Study on the severest real ground motion for seismic design and analysis

How to select the adequate real strong earthquake ground motion for seismic analysis and design of structures is an essential problem in earthquake engineering research and practice. In the paper the concept of the severest design ground motion is proposed and a method is developed for comparing the severity of the recorded strong ground motions. By using this method the severest earthquake ground motions are selected out as seismic inputs to the structures to be designed from a database that consists of more than five thousand significant strong ground motion records collected over the world. The selected severest ground motions are very likely to be able to drive the structures to their critical response and thereby result in the highest damage potential. It is noted that for different structures with different predominant natural periods and at different sites where structures are located the severest design ground motions are usually different. Finally, two examples are illustrated to demonstrate the rationality of the concept and the reliability of the selected design motion.

Ground support design for dynamic loading conditions:A quantitative data-driven approach based on rockburst case studies

There are considerable challenges associated with the design of ground support for seismically-active underground mines.It is extremely difficult to establish the demand on ground support as well as the capacity of a ground support system.The resulting dynamic or impact loads caused by mining-induced seismicity are difficult to anticipate and quantify.The performance of a ground support system is defined by the load distribution and interaction between several reinforcement and surface support elements.Consequently,the design of ground support in seismically-active mines tends to evolve,or be modified based on qualitative assessments of perceived performance or response to significant seismic events or rockbursts.This research is motivated by a need to provide quantitative and data-driven design guidelines for ground support systems subjected to dynamic-loading conditions.Rockburst data were collected from three deep and seismically-active underground mines in the Sudbury basin in Canada.The constructed database comprises 209 seismic events that resulted in damage to mine excavations and ground support.These events were associated with damage at 324 locations within the three mines.The developed ground support design strategy,based on these documented case studies,identifies areas where the use of dynamic or enhanced support should be employed.The developed design methodology provides guidelines for the zoning of mine locations in which installation of enhanced support is recommended,the specifications for an optimal ground support system,and the timing or sequence of installation.

Comparative Analysis of Equal and Unequal Grounding Grid Configurations by Compression Ratio and Least Square Curve Fitting Techniques

The primary aim of the power system grounding is to safeguard the person and satisfying the performance of the power systemtomaintain reliable operation.With equal conductor spacing grounding grid design,the distribution of the current in the grid is not uniform.Hence,unequal grid conductor span in which grid conductors are concentrated more at the periphery is safer to practice than equal spacing.This paper presents the comparative analysis of two novel techniques that create unequal spacing among the grid conductors:the least-square curve fitting technique and the compression ratio techniquewith equal grid configuration for both square and rectangular grids.Particle Swarm Optimization(PSO)is adopted for finding out one optimal feasible solution among many feasible solutions of equal grid configuration for both square and rectangular grids.Comparative analysis is also carried out between square and rectangular grids using the least square curve fitting technique as it results in only one unequal grid configuration.Simulation results are obtained by theMATLAB software developed.Percentage of improvement in ground potential rise,step voltage,touch voltage,and grid resistancewith variation in compression ratios are plotted.

Study on the Relationship of Seismic Design Ground Motion at Different Fortification Levels in the Xinjiang Region

The seismic risk analysis results of 79 cities in Xinjiang are presented, and the bedrock peak ground accelerations under three seismic levels and their ratios are discussed. Then, the relationship between earthquake environments and the seismic risk analysis results of different exceeding probabilities are researched. The results show that minor and major earthquake motion parameters calculated from moderate earthquakes do not have a consistent probability and the ratio of bedrock peak accelerations under different exceedance probabilities are closely correlated with earthquake environments.

Study on Site Specific Design Earthquake Ground Motion of Nuclear Power Plants in China

The main technical backgrounds and requirements are introduced with regard to earthquake ground motion design parameters in several domestic and American standards,codes and guides involved in the seismic analysis and design activities of nuclear power plants in China.Based on the research results from site seismic safety evaluation of domestic nuclear power plant projects in the last years,characteristics and differences of site specific design spectra are analyzed in comparison with standard response spectra,and the suitability of standard response spectra for domestic nuclear power plant projects is discussed.

Determination of horizontal and vertical design spectra based on ground motion records at Lali tunnel, Iran

Most acceleration diagrams show high levels of unpredictability, as a result, it is the best to avoid using diagrams of earthquake acceleration spect~＇a, even if the diagrams recorded at the site in question. In order to design earthquake resistant structures, we, instead, suggest constructing a design spectrum using a set of spectra that have common characteristics to the recorded acceleration diagrams at a particular site and smoothing the associated data. In this study, we conducted a time history analysis and determined a design spectrum for the region near the Lali tunnel in Southwestern Iran. We selected 13 specific ground motion records from the rock site to construct the design spectrum. To process the data, we first applied a base-line correction and then calculated the signal-to-noise ratio （]~SN） for each record. Next, we calculated the Fourier amplitude spectra of the acceleration pertaining to the signal window （1）, and the Fourier amplitude spectra of the associated noise （2）. After dividing each spectra by the square root of the selected window interval, they were divided by each other （1 divided by 2）, in order to obtain the ~SN ratio （filtering was also applied）. In addition, all data were normalized to the peak ground acceleration （PGA）. Next, the normalized vertical and horizontal responses and mean response spectrum （50%） and the mean plus-one standard deviation （84%） were calculated for all the selected ground motion records at 5% damping. Finally, the mean design spectrum and the mean plus-one standard deviation were plotted for the spectrums. The equation of the mean and the above-mean design spectrum at the Lali tunnel site are also provided, along with our observed conclusions.

