Experimental performance evaluation of an equipment isolation using MR dampers     

Yu‐Cheng Fan  Chin‐Hsiung Loh  Jann N. Yang  Pei‐Yang Lin 《地震工程与结构动力学》2009,38(3):285-305

Critical non‐structural equipments, including life‐saving equipment in hospitals, circuit breakers, computers, high technology instrumentations, etc., are vulnerable to strong earthquakes, and the failure of these equipments may result in a heavy economic loss. In this connection, innovative control systems and strategies are needed for their seismic protections. This paper presents the performance evaluation of passive and semi‐active control in the equipment isolation system for earthquake protection. Through shaking table tests of a 3‐story steel frame with equipment on the first floor, a magnetorheological (MR)‐damper together with a sliding friction pendulum isolation system is placed between the equipment and floor to reduce the vibration of the equipment. Various control algorithms are used for this semi‐active control studies, including the decentralized sliding mode control (DSMC) and LQR control. The passive‐on and passive‐off control of MR damper is used as a reference for the discussion on the control effectiveness. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

汶川8．0级地震前电磁辐射异常变化特征初步研究   总被引：1，自引：0，他引：1  

丁跃军  陈化然  张建国 《地震地磁观测与研究》2009,30(3):11-15

汶川8．0级地震前,距离震中只有35km的金河电磁波台记录到了宝贵的电磁扰动信息。本文分析了汶川5．12大地震前后该台的电磁波异常变化特征,表明：①强震前确实有电磁辐射异常存在,震前存在丰富的电磁扰动信息;②电磁扰动前兆异常在时间进程上有明显的阶段性变化特征,这可能是地震孕育不同阶段特征的反映。  相似文献   

"5.12"汶川大地震公路路基震害浅析   总被引：2，自引：0，他引：2  

曾超  王可君  李曙平  王建国 《世界地震工程》2009,25(3)

通过对汶川地震重灾区高速公路及国省干线公路地震震害调查,介绍了四川绵阳地区公路路基震害基本情况,较为全面地总结了公路路基的震害特点,分析了震害与地层岩性、地质构造的内在关系,提出了路基病害整治的措施与建议.为灾后公路恢复重建工程的规划、勘察设计提供一定的参考.  相似文献   

基于大气污染控制的中国煤炭消费总量控制方案初步研究     

罗宏  张保留  吕连宏  裴莹莹 《气候变化研究进展》2016,12(3):172-178

控制煤炭消费是应对大气污染问题的关键措施,但中国煤炭消费总量控制仍未分解与落实到地方层面。研究基于大气污染的约束分析,结合情景分析与数据回归,通过建立大气污染物与煤炭消费之间的量化关系,分析了2020、2030年全国及各省/市煤炭消费总量控制目标,初步设计了中国煤炭消费总量控制方案,提出2020和2030年全国煤炭消费量控制目标分别为40亿t和45亿t,各省则均按预测结果调整执行,汇总值分别为44亿t和50亿t,鉴于两者之间的差距在于国家统计口径考虑了重复因素的剔除,故采纳基于国家统计数据的分析结果。建议构建绿色经济发展用煤指标,适当提高电力耗煤的比例,为促进中国中长期煤炭资源的合理消费提供科技支撑。  相似文献   

宁化—大田—惠安地壳构造与速度结构特征   总被引：5，自引：3，他引：2       下载免费PDF全文

蔡辉腾  金星  王善雄  李培  陈伟 《地球物理学报》2016,59(1):157-168

福建地处欧亚大陆东南缘,新构造活动强烈,区内北东向断裂带异常发育,是华南震区中、强地震活动的频发区.为深入认识我国东南沿海地壳上地幔速度结构特征及其深部构造背景,福建省地震局联合中国地震局地球物理勘探中心于2010年至2012年在福建陆域实施由18次人工爆破、四条北西向原生纵测线和四条北东向集成纵测线构成的三维人工地震测深实验.本文对该实验中以北西-南东走向近似垂直穿过政和—海丰断裂的宁化—大田—惠安深地震测深测线数据进行处理解释,采用地震射线走时正演构建了该剖面二维地壳速度模型.结果显示,沿剖面地壳厚度由西向东逐渐减薄,其西北侧地壳厚约31.8km,东南侧地壳厚达28.4km.剖面上地壳P波速度从5.90km·s~(-1)逐渐增加至6.20km·s~(-1),上地壳厚度横向变化不大,厚度在16~17km左右,但是下地壳厚度由西向东减薄较为明显.地壳以政和—海丰断裂为界,东西两段具有明显不同的速度结构,呈西段速度偏低、东段速度较高的特性,且西段在上下地壳分界面下方存在一个低速层.研究表明,剖面不同区段呈现出的速度结构差异与该区大地构造单元的划分基本吻合,剖面解释结果和以往远震接收函数研究结果均印证了作为闽西南坳陷带和闽东火山断陷带分界线的政和—海丰断裂是一条切割至下地壳底部的深大断裂.  相似文献   

Application of a perfectly matched layer in seismic wavefield simulation with an irregular free surface   总被引：2，自引：0，他引：2       下载免费PDF全文

Haiqiang Lan  Jingyi Chen  Zhongjie Zhang  Youshan Liu  Jianguo Zhao  Ruiqi Shi 《Geophysical Prospecting》2016,64(1):112-128

