地震损耗能量的分形与混沌规律在实际结构中的应用

根据 Ed和 Ie动力系统的分形与混沌内在属性——短期演化行为的可预测性和长期演化行为的概率特征 ,分别探讨其长短期行为演化规律 .根据短期行为的预测结果 ,探讨了实际工程结构中的主被动抗震参数控制、在役维护的确定以及系统输入能量优化等问题 ;根据长期行为的概率预测结果 ,对实际工程结构中的抗震设计概率、在役维护概率、地震危险性与地震危害性进行了分析 ,为抗震理论和分析方法以及控震减震规律的实际应用提供了一定的参考价值     

带缝钢筋混凝土高剪力墙地震动下的非线性性能(英文)

针对作者新近研制的一种抗震处自控结构带缝钢筋混凝土高剪力墙,本文计算分析了该结构的非线性地震反应．基于一个简化的计算模型,文中的分析集中于缝槽间连梁的非线性性能对整体结构地震动下表现的影响．计算表明,缝槽间连梁的屈服能大大减小结构的地震反应,而且选择合适的连梁屈服强度,可使带缝剪力墙结构的地震反应得到最佳控制．     

Damage behavior of steel beam-to-column connections under inelastic cyclic loading

Brittle cracks were observed in the welded beam-to-column connections of steel frames during an earthquake. The crack propagation and accumulated damage to the connections can lead to fractures at much lower ductility ratios. Understanding the connections’ damage behavior during an earthquake is crucial for the design of steel moment frames in seismic areas. Nine full scale beam-to-column connections were tested under constant amplitude and variable amplitude cyclic loading. The effects of loading amplitude, loading history, and peak load on the connection damage were analyzed. The damage characters were studied and three damage evolution models were calibrated and validated based on test results. The damage mechanism was investigated and an effective plastic strain index was developed to evaluate connection damage based on a ductile fracture mechanism. A fatigue fracture mechanics-based model, for evaluating the damage process of beam-to-column connections under cyclic loading, was proposed.     

16MnR临界空穴扩张比的测试与分析

应用细观力学的观点分析压力容器材料韧性断裂的力学条件,并考察其与断裂参量的关系。在此基础上,对压力容器常用材料16MnR钢的断裂参量进行了测试,结果表明,16MnR钢的宏、细观临界空穴扩张比(VGC)均是不敏感于应力的材料常数,且16MnR钢韧性断裂的早期行为符合R-T模型。此外,还对VGC的测试方法提出了改进。     

关于农民自建低层住宅现状的分析

随着农村经济的发展,农民自建低层住宅建设活动繁荣。但是农民自建低层住宅建筑市场秩序很不规范,尤其是农村建筑施工队问题很多。为保障农民自建低层住宅的建设质量,降低其建设活动中的不安全施工隐患,提出一些关于管理建筑施工队包工头和技术工匠,还有乡镇直接监管农民自建低层住宅建设活动的监管机构的建议。     

Static and dynamic damage analysis of mass concrete in hydropower house of Three Gorges Project

This paper establishes a 3D numerical model for 15# hydropower house of the Three Gorges Project (TGP) and performs a nonlinear static and dynamic damage analysis. In this numerical model, a coupling model of finite and infinite elements for simulating infinite foundation of hydropower station is adopted. A plastic-damage model based on continuum damage mechanics, which includes the softening and damage behavior under tension is considered for the concrete material. The dynamic equilibrium equations of motion are solved by using the HilberHughes-Taylor (HHT) time integration method. Firstly, the static damage response analysis of the hydropower station is conducted due to high tensile stress resulting from large water head and diameter of an inlet pipe. Then, on the basis of static simulation, the dynamic damage analysis of hydropower house subjected to earthquake motion is simulated. Numerical results show that under large water head and diameter of an inlet pipe of the project, the damages are mainly located near the top of the spiral case from the inlet section to the 0° section; under combined loadings of static loads and earthquake, the damages of the concrete surrounding the spiral case increase insignificantly; however, some damages occur on the side walls of the main powerhouse.     

