共查询到20条相似文献，搜索用时 156 毫秒
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在强调结构实验技术对于土木工程学科发展重要性的前提下,结合作者在土木类实验室管理、振动台试验技术研究和虚拟实验中心建设中的若干经验,结合结构试验领域的科技发展动态,总结在远程混合试验、实时动力试验、虚拟仿真试验、智能化技术应用等结构试验领域的热点问题,对国内实验室建设和管理中设备选型、队伍建设和实验收费等问题进行了分析并给出解决方案,提出实用性建议。 相似文献
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隧道内双块式无碴轨道施工技术研究 总被引：1，自引：0，他引：1
介绍国内外无碴轨道的发展和应用现状,无碴轨道的结构组成和分类,以及双块式无碴轨道的结构和特点,着重总结隧道内双块式无碴轨道的施工技术和方法,供无碴轨道设计与施工参考. 相似文献
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为了确定加速度敏感型非结构构件振动台试验的输入,建立了用于非结构构件抗震性能检测的楼层反应谱,并开展了浮放输液架振动台试验验证该楼层反应谱的可用性.通过标准框架结构在不同地震强度下的弹塑性时程分析,确定非结构构件动力放大系数,基于分析结果建立了用于非结构构件抗震性能检测的楼层反应谱.利用该反应谱及其他现有检测楼层反应谱进行了浮放输液架的振动台试验,基于试验结果建立了不同输入下非结构构件的地震易损性曲线.提出的反应谱包括短周期段、上升段、平台段及下降段,平台段动力放大系数建议取值为3.0.试验结果表明,浮放输液架在0.307 4g的加速度输入下,即有50%的概率达到或超过500 mm的残余位移.提出的楼层反应谱可为振动台试验确定台面输入,用于非结构构件抗震性能检测,促进加速度敏感型非结构构件的抗震性能研究. 相似文献
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介绍了数字水印技术的产生过程及其特点:透明性、鲁棒性和安全性,比较了数字水印与密码学的差别,数字水印通过在数字信息产品中嵌入不可见信息来标识其所有者.分析了数字水印技术的现状,主要有两大类水印嵌入方法:基于空间域和基于变换域.根据水印传输载体的不同对数字水印在版权保护方面的应用进行了分类,基于对数字水印的学习研究,对数字水印技术的发展进行了展望,数字水印的应用领域将会越来越大. 相似文献
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振动台模型试验是研究大坝结构抗震性能的一项重要手段，相关的配套设备开发是提高试验水平的关键之一。本文首先介绍更新改进的振动台相关试验设备，包括数据采集系统、功率放大器和缝隙张开度测定仪器等。然后论述这些设备在动力模型试验中的实际应用。试验结果表明，这些更新改进的仪器设备在大坝动力模型试验中起到了重要作用。 相似文献
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孙瑶琴 《中国校外教育(理论)》2009,(7)
文章阐述了国内在基于内容的中文网页自动分类方面所做研究工作的发展现状,分析了已有工作的特点;在此基础上,结合自己的工作提出了一个基于内容的中文网页自动分类系统分析.给出了系统的总体结构设计思想和总体结构框架,以及组成系统的各个模块的功能和结构描述.按照该系统的设计思想和进一步的详细设计可以搭建一个系统化的、功能较为全面的、具有较高效率的中文网页自动分类系统平台. 相似文献
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孙善乾 《赤峰学院学报(自然科学版)》2007,23(1):48-49
本文介绍了切削技术及刀具发展现状以及未来应用先进切削技术时发展思路,重点介绍了高速切削等新工艺、硬质合金材料为主的各种刀具材料以及涂层成为提高刀具性能的关键技术、刀具结构的创新和快速发展的配套技术. 相似文献
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混凝土结构加固技术性能比较 总被引：3，自引：0，他引：3
李小利 《北京工业职业技术学院学报》2006,5(4):85-87
综合介绍了混凝土结构加固技术现状,对各种方法的特点和适用范围进行了比较,并对混凝土结构加固技术目前需要完善的地方以及发展方向提出了几点个人的看法,对于施工人员进行混凝土结构加固时进行适宜的方法选择具有一定的指导作用. 相似文献
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Shaking table test of pile-water-pier superstructure 总被引：1，自引：1，他引：0
The model test of seismic simulation shaking table is an important method to study the seismic design of bridge structure. In order to evaluate the seismic response and dynamic characteristics of pile-water-pier system for developing more reliable design procedures, shaking table model tests of a submerged bridge pier system, including pile groups-cap-pier and inertia mass, were conducted. Since different similitude laws corresponding to different test objectives affected the validity of test results, the similitude law with the aim to consider the effect of hydrodynamic pressure was proposed and confirmed through an actual example. Based on the test results, the effect of water around model on seismic response under seismic excitation input was analyzed and the failure level was judged by observing the variation of basic frequency. The test results indicate that the transfer function of analytical model with water is different from that without water, the natural frequency without water is always higher than that with water, and the first modal shapes are various. It is also concluded that the similitude law is suitable for practical application and the dynamic characteristics and seismic response of the structure system can be changed because of the existence of the surrounding water, which should be paid much attention in the further investigation. 相似文献
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INTRODUCTION Due to the increasing number of building story braced by transferring member during development of high or superhigh rise buildings, and the many de-mands and restrictions on floor height and space in architecture, it is necessary to use steel reinforced concrete (SRC) materials in transferring structure. SRC has high bearing capacity, good stiffness and relatively less section dimension, and ductility, dura-bility and aseismic behavior better than that of rein-forced concre… 相似文献