Recently, an effective and powerful approach for simulating seismic wave propagation in elastic media with an irregular free surface was proposed. However, in previous studies, researchers used the periodic condition and/or sponge boundary condition to attenuate artificial reflections at boundaries of a computational domain. As demonstrated in many literatures, either the periodic condition or sponge boundary condition is simple but much less effective than the well‐known perfectly matched layer boundary condition. In view of this, we intend to introduce a perfectly matched layer to simulate seismic wavefields in unbounded models with an irregular free surface. We first incorporate a perfectly matched layer into wave equations formulated in a frequency domain in Cartesian coordinates. We then transform them back into a time domain through inverse Fourier transformation. Afterwards, we use a boundary‐conforming grid and map a rectangular grid onto a curved one, which allows us to transform the equations and free surface boundary conditions from Cartesian coordinates to curvilinear coordinates. As numerical examples show, if free surface boundary conditions are imposed at the top border of a model, then it should also be incorporated into the perfectly matched layer imposed at the top‐left and top‐ right corners of a 2D model where the free surface boundary conditions and perfectly matched layer encounter; otherwise, reflections will occur at the intersections of the free surface and the perfectly matched layer, which is confirmed in this paper. So, by replacing normal second derivatives in wave equations in curvilinear coordinates with free surface boundary conditions, we successfully implement the free surface boundary conditions into the perfectly matched layer at the top‐left and top‐right corners of a 2D model at the surface. A number of numerical examples show that the perfectly matched layer constructed in this study is effective in simulating wave propagation in unbounded media and the algorithm for implementation of the perfectly matched layer and free surface boundary conditions is stable for long‐time wavefield simulation on models with an irregular free surface.  相似文献   

地下流体数据处理与产品加工软件系统设计     

刘春国  李正媛  王建国  张彬  樊春燕  陈华静 《中国地震》2014,30(2):260-271

在"十一·五"背景场探测项目"前兆数据处理软件系统"总体设计的框架下,以满足背景场项目完成后国家地下流体台网中心所有常规和应急产出产品的数据处理、加工制作需求为目标,对地下流体数据处理与产品加工软件系统的功能、处理模型与数据库结构进行了设计,并对主要的处理模型进行了测试。软件系统设计已经通过地下流体学科专家组的评审,被背景场项目实施组采纳。  相似文献   

新疆于田7.3级地震前瞻性预测回顾及其震后趋势分析          下载免费PDF全文

秦四清  薛雷  李培  李国梁 《地球物理学报》2014,57(2):679-684

基于作者提出的孕震断层多锁固段脆性破裂理论与相关预测方法,作者曾对于田地震区未来震情进行了前瞻性预测分析,给出了该地震区强（大）震事件的震级、震中经纬度、震源深度以及临界Benioff应变值四要素预测结果.将上述四要素预测结果与2014年2月12日新疆于田M_S7.3级地震参数进行比较,表明：四要素预测值与实际值相差不大,对于田地震区的前瞻性中长期预测结果可信.此外,本文认为2008年新疆于田—策勒M_L6.6级震群事件是2014年新疆于田7.3级地震发震的直接导火索.  相似文献   

极化方法在分析地磁秒数据异常信息中的应用     

刘奕君  张建国 《地震地磁观测与研究》2014,35(5):113-119

采用极化分析方法处理地磁秒数据.对不同台站地磁秒数据进行分析发现,极化值在地震发生前约2个月内有明显异常,且在傅里叶频谱上表现不太明显.另外,不同地磁分量的极化值映震效果不同,大部分震例极化值升高、振幅增大,小部分震例极化值低值、平稳.研究认为,该方法可以用于地磁秒数据震磁异常信息提取.  相似文献   

Poroelastic finite-difference modeling for ultrasonic waves in digital porous cores          下载免费PDF全文

Li-Yun Fu  Yan Zhang  Zhenglin Pei  Wei Wei  Luxin Zhang 《地震科学（英文版）》2014,27(3):285-299

Scattering attenuation in short wavelengths has long been interesting to geophysicists. Ultrasonic coda waves, observed as the tail portion of ultrasonic wavetrains in laboratory ultrasonic measurements, are important for such studies where ultrasonic waves interact with small-scale random heterogeneities on a scale of micrometers, but often ignored as noises because of the contamination of boundary reflections from the side ends of a sample core. Numerical simulations with accurate absorbing boundary can provide insight into the effect of boundary reflections on coda waves in laboratory experiments. The simulation of wave propagation in digital and heterogeneous porous cores really challenges numerical techniques by digital image of poroelastic properties, numerical dispersion at high frequency and strong heterogeneity, and accurate absorbing boundary schemes at grazing incidence. To overcome these difficulties, we present a staggered-grid high-order finite-difference (FD) method of Biot’s poroelastic equations, with an arbitrary even-order (2L) accuracy to simulate ultrasonic wave propagation in digital porous cores with strong heterogeneity. An unsplit convolutional perfectly matched layer (CPML) absorbing boundary, which improves conventional PML methods at grazing incidence with less memory and better computational efficiency, is employed in the simulation to investigate the influence of boundary reflections on ultrasonic coda waves. Numerical experiments with saturated poroelastic media demonstrate that the 2L FD scheme with the CPML for ultrasonic wave propagation significantly improves stability conditions at strong heterogeneity and absorbing performance at grazing incidence. The boundary reflections from the artificial boundary surrounding the digital core decay fast with the increase of CPML thicknesses, almost disappearing at the CPML thickness of 15 grids. Comparisons of the resulting ultrasonic coda Q _sc values between the numerical and experimental ultrasonic S waveforms for a cylindrical rock sample demonstrate that the boundary reflection may contribute around one-third of the ultrasonic coda attenuation observed in laboratory experiments.  相似文献