Vertical-to-horizontal response spectral ratio for offshore ground motions:Analysis and simplified design equation

In order to study the differences in vertical component between onshore and offshore motions,the vertical-to-horizontal peak ground acceleration ratio(V/H PGA ratio) and vertical-to-horizontal response spectral ratio(V/H) were investigated using the ground motion recordings from the K-NET network and the seafloor earthquake measuring system(SEMS).The results indicate that the vertical component of offshore motions is lower than that of onshore motions.The V/H PGA ratio of acceleration time histories at offshore stations is about 50%of the ratio at onshore stations.The V/H for offshore ground motions is lower than that for onshore motions,especially for periods less than 0.8 s.Furthermore,based on the results in statistical analysis for offshore recordings in the K-NET,the simplified V/H design equations for offshore motions in minor and moderate earthquakes are proposed for seismic analysis of offshore structures.

中国本土卫浴陶瓷行业在中国风格设计转化过程中的技术路径探究

目的面向中国本土卫浴陶瓷行业,选取国内某龙头卫浴陶瓷企业的资深卫浴陶瓷设计师,探究中国风格在本土卫浴陶瓷设计转化过程中的设计层级及具体设计转化路径。方法在扎根理论的研究框架下,通过半结构深度访谈的形式对14名一线设计专家展开深度访谈,经过对原始资料的编码归纳、合并整理,结合该企业曾发售过的中国风格卫浴陶瓷实际案例来展开中国风格设计转化路径探究。结果最终得到包含中国风格卫浴陶瓷产品外观元素层、中国风格卫浴陶瓷产品及人的影响因素层、中国风格卫浴陶瓷产品深层文化观念层等三层设计转化路径,各层级内又包含不同的中国风格卫浴陶瓷具体设计手法。结论明确中国风格在卫浴陶瓷设计转化过程中的具体设计路径有助于本土卫浴陶瓷行业从更整体视角展开中国风格卫浴陶瓷的设计制造,通过三层设计路径的联动配合,进一步提升中国美学风格在卫浴陶瓷设计中的有效传达,增强中国本土卫浴陶瓷的核心竞争力和文化辨识度。

基于扎根理论的设计研究综述

近年来,学界应用扎根理论非常广泛,通过对扎根理论的起源、流派、研究方法进行梳理,分析扎根理论在设计中应用现状,并从质性、探索性、结构性等方面归纳扎根理论的基本特征,进一步拓展扎根理论在设计领域的应用广度与深度。运用文献研究法、归纳法、统计分析法探究扎根理论在设计学领域中的研究进展,提炼扎根理论在设计方面运用的启发性、程序性原理,以期为设计师更好地理解用户需求和行为,进行更精准的设计定位、指导设计实践提供参考。

高灵敏微波载荷卫星出舱电缆及舱体屏蔽的EMC设计

针对高灵敏微波载荷卫星对舱板电磁屏蔽效能的高需求与出舱电缆对舱体屏蔽效能巨大破坏性之间的矛盾,文章首先提出航天器理想舱板(无出舱电缆)的电磁屏蔽效能分析方法,给出提高对于1 GHz以上干扰电磁波屏蔽效能的设计原则;然后分析出舱电缆成为影响航天器外舱板对P波段(150 MHz~1 GHz)电磁波屏蔽效能主要因素的机理,给出干扰电流与干扰场强关系计算公式;最后给出出舱电缆及舱体屏蔽的电磁兼容(EMC)设计方法,提出用接地电阻测量法验证出舱电缆屏蔽皮接地的有效性,为总体总装EMC实施找到关键控制手段,并通过整星试验数据确认此方法能有效提升整星EMC试验效率。

基于扎根理论的智障儿童绘本设计策略研究

探究智障儿童绘本设计策略,为智障儿童绘本设计提供一个系统性的理论参照,助力智障儿童学习成长与康复。研究基于扎根理论,以《智障儿童无障碍学习全媒体出版工程》为例,采用网络数据采集,对数据进行编码分析,得出绘本设计的影响因素,并构建绘本设计影响因素模型。分析影响因素模型,指出智障儿童绘本设计受到视觉设计因素、传达设计因素和体验设计因素的影响,并提出对策建议。

地下结构抗震设计反应位移法的研究综述

近年来,反应位移法在地下结构抗震分析中的应用渐趋广泛。简要介绍了反应位移法的基本原理和应用现状,从地层变形、地基弹簧和结构模型等关键因素的角度详细总结了反应位移法的发展过程和最新研究进展,厘清了方法的完善思路,指出地层-结构相互作用是影响计算精度的重要误差来源。此外,在上述基础上论述了当前反应位移法应用过程中存在的突出问题,提出了反应位移法在进一步拓展应用场景、提升结果代表性过程中需要深入研究的关键问题。

