天圆地方连接管的某建模编程放样方法的探讨

针对天圆地方连接管道在制造过程中遇到的放样难的问题,可以采用一种建模编程放样方法代替传统手工作图方法来加以解决。首先通过理论推导得到数学模型,然后编制程序软件进行应用。实际工程应用的结果非常好,证明该方法是行之有效的正确方法。此建模编程放样方法的原理能够进一步推广到钣金放样的相关领域。     

单芯片实现高速摄像机运动控制系统的一种设计方案（系统分析篇）

作者描述了作为高速球型摄像机运动控制系统主要执行元件——步进电机的驱动原理和控制方案。报告应用基于模型的技术,分析了步进电机的特性,设计了一种在单芯片（SoC,System On Chip）上实现的新型高速球型摄像机运动控制的电子系统级方案。该方案针对步进电机高精度驱动控制设计需求,建立了运动控制电子系统各个设计层次上的模型,通过仿真探索其系统架构及性能优化。文章分两篇组织,系统分析篇（设计目标,系统分析）和系统综合篇（系统设计）。     

铸钢索夹节点在弦支穹顶结构中的应用

铸钢节点作为一种新型的节点形式正越来越多地应用于空间钢结构中.常见的铸钢节点形式有铸钢球节点、铸钢相贯节点及铸钢支座节点.结合武汉体育馆弦支穹顶钢屋盖工程,介绍了另一种铸钢节点--铸钢索夹节点,并对该类铸钢节点的设计、有限元计算与分析进行了探讨,以期给类似工程设计提供参考.     

Geometrical nonlinear stability analyses of cable-truss domes

The nonlinear finite element method is used to analyze the geometrical nonlinear stability of cabletruss domes with different cable distributions. The results indicate that the critical load increases evidently when cables, especially diagonal cables, are distributed in the structure. The critical loads of the structure at different rise-span ratios are also discussed in this paper. It was shown that the effect of the tensional cable is more evident at small rise-span ratio. The buckling of the structure is characterized by a global collapse at small rise-span ratio; that the torsional buckling of the radial truss occurs at big rise-span ratio; and that at proper rise-span ratio, the global collapse and the lateral buckling of the truss occur nearly simultaneously. Project (No. 50278086) supported by the National Natural Science Foundation of China     

Initial pre-stress finding procedure and structural performance research for Levy cable dome based on linear adjustment theory

The cable-strut structural system is statically and kinematically indeterminate. The initial pre-stress is a key factor for determining the shape and load carrying capacity. A new numerical algorithm is presented herein for the initial pre-stress finding procedure of complete cable-strut assembly. This method is based on the linear adjustment theory and does not take into account the material behavior. By using this method,the initial pre-stress of the multi self-stress modes can be found easily and the cal-culation process is simplified and efficient also. Finally,the initial pre-stress and structural performances of a particular Levy cable dome are analyzed comprehensively. The algorithm has proven to be efficient and correct,and the numerical results are valuable for practical design of Levy cable dome.     

球型摄像机高速运动控制驱动策略的SoC实现方案—系统综合篇

作者描述了作为高速球形摄像机运动控制系统主要执行元件—步进电机微步驱动控制的SoC实现方案。报告应用基于模型的分析描述以及基于步进电机特性的物理分析结果,设计了一种在单芯片（SoC,System On Chip）上实现的新型高速球形摄像机运动控制的电子系统级方案。该方案针对步进电机高精度微步驱动控制设计需求,建立了运动控制电子系统微步驱动策略各个设计层次上的模型,通过仿真探索其系统架构及性能优化。这篇文章也是《单芯片实现高速摄像机运动控制系统的一种设计方案—（系统分析篇）》的续篇—系统综合篇。     

Geometrical nonlinear stability analyses of cable-truss domes

INTRODUCTIONThetensegritystructurecomposedofcablesandbarsisoftwotypes.Oneistheflexibletensegritystructure.Thistypeofstructurehasnostiffnessandtheshapeofthestructureisnotde terminedwhennoprestressisapplied .Theform findingprocessfortheinitialequilibriumisa…