分析动力学

The variable geometry truss mechanisms have been studied extensively and systematically by this project. The research plan has been completed all sidedly, and expected results have been obtained. Three new kinds of combination decahedrons and a new class of variable geometry truss mechanism, which is composed of an octahedron and three tetrahedrons connected in parallel form, are proposed. The position analyses for decahedrons, dodecahedrons, triple-octahedrons, combinations decahedron and a new type of structure of variable geometry truss mechanisms are presented by introducing additional extra linear displacement sensors and using resultant elimination and homotopy continuation algorithms. The method of kinematical analysis of variable geometry truss mechanisms is established.

课题组对变几何桁架机构进行了深入的研究，全面地完成了研究计划，取得了预期的成果；提出了三种新的十面体组合机构以及由一个八面体和三个四面体组成的新型变几何桁架机构的结构形式；应用结式消元、附加传感器和同伦方法等提出了十面体、十二面体、三重八面体、组合十面体和新型变几何桁架机构的位置分析方法；建立了变几何桁架机构运动分析的一般方法；建立了简洁的凯恩和拉格伦日动力学的模型；应用有限元和子结构方法，提出了变几何柞架机构弹性动力学模型，导出了逆动力学方程的显式形式；设计和研制了一台可折叠的八面体变几何杵架机构装置等。

The main work and results are as follows:(1) According to the particular movement of high spot closed gripper mechanism, the full method of dynamic characteristics was presented and built. It contained relative motion analysis, absolute motion analysis, dynamics of rigid body's analysis and elastodynamics analysis.

本论文主要工作和取得的成效如下：(1)针对高点闭牙机构运动的特殊性，提出并建立了机构动力特性分析方法，包括相对运动分析、绝对运动分析、刚体动力学分析和弹性动力学分析。

This model is different from the structural dynamics model in a non-inertial reference frame with large overall motions known.

本文从力学基本原理出发，分析了刚柔耦合零次近似理论失效的原因，深入研究了有大范围运动的柔性体变形场的描述，建立了刚柔耦合一次近似的动力学模型；然后利用上述模型，从非惯性系下的结构动力学问题和大范围运动为自由的刚柔耦合动力学问题这两个层次上进行了刚柔耦合动力学建模理论与性态的研究，采用理论和实验相结合的手段来检验了一次近似刚柔耦合动力学模型的正确性。

Based on the single-axis air-bearing test bed, three experiment schemes are creatively designed for investigating the behaviors of rigid-flexible coupling dynamics:(1) experiment scheme for structural dynamics problem under a non-inertial frame,(2) experiment scheme for rigid-flexible coupling dynamics with unknown large overall motions,(3) experiment scheme for modal analysis of a typical rigid-flexible coupling system.

为了能更深入地揭示刚柔耦合动力学特性与验证本文提出的一次近似模型的正确性，最后重点介绍了我们在单轴气浮台动力学仿真实验平台基础上，经过多次探索和总结，创造性地设计的三套刚柔耦合动力学实验方案：(1)非惯性系下结构动力学问题的实验研究方案，(2)大范围运动为自由的刚柔耦合动力学问题的实验研究方案，(3)刚柔耦合系统模态分析实验方案。这三套方案从实验的角度来讲是可行的，这为下一步的实验工作打下了基础。

The efficiency of an closed epicyclic gear train is analyzed by means of this formula, some of efficient curves are drawn, and an adequate selecting range of transmission ratio is found.

推导出了动力学模型中惯性元件、弹性元件和分支节点的动力学分析的数学模型，用传递矩阵法建立起封闭周转轮系动力学分析的数学模型。

With ADAMS,a kind of dynamics analysis software,a dynamics model of vehicle with leaf spring and another with hydropneumatic spring were set up.

利用动力学分析软件ADAMS，建立了钢板弹簧车辆和油气弹簧车辆的动力学模型，开展了整车在随机路面上的平顺性仿真，分析了两种悬架对车辆平顺性的影响，并通过仿真数据与试验数据的对比，验证了动力学模型的正确性

The microstructure evolution and composition distribution of the 7A55 cast and homogenized alloy were studied by optical microscopy, scanning electron microcopy, energy dispersive spectrometer, transmission electron microscopy and X-ray diffractometry. The homogenizing and overburnt temperatures of the alloy were determined. Meanwhile, the diffusion kinetics of the alloy elements during homogenizing treatment was investigated and the homogenizing kinetic equation was deduced according to Fick's First Law of diffusion. The diffusion of alloy elements, precipitation of Al3Zr particles and the conglomeration and globe of the insoluble phases were explained by the equation during homogenization.