Design of Ground Control Station for Operation of Multiple Combat Entities

Recently, if you look at the trend of the Unmanned Combat Entities (UCE) on the world that are actually operational, a large number of personnel per one UCE has been operating the GCS. However, UCEs to perform the attack/reconnaissance mission are very expensive assets and require a considerable amount of time to train for UCE operations. Accordingly, the future battlefield environment has become important to develop multiple UCE ground control station. In this study, we developed a multiple UCE GCS that one operator can operate up to four UCEs. The software was built with a total of 6 displays using a Lockheed Martin Corporation’s prepar3D. Scenario of research takes into account the operation of the South Korea-type future multiple UCEs, to take advantage of the simulation system, in this paper, we propose for each of the concepts and technologies.

远海岛礁与场地地震反应研究现状

本文从岛礁地质构造、岛礁地震反应数值模拟方法和岛礁场地效应等方面总结了海域岛礁地震反应的研究现状,对比并且分析了海域岛礁数值模拟方法中的流固耦合模拟方法、固体边界模拟方法和地震动输入方法;总结了现有海域岛礁地震反应的场地效应相关的研究成果。相关研究表明:海水对岛礁场地的放大系数有明显影响,岛礁表面砂层对水平向地震动加速度峰值放大显著,随着输入地震动峰值的增大,岛礁场地的PGA放大效应趋于减小;海域岛礁场地对中低频段的地震动反应较为显著,加速度峰值放大系数一般介于1.5到4.0之间。为满足岛礁工程的抗震设计,需要进一步解决岛礁工程合理地震动输入、岛礁场地地震反应规律与岛礁工程的设计地震动参数等关键科学问题。

一种分段的超短波对数周期天线设计与实验

超短波的传播方式主要为视距传播,这种传播方式需要天线具有强方向性且有较高的增益。而对数周期天线是一种超宽带、中等增益的天线,非常适用于超短波通信。然而在超短波频段下,常规对数周期天线的长度较长,小型化程度不高。为了实现超短波对数周期天线的小型化,提出一种分段的超短波对数周期天线的设计方案。根据应用需求,在满足天线增益的情况下,采用分段设计缩减天线长度,同时调整集合线之间的夹角,以实现天线的阻抗匹配。经过仿真设计,天线在30~70 MHz频段内典型增益大于8 dBi,天线的长度缩减至7 m。采用基于无人机飞行平台的外场测试系统对天线进行实验测试,测试结果表明,天线在工作频率范围内驻波比小于1.5,测试与仿真的辐射特性基本一致。该天线具有带宽宽、增益高、结构简单等特点,可以满足实际场景中超短波天线的需求。

咖啡渣材料在艺术设计领域中的应用研究综述

随着社会经济的迅速增长,人们赖以生存的环境正面临越来越多的生态挑战。在全球范围内,节能减排已成为共同的呼声,而探索新的生态友好材料成为解决环境问题的关键途径之一。因此,研究者们开始深入探究各种材料,寻找可持续资源。近年来,随着咖啡消费市场的持续增长,咖啡制作过程中产生的大量咖啡渣成为一种废弃资源。为了寻找新型材料的设计可能性,设计师们开始探索咖啡渣材料的新用途,使这种材料得到重新发掘和利用。文章分析了咖啡渣材料在艺术设计领域的创新应用,以期为材料设计提供新的研究方向。

基于扎根理论的社区环境设施微更新设计策略

在城市更新活动逐渐呈现出社区转向特征的背景下,研究社区环境设施微更新的策略框架与构成要素,旨在为社区环境设施的更新设计提供系统的指导,从而更好推动社区环境设施的可持续发展。基于扎根理论的研究方法,对社区环境设施设计的典型案例进行归纳性编码,提出“设施单体改造、环境氛围重塑、民本精神融入与社群协同管理”四个方面策略,为探究、分析与实施社区环境设施微更新提供了系统性的策略指导。

面向研究生群体的心理减压产品设计及实践研究

研究生群体心理健康问题日益突出,没有得到有效解决;探究心理减压产品的设计策略,为研究生群体减压产品设计提供支持。首先,应用文化探析法和扎根理论对研究生群体心理压力现状进行了解,运用情绪调节理论分析后,提出减压产品的用户需求;其次,运用AHP、QFD将用户需求转化为设计需求,最后,根据设计需求权重和相关性,提出功能与设计方法上的研究生群体减压产品设计策略。从情绪调节角度出发明确了研究生群体减压产品的用户需求;综合运用定性定量相结合的方法完成设计需求转化,基于此提出了以提高行动力为导向的功能化设计、以改善认知为导向的行为交互设计、以舒适和谐为导向的载体设计、以可持续性为导向的机制设计的4个设计策略,并设计1款面向研究生群体的减压产品原型。