共查询到18条相似文献，搜索用时 121 毫秒
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对现代无金属纤维混凝土结构和纤维砌块结构地磁观测室设计与建造技术，在天津徐庄子相对地磁观测室的应用研究进行了介绍，提出了这两种新型建筑结构的应用特点，及其关键技术要点，以及进一步发展复合碳纤维或玄武岩纤维，替代金属材料的若干观点和建议，对我国“十一五”小型地震监测台站的建设具有重要参考价值。 相似文献
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纤维增强复合材料（FRP）是近年来在结构工程中应用的一种新型材料，对纤维增强复合材料在结构抗震中的应用做了简要的回顾，最后，论述了开展纤维增强复合材料在结构抗震研究中的意义。 相似文献
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介绍了地震反应分析理论和方法发展的基本概况，并对弹塑性地震反应分析中采用的纤维梁柱单元及国外新近出现的IDA方法进行了详细的说明。在此基础上，对能够有效解决弹塑性地震反应分析计算的OpenSEES软件系统做了介绍。 相似文献
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纤维增强复合材料（Fiber Reinforced Polymer，简称"FRP"）具有轻质高强、耐腐蚀、耐疲劳和低导热系数等优点，现已广泛应用于土木工程各领域。针对FRP约束钢筋混凝土结构的抗爆性能，通过综述近年来国内外爆炸荷载下FRP约束钢筋混凝土结构动力响应的研究现状及进展，表明FRP材料的约束对钢筋混凝土结构的抗爆性能有显著的提高作用。此外，从相关理论研究、试验研究和数值模拟3个方面介绍了主要成果。针对现有成果，对爆炸荷载下FRP约束钢筋混凝土结构动力响应研究提出了需要进一步研究和解决的问题，可为后续研究提供一定的参考。 相似文献
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纤维增强材料对于改善水泥基材料的韧性和抗冲击性、大幅度提高混凝土的断裂能、防止混凝土发生脆性破坏具有重要意义;而"绿色"纤维在提高混凝土结构安全性的同时,具有环保、节能、利废、可降解再生等特性。本文介绍了"绿色"纤维的分类,分析了"绿色"纤维增强水泥基材料的特点,总结了"绿色"纤维在水泥基材料中应用、研究的进展。指出:"绿色"纤维与水泥基材料复合,适应循环经济和建材行业可持续发展的要求,是未来纤维增强水泥基复合材料发展的主要方向。 相似文献
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纤维模型中单元、截面及纤维划分问题研究 总被引：1，自引：0，他引：1
应用纤维模型进行结构弹塑性分析时,需要对单元、截面以及纤维进行划分,其划分结果对计算效率和精度有较大影响.基于有限元软件OpenSees中的3种非线性单元(DB、FB和PH单元),本文通过算例计算,对单元、截面以及纤维的划分问题进行了研究.结果表明,对于DB单元,建议一个构件划分为5个单元,单元内使用4个截面积分点,截面上使用6×6的纤维积分点；对于FB单元,建议一个构件用1个单元模拟即可,单元内使用4个截面积分点,截面上使用6×6的纤维积分点；对于PH单元,建议根据经验预设合理的塑性铰长度,截面上使用6×6的纤维积分点. 相似文献
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本文分别采用纤维单元模型和塑性铰单元模型对一个四层足尺钢框架振动台试验进行模拟分析,在三维空间非线性分析程序Perform-3D中进行动力非线性分析,比较分析结果,并与试验结果对比,以研究两种模型应用于钢框架整体结构非线性分析的计算精度。文中并讨论了纤维单元模型截面纤维的划分、塑性区长度的取值等问题。最后对采用组合梁的整体结构模型进行了动力非线性分析。结果表明,纤维模型的建模速度比塑性铰模型快,但塑性铰模型能模拟结构的倒塌时间。Perform-3D程序的纤维单元模型和塑性铰单元模型用于计算我国规范规定的7度和8度地震作用的多层钢框架结构,其结果是真实可靠的,而且计算结果偏于安全。 相似文献
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现代无金属地磁观测室建造试验研究 总被引：2，自引：1，他引：2
结合中国地震局地磁观测室建造的实际需要，利用美国赫氏公司的高科技碳纤维材料，进行了无磁复合碳纤维混凝土板承载力试验研究，介绍了试验研究的主要过程和试验分析结果，充分显示了纤维混凝土应用于地磁观测室建造的可行性和合理性。 相似文献
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光纤健康监测方法在土木工程中的研究与应用进展 总被引：25，自引：0，他引：25
在土木工程领域，光纤智能健康监测方法是对建筑物或构筑物的健康状况进行检测的一种新方法。本文首先论述了光纤智能健康监测系统的构成，然后对国内外光纤健康监测系统在土木结构中的研究与应用进行了回顾，介绍了光纤传感器的种类、原理、特点和当前应用的状况，重点介绍了光纤位移传感器和布拉格光栅（Bragg grating)应变传感器，最后展望了光纤智能健康监测方法在土木结构中的应用前景。 相似文献
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基于现代无金属结构设计理念,首次提出了平原地区玄筋混凝土沉井式结构立体地磁记录室设计研究方案,该方案较传统设计在地磁记录室温差控制能力方面有大幅度的提高,可以为记录仪器提供稳定的温度工作环境;真正实现了"地磁观测",地下深层空间观测可以有效的屏蔽地表及外空间的大量干扰因素,地磁台站占地面积可明显减小,该地磁观测室观测资料的质量将会产生飞跃。 相似文献
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Observations of bedload transport in a gravel bed river during high flow using fiber‐optic DTS methods 
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下载免费PDF全文 The question: ‘how does a streambed change over a minor flood?’ does not have a clear answer due to lack of measurement methods during high flows. We investigate bedload transport and disentrainment during a 1.5‐year flood by linking field measurements using fiber optic distributed temperature sensing (DTS) cable with sediment transport theory and an existing explicit analytical solution to predict depth of sediment deposition from amplitude and phase changes of the diurnal near‐bed pore‐water temperature. The method facilitates the study of gravel transport by using near‐bed temperature time series to estimate rates of sediment deposition continuously over the duration of a high flow event coinciding with bar formation. The observations indicate that all gravel and cobble particles present were transported along the riffle at a relatively low Shields Number for the median particle size, and were re‐deposited on the lee side of the bar at rates that varied over time during a constant flow. Approximately 1–6% of the bed was predicted to be mobile during the 1.5‐year flood, indicating that large inactive regions of the bed, particularly between riffles, persist between years despite field observations of narrow zones of local transport and bar growth on the order ~3–5 times the median particle size. In contrast, during a seven‐year flood approximately 8–55% of the bed was predicted to become mobile, indicating that the continuous along‐stream mobility required to mobilize coarse gravel through long pools and downstream to the next riffle is infrequent. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