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The high-rise frame structure has become more and more widespread, like its damage from the complication of the environment. The traditional method of damage detection, which is only suitable for the stationary signal, does not apply to a high-rise frame structure because its damage signal is non-stationary. Thus, this paper presents an application of the short-time Fourier transform (STFT) to damage detection of high-rise frame structures. Compared with the fast Fourier transform, STFT is found to be able to express the frequency spectrum property of the time interval using the signal within this interval. Application of STFT to analyzing a Matlab model and the shaking table test with a twelve-story frame-structure model reveals that there is a positive correlation between the slope of the frequency versus time and the damage level. If the slope is equal to or greater than zero, the structure is not damaged. If the slope is smaller than zero, the structure is damaged, and the less the slope is, the more serious the damage is. The damage results from calculation based on the Matlab model are consistent with those from the shaking table test, demonstrating that STFT can be a reliable tool for the damage detection of high-rise frame structures. 相似文献
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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. 相似文献
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研究目的：创新要点：为多塔斜拉桥在一致激励和非一致激励下地震响应的研究提供地震模拟振动台全桥试验方法,并有助于加强多塔斜拉桥抗震性能和抗震设计的认识。1．建立了地震模拟振动台多台阵试验方法,并首次将其应用于多塔斜拉桥全桥比例缩尺模型的地震响应分析之中;2．通过地震模拟振动台试验,揭示了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性并提出了多塔斜拉桥在强震下的破坏模式。研究方法：1．基于动力相似理论,设计与制作了多塔斜拉桥的全桥比例缩尺模型（图2）;2．利用地震模拟振动台多台阵试验,根据在不同地震波作用下和考虑行波效应后多塔斜拉桥模型的主梁和主塔响应,分析了多塔斜拉桥在多点一致激励和多点非一致激励的地震响应特性（图5～图8）;3．根据在地震波不同强度作用下多塔斜拉桥模型的主梁和主塔响虚,分析了多塔斜拉桥在强震下的破坏模式和地震响应（图9）。重要结论：1．江心波作用下该多塔斜拉桥的地震响应大于其他三种地震波;2．多塔斜拉桥在抗震设计时需要考虑行波效应的影响;3．在El-Centro波的加速度峰值高达4．0m／s^2时,多塔斜拉桥模型出现了支座破坏。 相似文献
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Experimental Studies on High-Frequency Performance of the Inverse Control Magneto-Rheological Damper
Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological(MR) damper was designed to control the vibration. The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the parameters of the model keep stable in the ranqe of 15-50 Hz. 相似文献
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根据流砂形成的原因，一般的施工方法是通过降低地下水位来减小动水压力．控制流砂形成的原动力防治流砂。本论述了根据特定的施工地质条件从另一角度出发，不降水，而是在细砂中掺入一些粗砂、碎石等．改变砂土粒度级配来治理流砂。之后借助水撼等施工方法加固地基，同样会取得经济有放的结果。 相似文献
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A three-step damage identification method based on dynamic characteristics is proposed to improve the structure reliability and security and avoid serious accident. In the proposed method, the frequency and difference of modal curvature （DMC） are used as damage indexes. Firstly, the detection of the occurrence of damage is addressed by the frequency or the square of frequency change. Then the damage location inside the structure is measured by the DMC. Finally, with the stiffness reduction rate as a damage factor, the amount of damage is estimated by the optimization algorithm. The three-step damage identification method has been validated by conducting the simulation on a cantilever beam and the shaking table test on a submerged bridge. The results show that the method proposed in this paper can effectively solve the damage identification problem in theory and engineering practice. 相似文献
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中草药黄蜀葵的研究现状与展望 总被引：2，自引：0，他引：2
概述了近年来黄蜀葵生物学特性、栽培试验、化学成分、药理实验及新药开发的研究现状，并分析目前研究中存在的问题及今后的研究开发趋势，展望其可在研究和开发治疗缺血性心脏病和缺血性脑血管病等系列新药中取得重大的突破． 相似文献