A study of energetics during an active monsoon over Indian region

The various forms of energy and energy conversions have been computed over a part of the Indian region during an active monsoon period, using the quasigeostrophic baroclinic model. The energetics of the monsoon depression have been discussed on the basis of these results.     

Assessment of liquefaction triggering using strain energy concept and ANN model: Capacity Energy

In the present study, an artificial neural network (ANN) model was developed to establish a correlation between soils initial parameters and the strain energy required to trigger liquefaction in sands and silty sands. A relatively large set of data including 284 previously published cyclic triaxial, torsional shear and simple shear test results were employed to develop the model. A subsequent parametric study was carried out and the trends of the results have been confirmed via some previous laboratory studies. In addition, the data recorded during some real earthquakes at Wildlife, Lotung and Port Island Kobe sites plus some available centrifuge tests data have been utilized in order to validate the proposed ANN-based liquefaction energy model. The results clearly demonstrate the capability of the proposed model and the strain energy concept to assess liquefaction resistance (capacity energy) of soils.     

Formulation of elastic earthquake input energy spectra

The object of this paper is to introduce a procedure for the determination of elastic design earthquake input energy spectra taking into account the influence of magnitude, soil type and distance from the surface projection of the fault. Firstly, an accurate selection of a large set of representative records has been realized. Secondly, the construction of the design input energy spectra has required determining the spectral shapes and a normalization factor which measures seismic hazard in terms of energy. This factor, denoted as the seismic hazard energy factor, has been defined as the area under the earthquake input energy spectrum in the period interval between 0·05 and 4·0 s. Finally, due to the importance of the source-to-site distance in the evaluation of the input energy, an investigation into the attenuation of the seismic hazard energy factor has been carried out. © 1998 John Wiley & Sons, Ltd.     

Design energy input spectra for moderate‐seismicity regions

This paper proposes energy input spectra applicable to seismic design of structures located in low‐to‐moderate‐seismicity regions. These spectra represent the load effect, in terms of input energy, of the most severe earthquake that the construction might encounter during its lifetime. The spectra have been derived through dynamic response analyses of over 100 ground motion records obtained from 48 earthquakes that have occurred in Spain. An empirical equation for estimating the energy input contributable to damage from the total input energy is also suggested. This equation takes into account both the damping and the degree of plastification of the structure. Finally, the proposed design energy input spectra are compared with the provisions of the current Spanish Seismic Code and with the response spectra of recent earthquakes that have occurred in Turkey and Taiwan. Copyright © 2002 John Wiley & Sons, Ltd.     

Divergent-rotational Nonlinear Energy Conversions in Wavenumber-frequency Domain During Summer Monsoon

--This work deals with computational modelling designed to understand the dynamical mechanism of low frequency monsoonal transients that results from nonlinear divergent-rotational (&gif1;) kinetic energy (KE) conversions due to the effects of Coriolis force, vorticity and divergence during the summer monsoon 1988 over the latitudinal belt 20°S-30°N at 850 hPa and 200 hPa. The results show two distinct spectral peaks spanning 30-45 days and 18-25 days in the energy conversions from the transient divergent motions to rotational motions. Due to the latitudinal variation of the earth's rotational effects, the conversion from the transient divergent to rotational motions, associated mainly with wavenumbers 1 and 2, tend to be more pronounced to the north of 15°N on the 30-45-day and 18-25-day time scales in the upper and lower tropospheres, respectively. The contribution of the stationary waves to maintenance of the low frequency rotational flow due to the effect of divergence through barotropic instability is significant at the upper troposphere. Divergent to rotational KE conversion by wave-wave interaction due to divergence is identified as an important mechanism for maintenance of low frequency oscillations in the lower troposphere. The upper tropospheric planetary scale divergent motions associated with 30-45-day oscillation gain substantial energy through nonlinear &gif1; interaction due to vorticity.     

Ms8.0汶川地震断层的应力状态以及对余震危险性的影响

利用中国地震局在汶川地震前后对四川盆地以及龙门山断裂进行的水压致裂绝对应力测量数据、近断层强震记录、以及由美国USGS公布的包括地震矩和地震波能量等在内的远场震源参数解,从简单断层模型出发,应用地震能量分配原理和库仑摩擦准则,初步估算和判断了2008年Ms8.0汶川地震断层破裂过程和震源参数,以及滑移弱化模型下应力变化...     

