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1.
预制再生混凝土框架模型模拟地震振动台试验   总被引:2,自引:0,他引:2  
选用不同地震波,通过模拟地震振动台对首例1/4缩尺再生粗骨料取代率为100%的预制再生混凝土框架模型进行了3种地震波输入试验.通过白噪声扫描得到了该模型结构的自振频率、结构振型、阻尼比等动力特性,研究了加速度、楼层剪力、位移动力反应,记录了结构在试验中的开裂等现象.试验分析表明,随着地震动峰值强度的增加,模型呈现自振频率下降、阻尼比增大、加速度放大系数逐渐降低、楼层剪力逐渐增大的趋势;在弹塑性阶段后期,后浇节点刚度退化迅速,层间位移明显增大.采用层间位移作为评估标准,对预制再生混凝土框架的抗震能力进行了评价,表明预制再生混凝土框架抗震性能良好,但应采取必要措施加强梁柱节点的耗能能力.  相似文献   

2.
再生混凝土框架结构模型振动台试验   总被引:6,自引:0,他引:6  
介绍了再生粗骨料取代率为100%的再生混凝土框架模型的振动台试验.对框架模型的自振频率、结构等效刚度、结构阻尼比、结构振型、加速度反应、位移反应进行了研究.分析表明,随着地震强度的增加,结构出现一定程度的破坏后,模型抗侧移刚度退化、自振频率随之下降、结构的阻尼比逐渐增大、加速度放大系数呈逐渐降低的趋势;采用层间变形作为评估指标,对再生混凝土框架的抗震能力进行了评估.经过多次地震试验后,尽管再生混凝土框架的破坏较为严重,但在1.170g地震试验后仍然没有倒塌,表明再生混凝土框架结构具有良好的抗震能力.  相似文献   

3.
本文介绍了普通抗震结构、采取砂垫层隔震技术、砂垫层-基础滑移复合隔震技术的三个双层砌体结构1/4缩尺模型的振动台试验研究结果。这篇研究以结构自振频率、周期、阻尼比及阵型等为指标,通过不同输入地震强度下动力特性对比研究,总结隔震结构的工作机理及动力特性强震演变规律,评价两种隔震技术的隔震效果。结果表明:随输入地震强度增大,自振频率先保持不变后减小,阻尼比先减小后增大,砂垫层隔震结构阵型和复合隔震模型阵型的变化趋势与破坏现象相吻合。动力特性变化表明两种隔震结构的耗能能力较好,隔震效果较好。  相似文献   

4.
设计并进行了10层框架的模型振动台试验,分别进行了低频、中频、高频地震波模型试验.根据模型试验结果,应用不同模型试验数据分析方法——自由振动衰减、半功率法和HHT变换法,得出了模型结构前3阶自振频率及对应的振型阻尼比;再分别采用Rayleigh阻尼假定和Caughey阻尼假定,进行了相应模型结构地震反应的数值模拟,比较了不同阻尼模型之间的差异;较为详细地描述了根据试验结果作出较为合理的数值模拟的过程.  相似文献   

5.
为增大调谐液体阻尼器的减振效果,文章提出了内置挡板调谐液体阻尼器,推导了该新型调谐液体阻尼器的基本运动方程,分析了挡板的耗能减振作用以及该新型阻尼器对结构的附加阻尼比.采用Matlab语言编制了内置挡板调谐液体阻尼器的动力分析计算机仿真程序,对某26层典型算例进行了脉动风激励下的结构动力时程仿真分析,并与普通调谐液体阻...  相似文献   

6.
对一个1:4缩尺的3层铜框架.剪力墙模型结构进行振动台试验研究,分析了该结构在强震作用下的动力特性、动力响应及损伤的演化规律.结果表明,随着地震强度增大,结构前两阶自振频率以及层动力放大系数逐渐减小,结构位移反应增大.提出了基于构件层次的损伤模型,该模型考虑了大变形幅值对累积耗能的影响.用该损伤准则对模型薄弱层钢柱的损伤演化规律进行分析,结合IDA分析的结果以及试验结果,对模型的合理性进行了验证.  相似文献   

7.
为研究行人动力学参数对大跨结构人致振动的影响,采用等效人体模型参数识别试验研究了人体模型的自振频率和阻尼比,编程求解了考虑人-结构竖向相互作用的人行桥人致振动方程,讨论了人体质量、人体刚度、人体阻尼及人行荷载等行人动力学参数对人行桥动力特性及人致振动响应的影响规律.结果表明,人行荷载模型中人体质量可取中国男性居民平均质量66.2 kg.等效人体模型的自振频率和阻尼比分别取为5.15 Hz和35.62%.人行荷载作用下,人行桥一阶瞬时频率先减小后增大,一阶瞬时阻尼比先增大后减小.随着人体质量或人体等效阻尼的减小,瞬时阻尼比和频率的变化幅度均有所减小,但随着人体等效刚度的减小,两者的变化幅度均有所增大.人行桥跨中均方根加速度响应随着人体质量或人体等效刚度的增大也相应增大,而人体等效阻尼对人行桥加速度响应的影响较小.采用不同人行荷载模型计算的人行桥均方根加速度最大值是最小值的1.83倍.  相似文献   

8.
针对传统调谐质量阻尼器(TMD)质量过大难以安装,对频率较为敏感的固有缺陷,碰撞调谐质量阻尼器(P-TMD)将碰撞耗能与传统的TMD相结合以增大装置耗能。在前期的数值模拟研究中,P-TMD在地震激励下展现了比TMD更好的控制效果及控制稳定性。根据P-TMD的数值模型设计制作了一个用于水平向减振的集成P-TMD装置原型,并将装置安装于一柔性框架结构进行了地震激励下的减振试验。试验结果验证了P-TMD在不同地震激励下都可以对结构响应进行有效控制,控制效果相对稳定;特别对加速度峰值和均方根值的控制效果可达40%以上,相比TMD控制的效果提升明显。本文结果可以为今后P-TMD的进一步研究和应用提供必要的试验支持。  相似文献   

9.
巨型框架减振结构的动力时程分析   总被引:3,自引:2,他引:1  
巨型框架减振结构具有调谐质量减振、基础隔震和阻尼耗能减振多种减振功能。文章采用隔震支座将主框架和子框架隔离开来,组成巨型框架减振结构;首先建立了巨型框架减振结构的结构动力模型得出减振结构运动方程,然后运用有限元分析软件SAP2000进行地震反应的线性时程分析,比较巨型框架减振结构和巨型框架抗震的动力响应;结果表明,减振结构方案有明显的减震效果。  相似文献   

10.
为了降低球罐结构的地震响应,对球形储罐进行基础隔震及附加耗能减震控制,建立了无控、隔震、耗能减震条件下球形储罐的有限元模型,并通过模态分析给出自振周期和频率。选择3种不同的地震波输入,进行了基础隔震结构及耗能减震结构地震响应时程分析。结果表明:基础隔震拉长了结构周期,达到了减震的目的,加速度反应降幅在41.4%~76.4%,相对位移反应降幅在50.3%~77.2%;附加的耗能装置的变形耗散了地震动能量,从而减小了结构自身的动力响应,加速度反应降幅在25.2%~77.9%,相对位移反应降幅在71.8%~76.7%;总体看球罐基础隔震结构优于附加耗能结构的减震效果。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
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。  相似文献   

15.
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.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
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-  相似文献   

20.
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-  相似文献   

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