南京小龙湾大桥动力特性分析

以南京小龙湾大桥为研究对象,基于自锚式悬索桥合理成桥状态空间有限元模型,研究结构参数变化对其动力特性的影响,并与相同结构参数的地锚式悬索桥模型进行对比.结果表明:自锚式悬索桥由于塔顶位移约束程度较弱以及主梁承受主缆传来的水平分力,减小了结构体系的刚度,因而比相同结构参数的地锚式悬索桥的振动频率小;恒载、加劲梁竖向刚度和主缆刚度的变化对结构的低阶频率影响较大.研究结果可为类似结构动力特性分析提供参考.     

结构参数变化对自锚式悬索桥动力特性的影响

自锚式悬索桥的动力特性主要包括体系的自振频率和主振型,它是自锚式悬索桥动力分析的基础和前提.通过建立空间有限元模型及工程实例,给出了前20阶频率和相应的振型,分别计算了恒载、加劲梁刚度、塔架刚度、矢跨比等结构参数变化对自锚式混凝土悬索桥动力特性的影响,并与相同跨径和结构参数的1座地锚式悬索桥进行了比较,对影响规律做了详细的讨论.     

三塔自锚式悬索桥模型试验研究

介绍福州市螺洲大桥试验模型的设计、试验过程和试验研究结果.通过对实测结果与有限元计算结果的分析对比,研究三塔自锚式悬索桥这一新型结构形式的静力行为.结果表明,三塔自锚式悬索桥的结构变形和内力与外荷载基本呈线性关系,主梁挠度与主塔的水平位移之间存在密切关系,主塔刚度对多塔自锚式悬索桥的竖向刚度影响较大.     

混凝土自锚式悬索桥模型试验研究

抚顺市万新大桥全长476.15m,主桥为15m 70m 160m 70m 15m的双塔双索面混凝土自锚式悬索桥.模型试验对万新大桥主桥模型的静力性能和动力特性进行了详细研究,并与理论计算结果进行了比较,模型试验结果与理论分析相吻合.试验表明中小跨度混凝土自锚式悬索桥的受力基本符合线弹性,可以用线弹性理论进行分析;用现有的有限位移理论分析混凝土自锚式悬索桥的静力和动力特性,并进行抗风、抗震设计是可靠的.     

大跨度CFRP缆索悬索桥的静力性能

基于分段悬链线法和通用有限元程序,提出了一套悬索桥静力性能分析的方法和步骤,并利用该方法对主跨为2 000~5 000 m的悬索桥静力性能进行了对比研究,验证了CFRP缆索悬索桥的静力优势和可行性。针对此类桥型刚度较小的缺点,对跨径为2 000 m的CFRP缆索悬索桥的刚度性能进行了参数分析,考虑的设计参数包括：桥跨布置方式、矢跨比、边中跨比、主梁抗弯惯矩、桥塔抗弯惯矩和中央扣。最后提出了改善结构刚度设计的建议。     

混凝土自锚式悬索桥设计及其力学性能分析

大连市金石滩悬索桥全长198m，主桥是24m 60m 24m的自锚式混凝土悬索桥，为中国首座此类桥梁。计算实例证明弹性理论适合于中小跨度的自锚式悬索桥的设计和计算。不计主梁轴力，结构的其余内力与地锚式悬索桥的差值在10％以内。拱度和混凝土的收缩、徐变的影响比较明显。与相应的水平加劲梁和不考虑收缩、徐变影响的计算结果比较，差值均在20％以上。分析所得结论对于同类桥梁的设计和研究具有一定的参考价值。     

自锚式悬索桥静力行为影响因素分析

分析了自锚式悬索桥等代梁的特点,对某座具体桥梁进行了有限元参数分析,并用等代梁解释分析结果,确定不同影响因素对于自锚式悬索桥静力行为的影响程度.研究结果表明,为了改善自锚式悬索桥的静力行为,可以增加主跨主缆垂跨比、主梁拱度、主缆材料的弹性模量、主梁材料的弹性模量、主梁截面惯性矩、吊索材料的弹性模量、吊索的截面面积,减小吊索的长度.     

自锚式混凝土悬索桥的动力分析

研究自锚式混凝土悬索桥的动力学性能 .以一新建自锚式混凝土悬索桥为背景 ,首先运用有限元分析获得其动力特性并与地锚式悬索桥进行比较 ,然后利用实桥环境振动试验验证有限元动力特性分析结果 ,最后由地震反应分析进一步考察自锚式悬索桥的振动特点 .结果表明 :自锚式悬索桥由于主缆直接锚固于主梁端 ,主塔纵向弯曲振动频率明显降低 ;因结构耗能方式也随之发生了变化 ,主塔和主梁在纵向地震输入下的各种反应均呈不同程度的增加 .     

空间缆索体系对自锚式悬索桥的动特性影响研究

为了探索理想的自锚式悬索桥缆索体系以提高桥梁在地震作用下的稳定性,以吉林某自锚式悬索桥为工程实例,设计另外两种不同缆索体系的自锚式悬索桥。运用自振特性的研究方法对其自振特性进行分析;运用时程分析方法,对其自地震作用下的稳定性进行分析。结果表明：自锚式悬索桥采用内倾式空间缆索体系时,结构的侧弯及扭转频率增大,对动力特性有利;采用外倾式空间缆索体系时,结构的侧弯及扭转频率减小,对动力特性不利;在纵向地震波作用下,外倾式与平行缆索体系的结构响应更小;在横向地震波作用下,内倾式与平行缆索体系的结构响应更小。     

大跨度自锚式悬索桥稳定性研究

利用大跨度悬索桥的挠度理论,建立了自锚式悬索桥加劲梁在恒载、恒载与活载及活载下的变形与荷载的平衡方程.对所建立的方程进行分析后,得到了如下结论:自锚式悬索桥加劲梁在恒载状态设计时,应按受横向荷载作用的压弯梁验算面内稳定性,但是活载作用下不存在面内稳定问题.此外提出了自锚式悬索桥的静力特性可以比拟为变高度连续桁架梁的观点,用此观点解释了所得到的理论研究结论.通过一座实桥的极限承载力分析和在根据实桥按比例制作的全桥试验模型上进行超载试验,证明了本文理论分析的结论是正确的.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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