Dynamic Simulation Analysis of the Flexible Swap Device

With the development of space science and technology,the on-orbit servicing technologies of spacecraft get more and more attention.According to the design criterion of existing spacecraft in orbit module replacement technology,the flexible swap device is designed and the dynamics simulation of institutions by the automatic dynamic analysis of mechanical systems(ADAMS)simulation software is analyzed.Throughout the analysis process,this paper studies the effect of collision force of flexible mechanism and provides a basis for the optimization of flexible plug agencies.

Dynamic Simulation of Mechanical System for Quickfeeding Shells in Gunboat4

A mechanical system for quickfeeding shells in gunboat is particularly analyzed from a dynamic view. SD nonlinear structural simulation is completed by means of dynamic explicit finite element method. Analysis results prove that the mechanical structure is feasible substantially, the material of outer surfaces near striking and overstress position should be improved and measures should be taken to avoid parts high temperature. And all analysis results give a principal theoretical basis for further work.

Dynamics analysis on transverse cutting mechanism of straw checkerboard paving robot

The transverse cutting mechanism of the checkerboard paving robot, which directly affects the robot＇s operation, is regarded as the most important part in a transverse pavement system This research aims at designing a new system which is appropriate for desert wofidng en- vironments and finishing cutting the rope of straw. In this paper, computer emulating technology is applied, and with three-dimensional modeling by Pro/ENGINEER software, can observe whether or not interference exists. Also, the speed and displacement parameters of the main parts of the cutting system are given by the dynamic emulation by Automatic Dynamic Analysis of Mechanical System （ADAMS）, which theoretically assures the feasibility and appropriateness of the cutting mechanisrn~ Finally, results of the experinaent shows that the cutting mechanism can cut the straw strand as designed.

KINETIC MODELLING AND PERFORMANCE ANALYSIS OF THE FOUR-POST-FRAME LIFTING MECHANICAL SYSTEM

The kinetic model of the four-post-frame lifting mechanical system was established. The stiffness and damping matrices of differential equations of motion were obtained by using Lagrange’s equations. And the dynamic characteristics of system were analyzed by modal analysis method. Based upon this, the modifications of structural parameters which can improve dynamic performance were discussed. The low-level high-speed palletizer MDJ1200L was taken as a real case in the paper.

Stochastic Response Analysis of Piled Offshore Platforms to Earthquake Load

In this paper, using the theory of stochastic analysis of the response to earthquake load, a stochastic analysis method of the response of piled platforms to earthquake load has been established. In the method, the strong ground motion is considered as three dimensional stationary white noise process and the pile-soil interaction and water-structure interaction are considered. The stochastic response of a typical platform to earthquake load has been computed with this method and the results compared with those obtained with the response spectrum analysis method. The comparison shows that the stochastic analysis method of the response of piled platforms to earthquake load is suitable for this kind of analysis.

Application of Grey System to Rock Dynamic Mechanics Field Under Blasting Loading

It is the key problem to be solved ror the development of Lagrange analysis bow to ase limited Lagrangian gauges and calculate the main information about the dynamic mechanical property of rock under blasting loading. This paper, using grey system, sets up a GM (1, 1 ) model relatal wltk characeristic time, and a theoretical analysis about tbe dynamic mechanical property has been carried out.The result of numerical simulation proves that the model is effective and feasible.

Integral Invariants of a Holonomic Dynamical System

This paper uses Poincare’s formalism to study . the integral invariants of aconservative holonomic dynamical system Introducing new parameters for theasynchronous variation, a generalization of the poincare and Poincare-Cartan integralinvariants is presented.