Experimental study on improving seismic behavior of load-bearing masonry wall made of autoclaved aerated concrete

To investigate the seismic behavior of autoclaved aerated concrete load-bearing masonry wall（AACLMW）, a piece of control block wall without constructional measures and five pieces of block walls with different constructional measures were tested under low reversed cyclic loading which imitated low to moderate earthquake force. The seismic behavior of AACLMW with different constructional measures in terms of failure mode, hysteretic curve, deformation capacity and displacement ductility was studied and compared with that without constructional measures. The experimental results indicate that the constructional measures comprising constructional columns and horizontal concrete strips are effective for improving the seismic behavior of AACLMW. The study in this paper can provide a reliable experimental basis for further analysis and engineering application of AACLMW in the future.     

提高村镇建筑抗震设防能力的基本对策

本文通过分析目前村镇建筑在抗震设防方面存在的诸多问题,从规划、设计、管理等几方面提出了基本满足现阶段抗震防灾需要,又切实可行的对策和措施,对村镇建设有一定的借鉴意义。     

利用高延性水泥基材料抑制钢/混凝土连接区域的断裂破坏(英文)

为了避免混凝土的脆性断裂破坏,在钢/混凝土连接区域中用高延性水泥基材料(ECC)代替了普通混凝土. 采用剪力键/ECC 的抗剪试验、二维锚固螺栓/ECC 拔出试验和有限元模拟研究了 ECC 材料的延性对于连接区域破坏模式、结构性能的影响. 实验结果表明: 通过微观力学原理设计的 ECC 具有 300 倍于普通混凝土的拉伸延性,从而使钢/混凝土连接区中混凝土断裂破坏模式由脆性转变为延性. 混凝土材料的高延性使结构承载能力和变形性能获得改善,这也同时为有限元模拟结果所验证. 通过改变混凝土材料延性而提高结构性能的理念也可在其他类似的钢/混凝土组合结构中得到应用.     

复合材料叠层圆柱壳的非线性动力稳定性分析

本文用汉密尔顿原理导出了复合材料叠层圆柱壳的非线性动力稳定性的控制微分方程。在基本方程中包括了非线性大挠度、圆柱壳的初始几何缺陷,以及动力载荷的惯性力等因素的影响。本文的目的是分析复合材料圆柱壳的参数共振和确定壳体结构动力屈曲时的稳定性区域和不稳定性区域,作为求解的例题,本文对三种复合材料圆柱壳进行了数例计算:即 T300—5208石墨-环氧壳体,ARALL 叠层铝合金壳体,和 E-玻璃-环氧壳体,结果表明它们具有相当不同的动力稳定性能.由本文所得出的计算结果和分析结论对于考虑和设计复合材料圆柱壳的动力稳定性具有重要的实用意义.     

混沌反演算法在地震预报中的应用

混沌动力学引人到地震预报之中，介绍混沌反演算法．在王乐群［１］等长期观测获得的地声数据基础上，利用混沌反演计算理论，建立地震混沌动力系统的数学模型并对地声进行预测；结合Ｎ型发震规律和著名的Ｇ－Ｒ关系，提出基于地声对地震行为进行中短期的预测预报；计算实例预测出的地声数据反映出动力系统出现混沌行为．     

A DEVELOPMENTAL APPROACH TO MATHEMATICS TESTING FOR UNIVERSITY ADMISSIONS AND COURSE PLACEMENT

Decisions on admissions to university and placement into university courses are usually based on the results of achievement (as in secondary school exams) and/or aptitude (in intelligence-type tests and SAT). This paper argues that in a situation where educational provision at secondary school level is highly unequal, a third approach to testing offers an alternative which is preferable both on grounds of theory of cognitive psychology and because it yields much better discrimination.The Alternative Admissions Research Project at University of Cape Town has developed a mathematics test according to the dynamic testing approach as advocated by Miller (1990) for admission of African students from grossly under-resourced schools, as well as for placing these and other students into a diversifying first year curriculum. This approach aims to assess the ability of a candidate to learn from authentic academic material within the test. This paper focuses on the reasons for the development of the mathematics test and the process by which the test questions were developed and piloted. The reliability of the test and correlations of this test with subsequent mathematical performance data are discussed.Following the encouraging data for the test as an admission mechanism, the value of the dynamic testing approach for furnishing additional information for placement into an increasingly varied curriculum at first year level was investigated. This enabled the piloting of more topics and more comprehensive validation of this type of testing. The paper concerns itself with the reliability and predictive value of each of the topics in this placement test for a range of core courses in various faculties and the extent to which these tests can identify potentially at risk students who should be placed onto an appropriate curriculum.     

