整体涡轮大扭曲叶片电解精加工方法与试验研究

材料为高温合金的整体涡轮盘,其大扭曲叶片加工一直是制造业中的难题。提出多轴联动复合平面摆动展成电解方法加工大扭曲叶片,用一次进给电解实现叶盆、叶背面加工;分析复合平面摆动展成电解加工叶片型面成形规律,优化复合摆动展成电解加工数控编程及阴极结构设计,解决叶背出气边电解过切、根部三角区过切、出口短路等关键工艺问题;进行摆动式展成进给电解试验与分析,一次电解可达叶盆、叶背型面精加工要求。     

冷成形精密螺钉数值分析与工艺优化

利用有限元数值模拟仿真技术对精密微型螺钉的模具设计和成形工艺进行优化 ,对优化结果进行试验研究 ,并对成形缺陷进行金属学分析 ,讨论影响缺陷产生的因素 ,从理论上寻找缺陷产生的原因 ,从实践上印证理论分析和有限元模拟结果 ,最终得到可以消除裂纹和折叠缺陷的模具和工艺设计。     

蛋形耐压壳设计与分析

基于蛋壳几何学特性,开展了蛋形耐压壳结构设计与性能分析。根据鹅蛋形状扫描、宏观尺寸统计试验,研究蛋壳圆度、体积、表面积及蛋形系数分布规律,建立体积方程、表面积方程及蛋形函数;设计了4 km水深蛋形耐压壳,并定量分析其安全性、储备浮力、空间利用率、水动力学特性等性能;采用正交试验,研究长轴、短轴、厚度对蛋形耐压壳性能影响规律。结果表明,鹅蛋壳为高度对称结构,其蛋形系数符合均值为0.69的正态分布;蛋形耐压壳具有良好的综合性能,其中厚度是影响强度的重要因素,长轴次之,短轴最小;长轴是影响屈曲的重要因素,厚度次之,短轴最小;厚度是影响浮力系数重要因素,短轴次之,长轴影响最小;长轴是影响空间利用率的重要因素,短轴次之,厚度影响最小;水动力学特性主要受短轴影响。     

超声电解复合微细加工装置与试验研究

分析微细电解复合超声频振动加工过程机理,提出一种微细加工新方法--超声电解复合微细加工;设计、构造并完善复合微细加工装置;研究微细阴极制作工艺,利用微细组合电加工技术制作各类截面形状的微细阴极;进行超声电解复合微细加工试验,验证微细电解复合超声频振动实现微细加工的可行性及其在加工速度、精度、表面质量等方面的技术优势,探讨超声电解复合微细加工制作微结构的工艺规律。     

二元光学激光直写设备软件的再用技术

介绍了激光直写设备(LDWD)的软件系统的组成要求与特点.由于该设备的软件系统庞大而且复杂,由于开发周期长,开发人员多,使得此软件系统的开发与维护变得异常困难.本文提出采用软件组合技术,软件生成技术以及面向对象的程序设计技术,大大缩短了软件的开发周期与维护时间,同时使得系统的功能易于扩展.     

Modeling of Coriolis mass flow meter of a general plane-shape pipe

The vibration of a general plane tube with a flowing fluid, which is the measuring element in a Coriolis mass flow meter (CMF), is studied. The dynamic stiffness matrix method is used to model such a tube. The tube is divided into straight and circular elements. The elements dynamic stiffness matrices are derived from the equations of motion. By assembling the elements matrices into a global matrix the natural frequencies are obtained. The mode shapes are obtained by applying the boundary conditions at the supports and the compatibility conditions at the nodes. The effects of the flow velocity on the natural frequency and the relative phase difference are modeled. The method is applied to different tube shapes. The results are compared to the published data which reveals good agreement.     

Dynamic analysis of a rotating beam subjected to repeating axial and transverse forces for simulating a lathing process

The dynamics of the workpiece of a lathe is simulated in the presented paper. A rotating Rayleigh beam is chosen as a simple model of the workpiece. The beam or the workpiece is subjected to forces from the cutting tool of the lathe. The external forces, in transverse and axial directions, are traveling in a repeating or periodic motion. The force in the axial direction is a large cutting force resulting in coupled bending deformation while forces in the transverse directions are the contacting forces.In this paper, the governing equations of the rotating Rayleigh beam are derived by Hamilton's principle. The external, periodic forces resulted from the tool are expressed in Fourier series. Galerkin's method is then chosen for disceretizing the partial differential equations. The instability regions of the responses are determined by using the method of multiple scales and the Floquet theory. Fast Fourier transform gives the frequency domain responses for examining the dynamic characteristics. The numerical results are discussed. Parametric studies are also performed.     