Analysis and Design of Thermally Actuated Micro-Cantilevers for High Frequency Vibrations Using Finite Element Method

Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations are considered: 1) a straight beam with two actuation layers on top and bottom which utilizes the bimorph effect to induce bending;2) a uniform beam with base excitation, where the beam is mounted on an actuator which moves it periodically at its base perpendicular to its axis. Generally, vibrating micro-cantilevers are required to oscillate at a specified frequency. In order to increase the efficiency of the system, and achieve deflections with low power consumption, geometrical features of the beams can be quantified so that the required vibrating frequency matches the natural frequencies of the beam. A parametric modal analysis is conducted on two configurations of micro-cantilever and the first natural frequency of the cantilevers as a function of geometrical parameters is extracted. To evaluate vibrational behavior and thermo-mechanical efficiency of micro-cantilevers as a function of their geometrical parameters and input power, a case study with a specified vibrating frequency is considered. Due to significant complexities in the loading conditions and thermo-mechanical behavior, this task can only be tackled via numerical methods. Selecting the geometrical parameters in order to induce resonance at the nominal frequency, non-linear time-history (transient) thermo-mechanical finite element analysis (using ANSYS) is run on each configuration to study its response to the periodic heating input. Approaches to improve the effectiveness of actuators in each configuration based on their implementation are investigated.

智能挂弹机器人结构设计与举升机构仿真分析

针对目前军用机场传统液压挂弹系统作业时间长、人力成本高、挂载精度低等问题,设计一种智能挂弹机器人以提高挂弹作业效率.首先,完成智能挂弹机器人的机械结构总体设计;其次,对智能挂弹机器人最关键的举升机构进行静力学和运动学分析,建立起举升机构力矩平衡方程和运动学方程;最后,通过机械系统动力学自动分析(automatic dynamic analysis of mechanical systems, ADAMS)仿真计算举升机构在作业过程中的推力变化和末端托盘速度变化情况.实验结果表明,所设计的举升机构性能达到了预期要求,同时仿真结果也可为智能挂弹机器人的举升电力系统设计和选型提供可靠的数据支持.

考虑磨损故障的双渐开线齿轮传动系统动态特性研究

针对目前双渐开线齿轮(DIG)研究过程中齿廓磨损对双渐开线齿轮动态特性的影响问题,对考虑磨损故障的双渐开线齿轮传动系统动态特性进行了研究。首先,进行了双渐开线齿轮接触线长度与齿面载荷计算,考虑相对滑移距离,建立了等效接触模型;然后,进行了双渐开线齿轮齿面累积磨损量、齿轮齿面累积磨损深度的计算,建立了双渐开线齿轮啮合刚度计算模型,进行了磨损故障的双渐开线齿轮刚度的计算;最后,以一对双渐开线齿轮为研究对象,采用集中质量法建立了6自由度动力学模型,研究了齿面磨损对双渐开线齿轮动力学特性的影响。研究结果表明:在运行1×104次载荷循环后,混合弹流润滑状态下,双渐开线齿轮与普通渐开线齿轮(CIG)在节线附近齿根位置的最大累计磨损量差值为0.00207μm,且双渐开线齿轮节线靠近齿顶位置的磨损小于普通渐开线齿轮的磨损;双渐开线齿轮系统在磨损后振动加速度幅值小于普通渐开线斜齿轮的幅值。通过对不同磨损情况下的时域响应进行研究,发现磨损导致双渐开线齿轮传动系统的振动幅值增大。

基于演化博弈的智慧建筑发展机制研究

为促进建筑业转型升级、推进智慧建筑发展,构建地方政府和开发商演化博弈模型,基于博弈理论和系统动力学,在静态与动态双重机制下,应用vensim软件仿真分析,分析双方行为策略。仿真结果表明:静态机制下,地方政府和开发商行为策略是不稳定的,系统是不稳定均衡状态;动态机制时,系统收敛并达到稳定均衡。政府应该完善惩罚机制、设置合理补贴,同时与企业合作,共同推进我国智慧建筑可持续性健康发展。

静态推靠式旋转导向系统偏置机构导向力仿真与分析

介绍了静态推靠式旋转导向系统的结构和工作原理,建立了旋转导向钻井工具的力学模型,得到了钻头处挠度和转角在导向合力作用下的计算式及工作状态下导向工具偏置导向合力与钻头处导向力之间的关系;利用三维建模软件SolidWorks建立了静态推靠式旋转导向钻井工具的三维模型,在ADAMS软件中建立有限元仿真模型,进行仿真后得到钻头处导向合力在工具面角、偏置导向合力等影响作用下的变化曲线关系,对比了在导向合力作用下钻头和翼肋处的偏置量与钻头转角的计算值与仿真值,验证了推导的力学模型中钻头转角和挠度曲线公式的正确性,理论计算值与ADAMS仿真数值解较为接近。在推导的芯轴的变形和钻头转角的基础下,若已知造斜率可以反向推导计算出所需要的导向合力,进而可以分解出3个翼肋上分力的大小即可以通过调控每个导向翼肋上的液压力来更加精确、实时地控制井眼轨迹,为静态推靠式旋转导向系统的偏置机构程序控制开发奠定基础。

