对数螺旋锥齿轮接触分析

介绍了一种新型的螺旋锥齿轮—对数螺旋锥齿轮,该齿轮成功地将对数螺旋线应用为螺旋锥齿轮的齿向线,可以实现等螺旋角啮合。齿轮受载后的齿面接触区是衡量齿轮接触性能和传动质量的一个重要指标,将直接影响到齿面磨损及其使用寿命。采用有限元软件ABAQUS对对数螺旋锥齿轮进行动态接触分析,分析对数螺旋锥齿轮承受轻载和重载后的齿面接触区的形态及其变化规律,并与对滚实验的结果进行对比。得出对数螺旋锥齿轮的接触区承载后呈不规则椭圆形位于齿面中间偏小端,且随着载荷增大接触区在长度和宽度方向都有所增大。     

对数螺旋锥齿轮啮合仿真分析

建立对数螺旋锥齿轮的精确三维模型,应用ANSYS软件对对数螺旋锥齿轮啮合进行仿真分析.通过对不同啮合位置的对数螺旋锥齿轮进行非线性静态接触分析,得到啮合接触区域的应力变化规律,求解最大接触应力,并与理论分析结果进行比较.对对数螺旋锥齿轮的动态工作情况进行分析,得到对数螺旋锥齿轮在不同转速下不同啮合时刻的动态接触情况,比较转速对接触特性的影响.通过仿真分析,为对数螺旋锥齿轮的研究、设计与制造提供参考.     

相对位置误差对双重螺旋法加工齿轮副接触性能的影响

为预控双重螺旋法加工螺旋锥齿轮的啮合性能,研究了相对位置误差对双重螺旋法加工齿轮副接触性能的影响。根据螺旋锥齿轮副啮合接触原理,通过数值计算得到齿面离散啮合点分布位置,采用有限元法对不同相对位置误差条件下的齿轮副进行齿面啮合加载接触分析,得到了在不同相对位置误差条件下齿轮副传动误差、接触区位置及形状、法向接触力。结果表明,螺旋锥齿轮的传动误差和法向接触力均对小轮安装距误差较为敏感。通过滚检实验得到了齿面接触区位置和接触压力,验证了有限元分析结果。     

弧齿锥齿轮啮合过程动态应力分析

介绍了利用ANSYS对弧齿锥齿轮进行瞬态啮合的前置处理、划分网格、使加约束的方法。基于目前弧齿锥齿轮的应力分析研究现状。对齿面啮合质量进行了齿面接触分析(TCA),并且利用在CAE方面有很强能的ANSYS软件对弧齿锥齿轮进行啮合状态下的动态仿真[5-7],得到较为准确的齿面接触应力和齿根弯曲应力。建立了弧齿锥齿轮三维有限元非线性接触模型,对弧齿锥齿轮在一定的转速和负载转矩下进行了动态啮合仿真,得到了一个啮合周期下的齿轮齿面接触应力和齿根弯曲应力的变化规律。进行了轮齿加载接触分析(LTCA),得到了轮齿啮合传动中的齿面接触应力、弯曲应力变化过程。该方法可以进一步为弧齿锥齿轮强度分析和疲劳寿命计算提供理论依据。     

准双曲面齿轮研磨运动模型研究

分析准双曲面齿轮研磨原理,建立V/H与齿面啮合关系的数学模型。通过对齿面的接触印痕仿真与滚检试验。证明,所建之模型能对齿面研磨中研磨点的位置、移动方向、齿侧间隙进行准确的控制,为螺旋锥齿轮的研磨提供了理论指导。     

螺旋锥齿轮三维齿面接触分析研究

以往螺旋锥齿轮齿面接触分析过程中是通过二维齿面接触分析实现,为获得更直观齿面接触分析效果,采用数值法求得了螺旋锥齿轮三维齿面接触区。基于螺旋锥齿轮齿坯参数、刀具参数及安装调整参数建立螺旋锥齿轮数学模型,在此基础上建立螺旋锥齿轮虚拟装配数学模型,得到虚拟啮合的数学模型,采用数值法求解螺旋锥齿轮啮合过程中的接触迹线以及瞬时三维接触椭圆接触,最终得到螺旋锥齿轮齿面三维接触区。通过实际算例验证了相关算法的正确性。     

弧齿锥齿轮螺旋变性展成法切齿原理与仿真分析

传统加工方法加工弧齿锥齿轮副会使其接触区呈现对角线接触的不良现象,针对该现象,提出一种新型螺旋锥齿轮加工方法——螺旋变性展成法。为揭示螺旋变性展成法的切齿原理,根据机床、刀具和工件间的运动位置关系,以微分几何和齿轮啮合原理为基础,运用矢量分析法,以齿面中点为计算点建立切齿数学模型,分析推导机床调整参数计算公式;以一对弧齿锥齿轮为例进行了几何参数、刀具参数及机床调整参数的计算,建立弧齿锥齿轮三维虚拟仿真加工模型并进行齿面接触分析;最后,基于以上参数在数控铣齿机上进行切齿试验,齿面接触分析与滚检试验结果说明了螺旋变性展成法消除对角线接触的有效性。     

双圆弧弧齿锥齿轮齿面接触分析

齿面接触分析是双圆弧弧齿锥齿轮啮合分析的有效工具,是进行加载齿面接触分析、有限元分析的基础.文中利用齿面接触分析(Tooth Contact Analysis,TCA)原理,结合双圆弧弧齿锥齿轮的齿形特点,对其TCA程序的关键内容及实现方法进行了介绍,实现了对双圆弧弧齿锥齿轮传动啮合质量的数值仿真分析.最后通过实例对该TCA程序进行了验证,为双圆弧孤齿锥齿轮的设计提供了有效的手段和方法.     

螺旋锥齿轮的接触区及切齿机床的选用问题

螺旋锥齿轮副的接触区和齿面接触分析运动曲线是螺旋锥齿轮副重要的质量指标,影响螺旋锥齿轮的强度、寿命和啮合噪声。如何选用切齿机床和大、小轮的切齿方法以获得理想的接触区和齿面接触分析运动曲线是值得我们螺旋锥齿轮制造者关注的问题。     

弧齿锥齿轮准静态啮合仿真分析

利用大型有限元软件MSC.Marc,建立了弧齿锥齿轮副三齿啮合的三维有限元非线性接触模型.该模型可以实现转速和转矩的传递,基于该模型对齿轮副进行了准静态啮合仿真分析,并对啮合过程中的齿面接触应力及齿根弯曲应力变化规律进行了研究.数值计算结果符合弧齿锥齿轮的实际啮合规律,为进一步分析高速情况下弧齿锥齿轮的啮合状态提供了基础和依据.     

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.     

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。     

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.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

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...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.