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研究了基于纤维模型的CFT框架柱滞回性能模拟的建模方法,建立了基于不同材料本构模型的CFT框架柱数值模型,并探讨了材料本构关系、纤维截面网格划分、积分点数量等因素对模拟精度的影响。以试验为依据,运用Opensees软件,通过计算结果与试验结果的对比,分析了影响滞回模型计算精度的主要因素。结果表明,受约束混凝土本构关系的下降段,钢材本构关系的强化段,是影响滞回模型准确性的主要因素,而网格划分和积分点数量的影响则主要体现在程序运行速率方面。研究将为基于纤维模型法的CFT框架柱滞回性能模拟分析提供理论依据。 相似文献
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目前国内碳纤维复合材料气瓶的定期检验对于内部缺陷还没有成熟的无损检测方法,射线检测可以对内部缺陷进行定性检测,CT检测技术可实现缺陷的精确定位和定量。针对某型号呼吸器用碳纤维复合材料气瓶的结构特点,依据有关定期检验标准,制作各种缺陷,开展CT检测实验研究。结果表明该技术对表面缺陷和纤维层内部缺陷都有很好的检出效果。以厚度2姗的铝内胆为基础,对缺陷的位置和深度进行了估算。 相似文献
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In this paper, a fiber beam-column element considering flexure–shear interaction and bond-slip effect is developed for cyclic analysis of reinforced concrete (RC) structures. The element is based on conventional displacement-based Timoshenko beam theory, where the transverse shear deformation is included, and adopts the fiber model to describe the section force–deformation behavior. In the fiber model, shear deformation is assumed to be uniformly distributed along the section and is only resisted by concrete, thus the multi-dimensional concrete damage model is used for concrete fibers and therefore flexure–shear interaction is reflected naturally at the material level. Meanwhile, to account for the significant bond-slip effect at critical regions, the anchorage slip of bars at these regions is analytically derived. Then it is used to modify the uniaxial stress–strain model for steel fibers by assuming that the total strain can be treated as the sum of the bar deformation and anchorage slip, therefore the bond-slip effect is implicitly but simply represented. To validate the proposed element, a series of RC member and structure tests under cyclic loading are simulated. The results indicate that the proposed element can predict cyclic responses of RC structures, and can be used as a reliable tool for analysis of RC structures. 相似文献
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Comparison of fundamental properties of new types of fiber‐mesh‐reinforced seismic isolators with conventional isolators 下载免费PDF全文
下载免费PDF全文 New types of fiber‐reinforced rubber‐based seismic isolators have been a research interest for a number of engineers in the past decade. These new types of isolators can have similar seismic performances compared with the conventional ones. In most of the previous researches, the fiber‐reinforced rubber‐based isolators is usually manufactured with placing fiber sheets between precut rubber layers with the use of a bonding agent. This research differs from the previous researches in terms of manufacturing process, use of fiber mesh instead of fiber sheets, and use of lead in the core for some of the bearings. The aim of this research is to provide comparisons in fundamental seismic response properties of the new type of fiber mesh reinforced isolators and conventional isolators. In this scope, four pairs of fiber mesh reinforced elastomeric bearings and four pairs of steel‐reinforced elastomeric bearings are subjected to various levels of compression stresses and cyclic shear strains under constant vertical pressure. The tested types of isolators are fiber mesh reinforced elastomeric bearing, fiber mesh reinforced elastomeric bearing with lead core, steel‐reinforced elastomeric bearings, and steel‐reinforced elastomeric bearings with lead core. In this research, steel‐reinforced bearings are called conventional isolators. The major advantage for fiber mesh reinforced bearings observed during the tests is that these isolators can develop a considerable low horizontal stiffness compared with the conventional isolators. The damping characteristics of the new and conventional types are similar to each other. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献