Improved Design and Dynamic Characteristics Research for Printing Machinery

Rotational stability of embossing roller is a key technical specification for the printing machinery,and conjugate cam is the important control of the main driving system.In order to enhance the rotational stability,the improved design of conjugate cam is made to meet the quintic polynomial equation of the mathematical model,replacing the original cosine cam in the printing machinery.Aided with simulation Automatic Dynamic Analysis of Mechanical Systems(ADAMS)software,the whole mechanical system model is built and dynamic simulation is carried for the two driving systems(the improved and the original).The key component's dynamic characteristics,especially contact force's change and influence are studied and the kinetic characteristics of the two systems,are analyzed and compared,which proves the improved system more stable in rotation.

滚-跳多运动模式球形机器人的动力学仿真研究

复杂的探索环境对探测机器人的通行能力提出了更高要求,具有多种运动模式的球形机器人是探测机器人领域的研究热点之一。通过对球形机器人内部构件质量分布的调节,设计了一种基于单摆驱动式的滚-跳多运动模式球形机器人,其具有滚动、转向、爬坡与跳跃4种基本运动能力;随后,又根据球形机器人的设计方案建立了球形机器人4种基本运动动力学方程。利用Automatic Dynamics Analysis of Mechanical Systems(ADAMS)软件构建该球形机器人虚拟样机并对其进行了滚动、转向、爬坡与跳跃的动力学仿真,最后以此为依据计算滚动、转向、爬坡与跳跃运动性能的仿真值,并制作实验室样机验证了动力学仿真的正确性。

进近管制运行风险动力学演变机理与控制研究

为探究进近管制风险形成及演化机理,科学制定风险控制策略,从网络化视角构建系统动力学模型分析风险演变与控制策略。首先,利用过程识别理论将风险分为主动控制失效和反馈控制失效,从动力学视角分析致因间作用机制;然后,构建系统动力学模型与动力学方程;最后,给出风险致因对风险水平影响机理和控制策略。结果表明:扇区超容、同时指挥航空器数量增加、协作效率低是风险演变核心因素;在单一策略中调整流量时空分布最有效;组合策略中调整流量时空分布系数同时优化交叉点结构效果具有叠加性,比单一策略可进一步降低54%运行风险;调整流量时空分布与增加可调配空域具有替代性;完善监控体系与提升人机熟悉度组合策略效果具有1~2月时滞性。

基于动态模态分解的输电杆塔松动检测

为了识别输电杆塔的松动状态,提出分段高阶动态模态分解(segment high-order dynamic mode decomposition,SHDMD)的检测方法。为减小振动耦合对检测的影响,利用三轴加速度和三轴角速度构造时间-空间矩阵,从中提取准确的方向振型作为松动特征,将时间-空间矩阵在时间维度上划分为若干子矩阵,对每个子矩阵进行空间维度扩展,避免DMD分解时得到错误结果,对扩展后的子矩阵进行DMD分解,得到不同时段的振动模态,利用稳定图筛选出不同时段共有的模态作为真实模态,提取与模态一一对应的方向振型。建立灰色关联检测模型,通过计算方向振型的几何特征关联度,识别当前松动状态。模拟杆塔试验与真实杆塔试验结果证明,所提方法能够很好地实现输电杆塔松动位置与松动程度的识别。

Oxidation Kinetics of Aluminum Powders in a Gas Fluidized Bed Reactor in the Potential Application of Surge Arresting Materials

