A New Flexible Multibody Dynamics Analysis Methodology of Deployable Structures with Scissor-Like Elements

There are vast constraint equations in conventional dynamics analysis of deployable structures,which lead to differential-algebraic equations(DAEs)solved hard.To reduce the difficulty of solving and the amount of equations,a new flexible multibody dynamics analysis methodology of deployable structures with scissor-like elements(SLEs)is presented.Firstly,a precise model of a flexible bar of SLE is established by the higher order shear deformable beam element based on the absolute nodal coordinate formulation(ANCF),and the master/slave freedom method is used to obtain the dynamics equations of SLEs without constraint equations.Secondly,according to features of deployable structures,the specification matrix method(SMM)is proposed to eliminate the constraint equations among SLEs in the frame of ANCF.With this method,the inner and the boundary nodal coordinates of element characteristic matrices can be separated simply and efficiently,especially on condition that there are vast nodal coordinates.So the element characteristic matrices can be added end to end circularly.Thus,the dynamic model of deployable structure reduces dimension and can be assembled without any constraint equation.Next,a new iteration procedure for the generalized-a algorithm is presented to solve the ordinary differential equations(ODEs)of deployable structure.Finally,the proposed methodology is used to analyze the flexible multi-body dynamics of a planar linear array deployable structure based on three scissor-like elements.The simulation results show that flexibility has a significant influence on the deployment motion of the deployable structure.The proposed methodology indeed reduce the difficulty of solving and the amount of equations by eliminating redundant degrees of freedom and the constraint equations in scissor-like elements and among scissor-like elements.

SLE血清微量元素的变化

对34例活动期和稳定期SLE患者血清Zn、Cu、Fe、Mg、Mn、Cd和Pb离子浓度做了测试。和正常对照组比较,活动期和稳定期的血清Zn、Cu、Fe值下降,血清Mg和Mn值升高。血清Cd和Pb值无变化。

125例SLE与正常人头发35种元素ICP检验结果比较

笔者从1996年先后采集SLE患者头发样品1000多例，选出男53例、女72例共125例，其中年龄最大68岁最小仅4岁，其平均39．1岁；同时选择相同性别、年龄正常人125例配对，用ICP法测35种元素，本文报告31种元素检验结果。经t-检验：（平均值的成对二样分析）发现，SLE与正常人比较发中Cd、Ge、Mn、No、Pb、Sb、Ti、V、Ce、Ga、La、Th、Fe、Al等14种元素含量呈正相关；而Cu、Li、Zn、Ca等4种元素含量呈负相关。揭示了SLE患者体内元素代谢不平衡的秘密，为元素平衡医学食疗提供治疗SLE的科学依据。

Mobility Analysis of the Deployable Structure of SLE Based on Screw Theory

Scissor-like element has a number of applications in deployable structures such as planar deployable structure (PDS) and ring deployable structure(RDS). However, the mobility analysis of the multi-loop deployable structures is made more difficulty by the traditional mobility formula, because the deployable structure is a very complex structure with multi-loop. Therefore, On the basis of screw theory, the calculation method of mobility of deployable structures of SLE is thoroughly discussed. In order to investigate the mobility, decomposing and composing structures(DCS) are developed, and the basic units are able to be obtained. On the basis of the deployable structures’ geometrical characteristics, there exists a closed-loop quadrilateral structure and some non-closed-loop quadrilateral structures in PDS. Also, a six legs parallel structure is present in RDS. The basic units’ mobility can be solved by both the methods of screw theory and topology constraint graphs. Then, composing the related basic units, the formula of planar deployable structures’ mobility can be built and solves the mobility of ring deployable structure. The analysis method solves the mobility analysis of the multi-loop deployable structures which is difficulty by the traditional method, and plays an important role in further research about the mobility of other complex deployable structures.

