传感器支架和外加测量体影响电场测量值的实验

为了克服银-氯化银的三分量传感器测得的测量值与电场发生器标准值存在的误差,设计了传感器支架和外加测量体影响电场测量值的实验．在电位和电流连续的条件下,运用麦克斯韦方程组,计算了规则球形测量体引起的电场畸变,并进行了实验验证．实验结果表明,测量体引起的电场畸变不可忽略;测量体处于电极内部会增大测量的电场,处于外部时将降低测量的电场;当测量体离测量电极比较近时,影响较大,反之,影响较小．     

Stability analysis of switched systems using variational principles: An introduction

Many natural and artificial systems and processes encompass several modes of operation with a different dynamical behavior in each mode. Switched systems provide a suitable mathematical model for such processes, and their stability analysis is important for both theoretical and practical reasons. We review a specific approach for stability analysis based on using variational principles to characterize the “most unstable” solution of the switched system. We also discuss a link between the variational approach and the stability analysis of switched systems using Lie-algebraic considerations. Both approaches require the use of sophisticated tools from many different fields of applied mathematics. The purpose of this paper is to provide an accessible and self-contained review of these topics, emphasizing the intuitive and geometric underlying ideas.     

动车水箱安装座的强度计算和结构改进

为使动车上的水箱安装座具备足够的强度,以保证连接的可靠性,利用三维实体建模并用Hyper Works对水箱安装座进行有限元计算;依据EN 12663:2010标准对水箱安装座进行强度校核并针对不满足强度要求的部分进行结构改进.结果表明:改进后的模型设计能够满足EN 12663:2010的标准;CAE软件的应用为水箱安装座的结构设计提供参考.     

On the analysis of nonlinear nilpotent switched systems using the Hall–Sussmann system

We consider an open problem on the stability of nonlinear nilpotent switched systems posed by Daniel Liberzon. Partial solutions to this problem were obtained as corollaries of global nice reachability results for nilpotent control systems. The global structure is crucial in establishing stability. We show that a nice reachability analysis may be reduced to the reachability analysis of a specific canonical system, the nilpotent Hall–Sussmann system. Furthermore, local nice reachability properties for this specific system imply global nice reachability for general nilpotent systems. We derive several new results revealing the elegant Lie-algebraic structure of the nilpotent Hall–Sussmann system.     

基于数值风洞的光伏支架阵列风载荷分布

用计算流体力学方法分析光伏支架阵列风场,研究各倾角和风向角情况下支架阵列中风载荷的分布,提出支架阵列的区域划分和风载荷体型系数取值建议。研究成果对光伏支架阵列结构设计和工程建设具有较好的应用价值。该方法有利于节省材料,降低光伏发电的成本。     

悬置支架强度分析和拓扑优化

在项目研发阶段用Abaqus对某轿车的发动机悬置支架进行强度分析,发现悬置支架不满足强度要求,通过拓扑优化的方法对其结构进行改进,在不增加质量的情况下,使悬置支架达到强度设计目标.     

土压平衡盾构机刀盘牛腿的有限元分析

采用有限元法对土压平衡盾构机的关键部件刀盘牛腿进行静力学分析,同时计算其在受力条件下的前6阶模态的固有频率、振型、相对位移的分布图。分析结果显示出受力薄弱区以及抗震薄弱区,为刀盘牛腿的静力学以及动力学优化提供必要的依据。     

汽车支架零件模拟分析与工艺结构优化

以汽车支架零件为载体,以一步成形法模拟分析理论为基础,应用AutoForm冲压工艺有限元分析软件,针对典型汽车薄壁件的工艺结构进行压延筋结构与压料面尺寸模拟成形工艺分析。结果表明,控制了材料流动,解决了零件冲压成形工艺过程中的开裂问题,优化了材料片尺寸与压延筋工艺结构,取得了良好的应用效果。     

磨刀门特大桥50 m预应力混凝土T梁架设工艺

介绍了SDLB-50双导梁型架桥机的特点及其架设施工工艺,对机过孔法的步骤进行了阐述,并对机械及电气设备日常安全检查方面进行了总结论述,供今后类似桥梁施工参考借鉴。     

现浇箱梁模板支架设计及施工质量控制

现浇箱梁施工方法在目前的桥梁施工应用中较为普遍,支架布设设计的好坏直接关系到混凝土浇筑过程的安全及浇筑成型后的箱梁质量和线形能否符合设计要求,因此,支架的布设及验算极为重要.本文就机场高速立交主线桥连续现浇箱梁施工,结合实际施工经验及现场实际情况,对支架的设计与施工予以详细的介绍.