In this technical paper, the oxidation mechanism and kinetics of aluminum powders are discussed in great details. The potential applications of spherical aluminum powders after oxidation to be part of the surging arresting materials are discussed. Theoretical calculations of oxidation of spherical aluminum powders in a typical gas fluidization bed are demonstrated. Computer software written by the author is used to carry out the basic calculations of important parameters of a gas fluidization bed at different temperatures. A mathematical model of the dynamic system in a gas fluidization bed is developed and the analytical solution is obtained. The mathematical model can be used to estimate aluminum oxide thickness at a defined temperature. The mathematical model created in this study is evaluated and confirmed consistently with the experimental results on a gas fluidization bed. Detail technical discussion of the oxidation mechanism of aluminum is carried out. The mathematical deviations of the mathematical modeling have demonstrated in great details. This mathematical model developed in this study and validated with experimental results can bring a great value for the quantitative analysis of a gas fluidization bed in general from a theoretical point of view. It can be applied for the oxidation not only for aluminum spherical powders, but also for other spherical metal powders. The mathematical model developed can further enhance the applications of gas fluidization technology. In addition to the development of mathematical modeling of a gas fluidization bed reactor, the formation of oxide film through diffusion on both planar and spherical aluminum surfaces is analyzed through a thorough mathematical deviation using diffusion theory and Laplace transformation. The dominant defects and their impact to oxidation of aluminum are also discussed in detail. The well-controlled oxidation film on spherical metal powders such as aluminum and other metal spherical powders can potentially become an important part of switch devices of surge arresting materials, in general.

复杂载荷下大柔性多臂节机械臂架系统刚柔耦合动力学分析

为更加准确地研究复杂载荷下大柔性、多臂节机械臂架系统的动力学特性,提出基于刚柔耦合特性对臂架系统进行动力学仿真分析的方法。首先,根据臂架系统及部件的实际尺寸建立三维模型,并将臂架系统中弹性变形较大的转台,三、四、五节臂架考虑成柔性体;然后,在ANSYS WorkBench中建立臂架系统的刚柔耦合模型并进行仿真分析;最后,通过分析得到关键柔性体部件铰点的载荷受力曲线与臂架系统中柔性体部件的应力云图。分析结果表明:大柔性、多臂节机械臂架系统在设计中考虑柔性体因素进行刚柔耦合分析与工程实际更加相符,也可以更好地为臂架系统的改进与结构优化奠定基础。

考虑扣件系统非线性力学行为的车辆与轨道动力分析模型

为深入研究扣件系统的力学特性及其损伤失效对轮轨系统振动的影响,基于精细的扣件系统有限元模型揭示扣件弹条扣压状态和轨下胶垫支承状态的非线性力学特征,提出并建立考虑扣件系统非线性力学行为的车辆与轨道动力分析模型。通过实测结果验证本文模型的计算可靠性,并分析扣件失效类型对轮轨系统动力响应特性的影响。研究结果表明:弹条扣压力随弹程增大而近似呈双线性特征,单个弹条扣压刚度在“2点接触”状态时为0.675 kN/mm,在“3点接触”状态时为5.11 kN/mm;本文模型计算得到的钢轨加速度响应频率100 Hz以上的较传统模型明显增大,与实际情况更为接近;传统模型利用刚度属性折减或去掉弹簧单元来实现扣件弹条失效的模拟,会放大失效区域附近的轮轨系统动力响应;针对扣件失效的情况,包括弹条失效和胶垫失效,实际现场运营维护时不仅要关注失效区域内的轨道结构状态,对于后邻近区域也要及时加强关注。

进给系统角接触球轴承的热力耦合分析

对角接触球轴承热力耦合性能进行预测分析是保证机床工作精度的关键。基于赫兹接触理论结合热网络方法,建立滚珠丝杠进给系统成对安装轴承工作状态下的动态热力耦合模型,考虑了温升热效应下的球轴承内部润滑状态以及热膨胀,提出了轴承的动态热力耦合分析数值计算方法。探明了轴承内部接触参数和摩擦生热的时变规律。研究表明:转速、外部载荷等工况影响轴承的摩擦接触特性,轴承性能显著受热力学行为的影响。提出的轴承动态热力耦合分析模型可以有效预测轴承非线性热行为下的接触特性。