Biped Robot with Triangle Configuration

A new biped robot with a triangle configuration is presented and it is a planar closed chain mechanism.The scalability of three sides of the triangle is realized by three actuated prismatic joints.The three vertexes of the triangle are centers of three passive revolute joints coincidently.The biped mechanism for straight walking is proposed and its walking principle and mobility are explained.The static stability and the height and span of one step are analyzed.Kinematic analysis is performed to plan the gaits of walking on an even floor and going upstairs.A prototype is developed and experiments are carried out to validate the straight walking gait.Two additional revolute joints are added to form a modified biped robot which can follow the instruction of turning around.The turning ability is verified by experiments.As a new member of biped robots,its triangle configuration is used to impart geometry knowledge.Because of its high stiffness,some potential applications are on the way.     

双梁门式起重机主梁结构计算机参数设计研究

论述双粱门式起重机参数绘图基本过程,给出了其绘图模块的编程思路,并对其主梁结构进行了全方位的规划,增加了一些特殊结构;编制了该软件程序并分析了其特点,并进行了优化分析。     

Dynamic analysis of rotating damped beams with an elastically restrained root

The vibration of a rotating damped blade with an elastically restrained root is investigated. The effects of viscous damping and the translational and rotational damping at the root of blade are considered. The flow-indued force and moment between the tip of a blade and the casing are simulated by using the time-dependent boundary conditions. A simple and efficient algorithm for deriving the semi-analytical steady state solution of the general system is proposed. The governing equation is divided into two coupled real differential equations. The two coupled equations are uncoupled into an eighth-order characteristic differential equation. The eight corresponding boundary conditions are obtained. The eight linearly independent homogenous semi-analytical solutions of the eighth-order characteristic differential equation are derived. If the coefficients of the uncoupled governing differential equation are constant, the exact fundamental solutions are obtained. The exact steady state solution is obtained by using Green's function in terms of the eight homogenous solutions. Moreover, the influence of the translational, rotational and viscous damping constants on the frequency response curves of a rotating beam are investigated. The opposite influence of the transverse viscous damping constant and the root damping constants on the frequency of resonance is revealed.     

基于蒙特卡罗法的气门弹簧稳健设计研究

以气门弹簧质量最小以及防共振性能最好为目标,以钢丝直径、弹簧直径、弹簧圈数为设计变量,以弹簧指数、弹簧强度、弹簧稳定性、弹簧尺寸等为约束条件,建立了某内燃机气门弹簧数学模型,并应用多岛遗传算法得到了全局优化结果。应用蒙特卡罗方法,将设计变量处理为具有正态分布特征的随机变量,对设计结果进行稳健性分析,研究设计变量变异对目标函数的影响。分析表明:在给定的精度下此设计结果不能保证气门弹簧的稳健性能。应用田口方法重新设计,提高了气门弹簧的稳健性能。     

主动红外热成像焊球缺陷检测方法研究

IC产品的小型化和多功能化使微电子封装密度不断提高,微焊球技术得以广泛应用,而微焊球尺寸和间距日益缩减,使隐藏于芯片或封装内部的微焊球缺陷检测变得十分困难。主动红外热成像技术被深入研究并应用于微焊球缺陷检测,构建了主动红外微焊球缺陷检测模型,并展开试验研究。对直径和间距较大的BGA焊球采用红外透射式测量法进行检测,对获得的热图像进行空间自适应滤波,然后通过边缘检测分割出焊球区域,减小了热噪声和焊球间隙噪声对缺陷识别的干扰,并通过有效热斑面积进行量化分析;对凸点直径和间距较小的FA10倒装芯片采用红外反射式测量法进行检测,利用改进的自适应滤波算法去除空间椒盐噪声,然后提取像素点温度序列值进行时间域移动平均降噪,并以指数形式进行曲线拟合,通过傅里叶变换进行时频转换,采用脉冲相位法解决了表面发射率差异引起的缺陷辨识度下降等问题,并使用低频段的相位信息进行表征分析。利用主动红外热成像技术实现了焊球缺陷的有效检测,为高密度IC封装及其可靠性分析提供了一种快速、有效的方法。     

The generation and properties of boundary films formed by diesel fuel at a steel/steel conjunction

Thin gel-like films are seen on the lubricated surfaces within diesel fuel injection equipment. The formation and properties of these films are investigated, under sliding conditions, using disc-on-plane machines; one steel has been used throughout. The development and maintenance of separation is measured by voltage drop and, during running-in to a high conjunction resistance, films are produced which are similar to those seen in practice. It is shown by static tests that separation is maintained by these films, which behave as quasi-elastic solids. The films are not miscible with diesel fuel and are not produced when the fuel is in static contact with the steel. They exhibit similar electrical properties under static and dynamic conditions: this was unexpected and is not yet understood. It is postulated that the films are produced by chemical reactions, and that the surface polishing observed is due to the same reactions     

