Overview of Existing Lunar Base Structural Concepts

Various structural concepts for lunar bases have been proposed and considered during the past three decades, each balancing the multitude of lunar constraints and anticipated base functions with a different distribution of weighting factors. This paper provides a brief review of the study of lunar base structures as well as an overview of current ideas. Lunar environmental characteristics are highlighted, and questions of structural functionality are categorized. In an appendix to the overview report, building systems proposed for lunar applications are categorized according to applications, application requirements, types of structures, material considerations, structures technology drivers, and requirement definitions. Another appendix presents a short list of the most important references related to these issues, as ranked by the task committee. This document contains a brief overview rather than an exhaustive review of concepts proposed for lunar outposts. The original documents, including those cited as references, are not replaced by this paper. However, this review is intended to be reasonably complete. There has been no conscious intention to ignore any work in this area of extensive ongoing activity.     

大直径钢管烟囱有限元分析与稳定设计研究

采用单根大直径钢管为主体的钢烟囱体系可兼顾结构性能和使用要求,具有突出优点。本文以工程实例为背景,对单根大直径钢管烟囱结构进行了研究。首先介绍结构荷载计算方法与有限元计算理论;然后探讨了壳体稳定分析方法,并给出相关设计公式和设计步骤;最后结合实际工程给出了设计算例,得到了结构内力、位移和稳定计算结果。本文系统地归纳了有限元分析和稳定设计理论,可供大直径钢管烟囱设计及其相关研究参考。     

靠近振源处土对波传播和结构响应的影响

近源地振动的特点是垂直地面运动非常强烈,并且高频成分多。本文研究了土对从振源到土表面传播的波及结构响应的影响。     

Global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback.Based on a detailed analysis of the stability switches of the trivial equilibrium of the system,the stability charts are given in a parameter space consisting of the time delay and the feedback gains.The center manifold reduc-tion and the normal form method are used to study Hopf bifurcations with respect to the time delay.To gain an insight into the persi...     

半电极含金属芯压电纤维的动态微力传感器

半电极含金属芯压电纤维(HMPF)是一种新型压电传感器.建立了HMPF的动态微力传感理论模型.根据第一类压电方程,基于振动理论,用平均电荷方法,推导出悬臂梁结构HMPF自由端受到垂直动态微力作用后,产生电荷的解析表达式;分析了长度和半径比对产生电荷的影响.实验结果表明,HMPF可以测量动态微力的频率和幅值,具有较高的动...     

能量优化法分析四边域膜结构初始形态

根据膜结构曲面的多样性,提出了描述膜曲面的三次准均匀B样条曲面方程.根据膜结构受力特点,结合其形与态建立总能量方程,通过数学规划求得曲面的控制点,从而求得具有最小变形能膜曲面.     

剪力墙结构优化设计探讨

为了进一步发挥高层剪力墙结构的优点,又克服其存在的缺点,根据建筑物的高度不同,提出了几种改进的现浇剪力墙结构形式.结合现有设计规范和工程经验,说明了这些结构形式的可行性.     

Lubrication Property of Magnetorheological Fluid With Nano-Silica Additives Under Magnetic Field

Magnetorheological(MR)fluid is colloidal suspension and stiffens into semi-solid when subjected to a magnetic field.In order to investigate the effect of magnetic field on lubrication property of MR fluid with nano-silica additives,a pin-on-disc tribometer is used to carry out friction and wear experiment of steel under the magnetic field.The MR fluids with different additive concentrations are prepared and their theological properties are examined via a rotational rheometer.Different lubrication performance of the MR fluid with nano-silica additives with and without magnetic field is presented.In addition,through observing the morphology and analyzing the elemental composition of the worn surfaces,the effects of additives on the lubrication property are investigated.     

A simple algorithm for testing the stability of periodic solutions of some nonlinear oscillators with large time delay

Periodic solutions occur commonly in linear or nonlinear dynamical systems. In some cases, the stability of a periodic solution holds if the rightmost characteristic root has negative real part. Based on the Lambert W function, this paper presents a simple algorithm for locating the rightmost characteristic root of periodic solutions of some nonlinear oscillators with large time delay. As application, the proposed algorithm is used to study the primary resonance and 1/3 subharmonic resonance of the Duffing ...