考虑土-结构相互作用下不规则建筑振动控制分析

当建筑物建造于比较软的地基之上,土-结构相互作用会导致土-结构相互作用体系的动力特性发生改变,以至于影响建筑振动的控制效果.因此,在分析建筑振动的控制时要考虑土-结构相互作用.本文主要是从土-结构相互作用下不规则建筑振动的被动控制、主动控制和半主动控制三个方面进行分析,综合论述了土-结构相互作用下不规则建筑振动的控制问题.     

新型海洋平台土与结构相互作用的动力层元法分析

用动力层元法（ＤＦＬＥＭ）分析了新型海洋平台的土与结构的相互作用．结果表明动力层元法是分析土与结构相互作用的有效方法，工程应用前景广阔．     

土与结构动力相互作用隔震体系的MB计算方法

采用刚性地基假定是目前结构控制研究的基本条件,此假定忽略了土与结构相互作用效应的影响。但由于土与结构相互作用效应对结构振动特性有一定的影响,进而影响结构控制的效果,因此有必要研究土与结构动力相互作用的简化计算方法。基于上述原因,进行了线性体系土与结构相互作用效应对隔震体系的MB计算方法的研究。     

微型桩材料对桩—土动力相互作用的影响分析

利用ABAQUS有限元软件,开展不同材料微型桩—土动力相互作用的影响研究,桩身材料分别选为C40普通混凝土、C60普通混凝土、钢管混凝土、RPC混凝土。分析结果表明,由于弹性模量发生变化,不同材料微型桩的桩身弯矩存在明显差异;桩身材料的弹性模量过大会使微型桩的变形减弱;与静力荷载作用不同的是,动力荷载作用下的微型桩在上、下土层范围分别出现了一正一负两个较明显的桩周土反力峰值点。相关研究结论对指导微型桩的设计具有参考价值。     

干湿循环下重塑膨胀土动力特性分析

基于干湿循环下重塑膨胀土的动三轴试验结果,从动应力、动弹性模量、阻尼比和弹塑性变形的变化关系分析膨胀土的动力特性。结果表明:在不同的干湿循环次数下,动弹性模量均随动应变的增大而减小;用指数衰减模型确定了不同干湿循环次数下的最大动弹性模量,且第1次干湿循环对最大动弹性模量影响显著;阻尼比随着干湿循环的增加而增大,随着动应变的增大而逐渐趋于平缓;弹性变形随动应力幅值呈线性增大,且干湿循环对弹性变形有增强效果。弹性变形随振动次数的增加出现2种变化:振动稳定时,弹性变形随振动次数的增多趋于稳定;振动破坏时,弹性变形在振动前期快速破坏。     

桩土相互作用及单桩承载力确定模拟研究

以灌注桩桩土相互作用的原位试验为基础,结合苏嘉杭高速公路具体土层结构、性质特点,采用有限单元法对软土地区的砼灌注桩桩土相互作用进行仿真模拟,研究桩土相互作用、荷载的传递规律、桩土相对位移与桩侧摩阻力的关系,通过桩载试验资料对比,得出三维有限元法的模拟结果与实测值相近.在此基础上,根据侧摩阻力最大值发挥不同步这一特点和桩土相互作用的实质及荷载传递规律,提出一种新的单桩极限承载力计算公式.     

桩土相互作用及单桩承载力确定模拟研究

以灌注桩桩土相互作用的原位试验为基础,结合苏嘉杭高速公路具体土层结构、性质特点,采用有限单元法对软土地区的砼灌注桩桩土相互作用进行仿真模拟,研究桩土相互作用、荷载的传递规律、桩土相对位移与桩侧摩阻力的关系,通过桩载试验资料对比,得出三维有限元法的模拟结果与实测值相近。在此基础上,根据侧摩阻力最大值发挥不同步这一特点和桩土相互作用的实质及荷载传递规律,提出一种新的单桩极限承载力计算公式。     

预应力锚杆复合土钉支护三维非线性分析

应用三维非线性有限元分析通用软件,对基坑工程中采用预应力锚杆复合土钉支护和单纯土钉支护2种支护方式进行数值模拟分析,包括分步土方开挖、土钉安设与面层制作等全过程的施工模拟,对同等工况下的单纯土钉支护和预应力锚杆复合土钉支护进行力学性状比较,包括坑外土层张拉应力区分布、变形特征、支护坑壁力学特征和土钉与锚杆拉力分布等方面的差异性,并结合复合土钉支护基坑工程应用情况,系统地研究了预应力锚杆复合土钉支护作用机理及其工作性能.     

动力定位浮托安装船待命就位工况时域模拟

开发了动力定位浮托安装法时域模拟工具,对某浮托安装船在动力定位方法下的待命就位过程进行了时域模拟研究。通过构建时域模拟模型,对该浮托安装船在各种海洋环境下的待命就位工况进行分析,得到该浮托安装船的位置偏移与消耗功率的时历与统计值。时域数值模拟的结果表明,该动力定位浮托安装船能够在180°和0°环境载荷作用下实现较为理想的待命就位,且在180°环境载荷作用下待命就位时,能避免驳船的推进器倒车,取得更好的定位精度和较小的功率消耗,是最佳的待命就位方向。该时域模拟的结果与分析,为实际的海上实船安装提供必要的理论与实践指导。     