两种弧形钢阻尼器设计与性能研究

本文利用钢塑性滞回变形耗能的特性,提出了两种弧形钢耗能阻尼器,通过分析得出该阻尼器的设计公式,并建立了相应的力学模型.为验证两种弧形钢阻尼器的力学特性,进行了数值仿真和试验测试,并对比分析两种方法得到的结果.结果表明:弧形钢阻尼器具有较高的阻尼比和稳定的滞回特性,可以作为减震结构在桥梁、建筑领域推广应用.     

沙漠绿洲地区夏季地表能量收支的数值模拟

本文在MSPAS(Modified Soil-Plant-Atmosphere Scheme)的基础上,引入了一个有效的晴天大气辐射传输方案,建立了一个能在物理上真实地模拟陆气相互作用及其反馈机制的二维模式MLAIM（Modified Land Atmosphere Interaction Model）.本文利用HEIFE实验的观测资料对MLAIM的模拟结果进行了检验,对其中不合理的部分进行了分析,指出了在干旱半干旱区陆面过程参数修正的必要性,对干旱半干旱区土壤水分传输以及大气近地面层湍流输送的参数化方案进行了改进.改进后的模式能够较好地模拟夏季连续晴天条件下沙漠的地表能量收支,因此,本文利用MLAIM研究了绿洲对其周围沙漠地表能量收支的影响,并对地表能量收支各分量之间的相互作用进行了分析.结果表明,绿洲向其下风向沙漠的水汽输送是导致其上下风向沙漠间地表能量收支差异的最重要的因子.     

支撑刚度对磁摩擦耗能减振体系的影响

本文在已有磁摩擦耗能减振体系振动台试验基础上，讨论了两类磁摩擦耗能减振体系支撑刚度的影响，揭示了支撑刚度对磁摩擦耗能装置减振效果的影响规律，给出了两类磁摩擦耗能装置在结构中发挥最佳减振效果时支撑刚度的取值范围。     

表层沉积物特性对地震地面运动的影响研究

建立包含震源、沉积盆地和表层低速沉积层的二维模型,采用交错网格有限差分/伪谱混合方法求解地震波传播,讨论沉积层厚度和速度对地震地面运动的作用。结果表明:沉积层内产生的地震波的多重反射以及转换会引起地面运动持续时间的延长,它们的相干叠加会造成地面运动峰值的放大;随着沉积层速度的增加,多重反射与转换波的能量减小,地面运动持续时间减小,但是不同速度或者不同厚度的低速层模型均显示出一致的地面运动峰值放大特征。结果说明,在包含震源、沉积盆地和沉积层的模型中,沉积层对地面运动的作用机理更复杂。在实际应用中有必要同时考虑这些因素的综合作用。     

改善钢筋混凝土低矮剪力墙抗震性能的研究

普通钢筋混凝土低矮剪力墙抗震性能较差，其抗震性能的改善一直受到工程界的关注。总结了一些改善低矮剪力墙抗震性能的国内外研究成果，包括：开缝低矮剪力墙、带暗支撑低矮剪力墙、设耗能装置的低矮剪力墙和低矮组合剪力墙等。在此基础上，提出了一种新型耗能剪力墙，并进行了初步的试验研究。     

储层流体识别的新方法

利用小波变换方法可以把原始信号分解为一系列载有不同信息的子信号,每种子信号载有储层的特定信息,包括流体、岩性和孔隙结构等。我们开发出了基于小波变换的谱分析方法,利用该方法可以从这些子信号中提取出反映地层流体特性的子信号,通过对该子信号的处理识别出地层所含流体的特性。本文利用该流体识别新方法对某油田的实际测井资料进行了处理,处理结果与试油结果符合得很好,进一步证明了本方法的可靠性和实用性。     

The seismic energy of Yaoan earthquake sequence estimated by peak velocity

For a long time, a quantitative calculation of energy radiated by seismic waves has been an important problem in the basic study of seismology. Up to now the well-known relationship of lgE=l.5MS+11.8 created by Gutenberg and Richter (1956) has still been a better experiential statistical relation for estimating the energy of seismic waves. Since the creation of seismic dislocation model in the 1960s, seismologists have studied a quantitative calculation of energy radiated by seismic waves. F…     

摩擦耗能器的类型与性能及其在实际工程中的应用

摩擦耗能器是一种构造简单、耗能机理明确、耗能能力大且性能稳定的耗能减震装置,在实际工程中已得到较为广泛的应用.主要介绍不同类型摩擦耗能器的构造与性能及其在实际工程中的应用,并提出了摩擦耗能器在开发与应用中需进一步研究解决的问题.     

