轴系统动静压轴承供油液压系统的开发

介绍了普通轧辊磨床主轴系统动静压轴承供油方式的特点,并对常用的普通动静压轴承的恒流量供油系统和恒压供油系统进行了详细的对比分析,在此基础上,设计了高速轧辊磨床主轴系统动静压轴承的供油液压系统,结果表明,相较于常用的普通动静压轴承的恒压供油系统,高速动静压轴承的恒压供油系统的压力稳定性更好,压力调节更方便和可靠.     

精密磨床转台静压轴承的强健化设计

针对精密磨床转台静压轴承性能仿真数据与其回转精度实测数据不一致的问题，为提高转台静压轴承的设计水平，提出了静压轴承的强健化设计方法。该方法考虑了轴承结构参数在轴承全生命周期内的变化，分析了半径间隙、油腔尺寸、节流比及润滑油黏度在设计、加工、装配和服役4个阶段的变化规律，重点研究了半径间隙在各阶段对轴承性能造成的影响，给出了转台静压轴承的强健化设计流程。通过一个径向轴承的设计实例对该强健化设计方法进行了说明，并将设计结果与传统设计进行了对比。对比的指标是轴承在4个阶段的刚度、承载力和温升，这3个指标对轴承回转精度有直接影响。研究表明：进行强健化设计后，在生命周期内静压轴承的刚度和承载力的变化量为10%~27%，温度的变化量为0.5%~1.6%，较传统设计更能保证转台回转精度的稳定。     

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...     

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。     

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。     

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.     

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.     

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.     

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...