拟内射模及其应用

模论在现代代数学中起着越来越突出的作用。内射模是模论中的一个有着基本重要性的概念。拟内射模是比内射模更广的一类模。本文讨论了拟内射模的性质和刻划。并应用它给出了几种环的拟内射性刻划。在一般教科书中这些环都是用内射性来给出其外刻划的。     

Dynamic properties of composite cemented clay

INTRODUCTIONSoftsoilsarewidelydistributedinChinasco-astalareas.The1985earthquakethatinflictedgreatdamagetoMexicoCitysitedonsoftsoilfounda-tionsgreatlyattractedattentionofresearchersandengineersandmovedthemtostudythedynamicpropertiesofsoftsoils.Manyresearcheshavebeendedicatedtothestudyofdynamicpropertiesofsoftsoils.InChina,deepcementmixingmethodshavebeenwidelyusedinthecoastalareas.Theme-chanicalpropertiesofthesecompositefoundationsoilsarenotthesameasthatofundisturbedsoftsoilsorotherkinds…     

Dynamic properties of composite cemented clay

In this work,the dynamic properties of composite cemented clay under a wide range of strains were studied considering the effect of different mixing ratio and the change of confining pressures through dynamic triaxial test. A simple and practical method to estimate the dynamic elastic modulus and damping ratio is proposed in this paper and a related empirical normalized formula is also presented. The results provide useful guidelines for preliminary estimation of cement requirements to improve the dynamic properties of clays.     

Seismic Behavior of Frame with Specially Shaped Columns Subjected to Cyclic Load

In order to study the seismic behavior of frame with specially shaped columns,the hysteretic curve was analyzed based on a quasi-static test of a two-span,three-story frame with specially shaped columns.The top layer framework curve and the corresponding resilience model were obtained from the hysteretic curve.And the stiffness and strength degeneration were also investigated.The results indicated that the stiffness degeneration is not obvious,thus the frame with specially shaped columns has high earthquake-resistant behavior.The resilience model calculated from the test can provide reference for design and nonlinear finite element analysis.     

Shaking Table Test on Out-of-Plane Stability of Infill Masonry Wall

The behaviors of infill wall in earthquakes show that infill masonry walls,which are used as nonstructural elements of concrete frames,are vulnerable when they are subjected to earthquake.In order to achieve an optimal antiseismic behavior,or even stability,two methods of connection are investigated.The shaking table tests,with 1:3 scale walls of two-storey model subjected to horizontal earthquake loads,were carried out to investigate the out-of-plane behaviors with different connections between walls and beams.The test results show that the connection methods employed between walls and beams have a significant effect on the out-of-plane stability of infill walls.The walls bound by bars with the beams perform better than those with inclined bricks without gaps.     

网络视频公开课程学习行为眼动实验研究

为了研究网络环境中不同媒体对学习者学习行为的影响,该研究使用眼动实验采集网络学习者的学习行为数据,测验其学习结果,分析所得实验数据,利用信息加工理论和认知负荷理论分析不同媒体构成的网络课程学习者的学习行为特点,比较不同媒体对学习者学习行为和学习结果的影响,为网络课程的设计开发和网络教学设计提供参考,为远程学习者的在线学习提供建议。     

试论延性钢筋混凝土框架结构的设计要点及其意义

钢筋混凝土抗震结构不仅要满足强度要求,还必须满足延性要求。建筑结构的延性是保证建筑物在受到地震力、风力等荷载的作用下具有一定的耗能能力、产生可控塑性变形破坏、避免突然脆性破坏的主要条件。文章介绍了框架结构概念设计和延性设计的意义,通过分析多次震害框架结构破坏特点,提出了延性设计的一些思路和方法。     

具有阻尼结点的半刚性连接框架的地震响应(英文)

通过基于随机振动理论的虚拟激励法,分析了具有非比例阻尼特性、安装有结点阻尼器的半刚性结点框架.用建立在半刚性节点单元的动力分析有限元程序分析半刚性结点框架的地震响应.结果表明,结点阻尼器能有效地减小半刚性结点框架的地震响应.