8000 m~3耙吸式挖泥船动力定位系统时域模拟与模型试验

针对耙吸式挖泥船动力定位系统,以某8 000 m~3耙吸式挖泥船为研究对象,分析其动力定位系统在模拟海况下的定位能力与特点,构建出动力定位时域模型。对挖泥船在各种海况下的实时运动进行时域模拟分析,得到该挖泥船的偏移半径时历和功率消耗时历,并进行相关模型试验。时域模拟与模型试验结果表明,该挖泥船动力定位系统仅可在较小艏向角范围内完成有效定位,由于舵转角的限制,螺旋桨无法在较大艏向角的情况下提供足够的转船力矩完成定位。通过模型试验与时域模拟结果的分析与比较,为动力定位时域模拟程序进一步优化提供参考。     

Influence of structure plane size on seismic response of soil-structure interaction

The influence of the change of structure plane size on seismic response was studied for a soil-structure interaction system. Based on the finite element method, a soil-structure interaction calculation model was established to analyze the seismic response by changing the structure plane size and choosing different earthquake waves for different soil fields. The results show that when the natural periods of vibration for different structure plane sizes are close, under the same earthquake wave, the total displacement on the top layer of the structure and the foundation rotation displacement decrease with the increase of structure plane size, and the proportion of superstructure elastic selfdeformation displacement to the total displacement increases with the increase of structure plane size. While for different types of sites and seismic waves, under the horizontal and vertical seismic waves, the seismic responses of different plane sizes have a similar change rule.     

结构动力响应分析的一种简便的直接积分法

提出了一种简单且有效的可应用于线性和非线性系统响应分析的直接数值积分方法，并就算法稳定性作了扼要的分析。与一些常用的直接积分方法(如差分法、Wilsonβ及Newmarkβ法等)不同的是：文章提出的方法首先由控制方程计算加速度，然后基于位移、速度和加速度的近似关系式导出位移及速度的计算公式。文中给出了若干个数值算例，其结果表明该方法对于线性和非线性系统的动力响应分析是较为有效的。     

Direct and relaxation methods for soil-structure interaction due to tunneling

This paper deals with the problem of tunneling effects on existing buildings. The direct solution, using the condensation method, is presented. This method allows the structural and geotechnical engineers to treat the problem separately and then assemble a relatively small matrix that can be solved directly, even within a spreadsheet. There are certain concerns that the resultant matrix may be ill-conditioned when the structure is very stiff. This paper suggests an alternative method that essentially relaxes the system from an infinitely rigid structure solution. As such, it does not encounter the problems associated with stiff systems. The two methods are evaluated for an example problem of tunneling below a framed structure. It is found that while the direct method may fail to predict reasonable values when the structure is extremely rigid, the alternative method is stable. The relaxation method can therefore be used in cases where there are concerns about the reliability of a direct solution.     

An overview of structure-soil-structure dynamic interaction research

The concept of structure-soil-structure dynamic interaction was introduced and the research methods were summarized. Based on lots of documents, a systematic summary of the history and current situation of structure-soil-structure dynamic interaction research considering adjacent structures was proposed as reference for researchers. The existing matter and the prospect of future research trend in this field was also examined.     

Exploring classroom interaction with dynamic social network analysis

This article reports on an exploratory project in which technology and dynamic social network analysis (SNA) are used for modelling classroom interaction. SNA focuses on the links between social actors, draws on graphic imagery to reveal and display the patterning of those links, and develops mathematical and computational models to describe and explain those patterns. Dynamic SNA extends SNA and builds on previous research on network change. Utilizing data from six videos from the TIMSS video study and a convenience sample of five observations of one teacher in a secondary school in the south of England, a methodology for dynamic SNA was applied to classroom interaction data. The results are in two ways relevant for this journal. Firstly, they show that recent developments in SNA might be usefully applied to furthering knowledge about the dynamics of classroom interaction. Secondly, the results provide an example of the use of tablet technology for fieldwork data collection.     

二阶系统的时域分析软件实验平台设计

介绍了"自动控制原理"实验教学中的一个二阶系统的时域分析软件实验平台的设计.该实验平台具有实验参数易于调节和实验结果更直观等特点.利用此平台进行实验教学,提高了该课程的实验教学效果和质量,增强了学生对基本概念的理解能力,培养了学生独立研究与创新能力,激发了学生对该课程的兴趣和理解.     

用于时域计算场的分形脉冲构造及其谱分析

为了实现随机场的时域计算,在广义时间序列的基础上,构造了两种自相似时间脉冲信号,给出了它们的谱结构因子和谱形状因子的递推公式,从而得到相应的谱图。对这些脉冲信号的谱域特征进行分析,为在频域中认识自相似信息提供了依据。     

"有效教学"辨

Reflecting on nearly half a century’s research on “effective teaching”, this essay attempts to arouse a lot of suspicion, including ambiguous definition of connotation, a false antithesis and the imbalance between teachers and students. Accordingly, this study further reveals hidden thinking obstacles, such as over-reliance on technical rationality, wrong inference and the separation of the dialectical relationship between teaching and learning. As a future research direction, the ideal teaching should focus on virtue rather than efficiency, giving consideration to effectiveness and responsibility. __________ Translated from Quanqiu Jiaoyu Zhanwang 全球教育展望 (Global Education), 2007, 36(7): 17–22     

初探非线性编辑系统的网络实现

与传统的编辑制作系统相比,非线性编辑系统在素材编辑、特技制作、制作效率等方面的优越性和灵活性有了很大提高,但在信息处理容量、传送方式、节目和资源的共享等方面还不够完美.随着网络技术的日臻完善,基于网络技术和非线编技术的非线性编辑网络已经大量应用于电视节目制作中,真正实现了非线性工作组共享模式的非线性编辑网络.