低周反复荷载作用下复合耗能支撑钢筋混凝土框架结构的抗震性能试验研究

本文介绍了三榀钢支撑钢筋混凝土框架结构（包括两榀复合耗能支撑框架、一榀普通支撑框架）在低周反复荷载作用下的试验结果。对复合耗能支撑框架结构在低周反复荷载作用下的工作性能（包括受力性能、破坏形态、滞回曲线、骨架曲线、延性和耗能能力等）进行了探讨,揭示了复合耗能支撑框架结构良好的抗震性能。     

Earthquake‐resistant structural design through energy demand and capacity

An energy‐based earthquake‐resistant structural design method is proposed. The proposed method uses specific input energy spectra, modal or time‐history analyses, and energy distribution among structural members. For a given member strength and stiffness, a relationship between the energy attributable to damage absorbed by a member and its cumulative ductility demand can be determined. Member strength, stiffness and energy capacity are design parameters which are simultaneously used in the design. The method can avoid soft‐storey design. The damage is measured based on a cumulative basis considering earthquake magnitude, frequency, and duration. Tests have been carried out to determine energy absorbing capacities of various structural components. More efforts are needed to make the energy‐based earthquake‐resistant structural design practical, but ssimple formulations for this method are possible. Copyright © 2007 John Wiley & Sons, Ltd.     

公路简支梁桥的地震能量响应分析

利用有限元软件SAP2000建立了某公路简支梁桥的有限元模型,以7条典型强震记录为输入,研究了公路简支梁桥的地震能量响应及其分配规律。结果表明:①地基柔性效应对公路简支梁桥的地震能量响应及其分配规律的影响较小;②当场地土质变软时,地震总输入能、结构阻尼耗能和结构阻尼耗能比均呈递增趋势,而结构滞回耗能和结构滞回耗能比则不断减小,即地基土体作为桥梁动力系统的一部分,增大了系统阻尼,并分担了部分非弹性变形;③随着PGA增大,输入结构的地震能量也增加,导致塑性铰的非弹性变形增加,即结构滞回耗能和结构阻尼耗能增大。     

单自由度自复位体系设计能量谱研究

本文对具有旗帜型滞回模型的单自由度自复位体系提出了设计能量谱的构造方法,包括设计输入能量谱和设计滞回耗能比谱。首先按中国规范场地类别选取360条实际强震记录进行时程分析,对影响单自由度自复位体系输入能量谱和滞回耗能比谱的参数,包括地震波类型、滞回模型、阻尼比、延性系数等进行研究。在此基础上分别建议了设计输入能量谱和设计滞回耗能比谱及其曲线参数的确定方法,并与实际强震记录计算结果进行比较。结果表明结构滞回模型对能量谱影响明显;阻尼比和延性系数对输入能量谱的影响在整个周期范围内有显著差异,但均有明显的削峰作用。建议的两种设计能量谱综合考虑了结构参数、地震波参数和中国场地类别的影响,可以较好的拟合实际情况,并对弹塑性单自由度自复位体系在地震作用下的耗能需求做出较准确的估计。     

Damage index based on stiffness degradation of low‐rise RC walls

Widely used damage indices, such as ductility and drift ratios, do not account for the influences of the duration of strong shaking, the cumulative inelastic deformation or energy dissipation in structures. In addition, the formulation and application of most damage indices have until now been based primarily on flexural modes of failure. However, evidence from earthquakes suggests that shear failure or combined shear‐flexure behavior is responsible for a large proportion of failures. Empirical considerations have been made in this paper for evaluating structural damage of low‐rise RC walls under earthquake ground motions by means of a new energy‐based low‐cycle fatigue damage index. The proposed empirical damage index is based on the results of an experimental program that comprised six shake table tests of RC solid walls and walls with openings; results of six companion walls tested under QS‐cyclic loading were used for comparison purposes. Variables studied were the wall geometry, type of concrete, web shear steel ratio, type of web shear reinforcement, and testing method. The index correlates the stiffness degradation and the destructiveness of the earthquake in terms of the duration and intensity of the ground motions. The stiffness degradation model considers simultaneously the increment of damage associated to the low‐cycle fatigue, energy dissipation, and the cumulative cyclic parameters, such as displacement demand and hysteretic energy dissipated. Copyright © 2014 John Wiley & Sons, Ltd.