Thermodynamic analysis of wide thrust bearings operating in laminar inertial flow regimes

Wide thrust bearings operating in laminar inertial flow regimes are studied. Isothermal and thermohydrodynamic performances of the bearing are analysed. Integro-differential equations of motion, continuity and energy equations are solved to yield pressure, mass-mean velocity and temperature distributions. The effects of contraction ratio and film Reynolds number on the pressure field, load bearing capacity, flow rate and frictional resistance force of the bearing are examined. The effect of film temperature variation on the performance of the bearing is studied and the result is compared with the isothermal case. Viscous heating is seen to reduce significantly the load bearing capacity. The effects of including the inertial terms are also considered. The results for inertial and non-inertial cases are plotted and compared. The results show that, with the inclusion of the inertial terms, the load bearing capacity does increase. Comparisons with some experimental data are made and reasonable agreement is observed.     

发动机叶片电解加工变间隙阴极修正法

为了提高叶片电解加工的精度,提出变间隙阴极修正方法,建立该方法数学模型,分析加工间隙与阴极修正量的对应关系,通过在型面误差中代入间隙补偿量来修正阴极。提出阴极沿型线修正量的计算公式和插值逼近的试验方法。结合自行研制的新型叶片电解加工机床,进行了叶片电解加工阴极修正的试验,通过变间隙修正方法修改阴极。试验过程中阴极经过3次计算机修正,可使叶片电解加工精度提高到0.05 mm,表明该阴极修正方法合理有效,数学模型与试验情况吻合。     

用量纲方法分析旋流场中的应力

在全面阐述旋流场应力的基础上,运用量纲分析比较的思想对旋流场中的应力作了分析比较。由分析可知在粘性应力中,切向和径向剪切应力占主导地位;而在湍流条件下,雷诺应力是粘性应力的若干倍数,此倍数在量级上即为雷诺数。由于各应力值的不同,故各应力在旋流场中的作用也各不相同。     

空气离心压缩机运转失效分析

介绍了5TYD160型空气压缩机运行失效的现象,分析出此压缩机使用环境中含有“SO2”气体和“铜尘”;水气分离器效果不好,轴套、冷却器壳体材料不防锈等是造成失效的原因,提出了改进措施.     

金相显微镜上实现三维微观形貌恢复

金相显微镜是一种经典的测量分析仪器,已经实现了金相显微镜图像的数字化采集,并恢复了三维微观形貌。首先,对金相显微镜的载物台加装电机,利用电机带动载物台进行精密移动,在载物台移动过程中,对被测物体等步距拍摄序列图像。然后,根据聚焦形貌恢复的原理,采用修正的拉普拉斯算子进行聚焦程度判断,利用高斯插值方法获取聚焦程度最大值以及此时被测表面的高度信息,恢复三维形貌。最后,利用金相显微镜对粗糙度样块进行测量,获得了相符的测量结果。该方法对于扩展金相显微镜的测量范围具有积极意义。     

The Distribution of Vibroshock Processes in Structures

The problem of calculating the one-dimensional vibration actuators of a simple structure with single inclusions as shock pairs is studied. A methodology for calculating such a system, which is based on the methods of the time-frequency analysis of vibroshock processes, is given. The corresponding motion equations are given along with their operator analogues and the consequent twoparameter representations of the periodic vibroshock processes. The durability is analyzed using the energy condition. There are representations that allow estimating the spectrum of the distributed vibration. The resonance states of vibration actuators with point inclusions as shock pairs are discussed. The calculation examples are given.     

Dynamic characteristics analysis and vibration experiment of Upper-time of Flight Counter (U-ToFC)

The dynamic characteristic parameters of Up-time of Flight Counter (U-ToFC) are important for research of structure optimization and reliability. However, the current simulation is performed based on homogenous material and simplified constraint model, the correct and reliability of results are difficult to be guaranteed. The finite element method based on identification of material parameters is proposed for this investigation on dynamic analysis, simulation and vibration experiment of the U-ToFC. The structure of the U-ToFC is complicated. Its’ outside is made of aluminum alloy and inside contains electronic components such as capacitors, resistors, inductors, and integrated circuits. The accurate material parameters of model are identified difficultly. Hence, the parameters identification tests are performed to obtain the material parameters of this structure. On the basis of the above parameters, the experiment and FEA are conducted to the U-ToFC. In terms of the flight acceptance test level, and two kinds of joints condition between the U-ToFC and fixture are considered. The natural frequencies, vibration shapes and the response of the power spectral density of the U-ToFC are obtained. The results show simulation which is based on parameters identification is similar with vibration experiment in natural frequencies and responses. The errors are less than 10% . The vibration modes of simulation and experiment are consistent. The paper provides a more reliable computing method for the dynamic characteristic analysis of large complicated structure.