摘 要：采用光学显微镜、扫描电镜、能谱分析、透射电镜和X射线衍射分析等研究了7A55合金铸态与均匀化显微组织演化与成分分布，确定了该合金的均匀化处理温度与过烧温度，研究了铸锭均匀化动力学过程，利用菲克定理导出了均匀化动力学方程，利用动力学方程对均匀化过程中合金元素的扩散、 Al3Zr的析出、难熔相的聚集和球化现象进行了解释。

We review domestic and abroad research progresses of epilepsy by nonlinear dynamical theory and method, which include dynamical interpretation of epileptic pathogenesis, analysis of dynamical characteristic quantity of EEG signals during interictal and ictal stage, foundation of prediction mechanism and system.

我们综述了国内外采用非线性动力学的理论和方法对神经科癫痫研究的进展，包括发病机理的动力学解释，发作间期和发作期脑电图信号的动力学特征量的分析，以及预报机制的建立等；同时介绍了最近本课题组采用建模分析的方法研究癫痫脑电的主要结果，以及对癫痫发作过程的动力学性态变化规律的若干新发现；据此提出了研究中的一些问题和设想。

Initially, assuming that the contact between cam and tappet is"dry contart", a dynamics model of Hertzin contact stiffness and impact damping is established. Next, with dynamic load on cam—tappet pair from the model, an analysis is made both to unsteady EHD oil film in cam—tappet pair under condition of full and partial lubrtication and to wear characteristics of cam profile. then, according to the fact that the lubrication in cam—tappet contact surface is EHD lubrication, taking the interaction between stiffness and damping of unsteady EHD oil film and rigidity of solid object contact into account, a dynamics equation of valve train relating to the dynamic effect of EHD oil film is built up and solved. Consequently, a further study is made on the dynamic characteristics of valve train under interaction of EHD oil film dynamic behavior and the problem of EHD lubrication in cam—tappet pair. Finally, the dynamic effect of full and partial EHD oil film is studied accordingly.

首先，通过对凸轮—挺杆接触为&干接触&的假设，建立了考虑赫兹&接触刚度&和冲击&阻尼&的配气机构动力学模型，用由此求得的凸轮—挺杆表面动载荷对凸轮—挺杆进行了全膜状态和部分膜状态非稳态弹流润滑分析，并研究了凸轮轮廓的磨损规律；然后，是在凸轮挺杆表面存在弹流动压油膜这一事实的基础上，相当于在动力学方程中考虑非稳态弹流油膜的&刚度&、&阻尼&和固体接触&刚度&的耦合作用，建立并求解了考虑弹流润滑行为动力学效应的配气机构的动力学方程，从而深入地研究了弹流润滑行为与动力学行为耦合作用下的配气机构动力学特征以及凸轮挺杆弹流润滑问题；作为前面工作的对应部分，考虑弹流油膜动力学效应的研究工作也同样分为全膜状态和部分膜状态进行。

With CAE analysis, multi-body dynamic model of the loader is established with multi-body dynamics software of finite element NAS-TRAN and MSC Adams/View during design period. Various curve functions are added in dynamic analysis model to simulate the terrain excitation on tires and conduct dynamic calculation and analysis. Stress change vs. time of each part is easily obtained when a loader travels on rough terrain. Compared with test results of the physical prototype, the calculation results are relatively consistent.

利用CAE分析手段，在产品的设计阶段，利用有限元NASTRAN和MSC Adams/View多体动力学软件建立装载机的多体动力学模型，通过在动力学分析模型上加入各种曲线函数来模拟路面对轮胎的激励，进行动力计算分析，很容易获得装载机在通过不平路面时各部件应力随时间的变化值，并将其计算结果与物理样机的测试结果进行对比，两者的结果比较一致。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失