中西医及元素平衡医学诊治SLE远期疗效评价附52例追踪观察

笔者系统论述了52例SLE患者，汲取中西医元素平衡医学联合治疗，能迅速控制病情，消除症状，其结果应及早抓住最佳治疗时机，并逐渐撤掉激素的依赖性，达到常期缓解稳定，提高生存率，延长了生命。

基于剪式线性阵列可展结构对称性的动力学分析方法研究

为了研究剪式线性对称阵列可展结构的动力学特性,基于杆系能量泛函,建立剪式单元的等效质量矩阵,继而组装得到剪式可展结构的等效质量矩阵。考虑剪式铰的基本约束关系,利用机械系统动力学方程的增广法建立了适用于任意单元个数的剪式线性阵列可展结构的动力学模型。采用一种高精确度的直接违约校正法对系统的坐标和速度进行修正,避免了数值结果的发散。最后通过多步长Runge-Kutta法完成数值仿真,获得了该机构运动过程中各节点位置、速度及加速度随时间变化的曲线。结果表明:由于剪式可展结构的几何约束以及外载的影响,导致各节点沿阵列方向其对称特性表现较好;同时,在受力一侧,各节点沿x轴动力学特性变化较明显,而非受力一侧,速度、加速度等物理量变化幅度很小。

运动副间隙耦合作用下平面剪式线性阵列可展结构的动力学分析

为了研究剪式线性阵列可展结构在运动副间隙耦合作用下的动力学特性,通过含间隙转动副元素之间的运动规律建立了可展结构的运动学模型。基于Gonthier接触力模型以及Lu Gre摩擦模型分别计算了含间隙转动副元素之间的法向与切向接触力。进一步把该接触力转换到间隙运动副所连接杆件的质心处,并将其集成到剪式可展结构动力学模型的广义力中,从而将关节间隙效应引入到剪式机构中。仿真结果表明:考虑2个间隙铰链耦合时,加速度和碰撞力出现了高频振荡的特性;随着间隙尺寸的增加,加速度响应和约束反力的幅值增加,并且碰撞时间被延长;不同位置的铰链相对于间隙尺寸具有不同的敏感度,一个间隙铰链中的运动将影响其他间隙铰链中的运动,表明在可展结构中不同间隙铰链间会产生动力学相互耦合作用。为了更准确地描述可展结构的动力学行为,所有的铰链都应该被模拟为间隙铰链。

剪式机构阵列可展结构的静力学分析方法与应用研究

针对大型可展结构提出了一种新的结构静力学分析方法,克服了常规有限元方法在进行大型可展结构分析时计算量大、计算耗时长等缺点。首先建立了剪式单元机构的刚度矩阵,组装得到整体结构的刚度矩阵和有限元方程;然后通过等价变形,将总刚度矩阵表示成循环矩阵,有限元方程表示成离散卷积的形式;最后采用一种新的方法求解了卷积形式的平衡方程,得到了各铰链点的位移和约束力,提高了计算效率。

剪式机构线性阵列可展结构的动力学特性研究

基于笛卡儿坐标系建立了剪式机构线性阵列组成的可展结构动力学模型,利用运动副等约束条件建立了剪式可展结构的运动约束方程。采用Runge-Kutta法进行数值计算,获得了该种机构式结构运动过程中的速度和加速度等规律,绘制了阵列组合机构的运动曲线,为该种结构的应用奠定了基础。结果表明,剪式机构线性阵列在展开过程中具有不一致的水平速度。

元素平衡医学食疗与发热急救

笔者用元素医学食疗法对非感染性高热、系统性红斑狼疮持续高热二十余人急救成功。对癌症、白血病、类风湿等患者高热或持续低、高热治疗有效。对感染性的流感高热和艾滋病高热或持续低热治疗有效。笔者认为，人体内元素代谢平衡是人体温度平衡非常重要调节因素之一。人体高热或持续高热是由于人体内元素代谢不平衡引起人体防御疾病和适应内外环境异常的代偿性反应亢进、代偿性反应持续亢进。元素医学食疗应是流感、“非典”首选疗法。