结构被动耗能减振效果的参数影响   总被引：58，自引：6，他引：52  

欧进萍  吴斌  龙旭 《地震工程与工程振动》1998,18(1):60-70

本文研究粘滞、粘弹、金属屈服和摩擦型上类与斜撑串联的被动耗能器对结构减振效果的参数影响。首先,建立了结构、耗能器和斜撑共同工作的计算模型;然后考虑不同耗能器的特点,给出了相应的运动方程;第三,通过大量的数值计算,研究了耗能器刚度（或耗能器与斜撑的组合刚度）、屈服位移等参数对结合减振结果的影响,得到了这些参数的最佳取值范围,从而为结构的耗能减振设计提供了基础。  相似文献   

Simulating study on barchan dune     

凌裕泉  吴正  刘绍中  李长治 《中国地理科学(英文版)》1998,8(2):168-175

ＳＩＭＵＬＡＴＩＮＧＳＴＵＤＹＯＮＢＡＲＣＨＡＮＤＵＮＥ①ＬｉｎｇＹｕｑｕａｎ（凌裕泉）１ＷｕＺｈｅｎｇ（吴正）２ＬｉｕＳｈａｏｚｈｏｎｇ（刘绍中）３ＬｉＣｈａｎｇｚｈｉ（李长治）１１ＩｎｓｔｉｔｕｔｅｏｆＤｅｓｅｒｔＲｅｓｅａｒｃｈ,ｔｈｅＣｈｉｎ...  相似文献   

Dynamic Mechanism of Migmatization in the Dabie Complex,Northeastern Hubei,China1     

Wang Jianghai  Yang Wenhua  Wu Jinping 《《地质学报》英文版》1995,8(2):135-154

Abstract On the basis of the detailed field work, compositions and contents of plagioclase and K-feldspar, determination of ordering degree, statistical analysis of plagioclase elongation index, mass-balance calculation and mineral spatial distribution and geochemistry, it is concluded that the migmatites in the Dabie complex are characterized by the presence of thermocenters. There are regular changes in mineral character in the migmatites from the centers outwards. The dominant genetic mechanism is anatexis and metasomatism, whose intensities decrease from the centers outwards. Finally, according to the simulated experiment on Liesegang' s rings and non-linear dynamics (dissipative structure theory), the dynamic mechanism of migmatization is profoundly expouded as consisting of the early-stage metasomatism induced by the thermal anomaly, the cardinal-stage anatexis induced by the early-stage matasomatism and finally the last-stage post-anatexis metasomatism.  相似文献   

非线性耗散方程Cauchy问题广义解     

梅茗 《华东地质学院学报》1989,12(3):93-100

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3-D rheologic model of earthquake preparation (Ⅱ):Strain field and its applications     

宋治平  尹祥础  梅世蓉 《地震学报(英文版)》2004,17(2)

On the basis of the three-dimensional elastic inclusion model, the analytic expression of viscoelastic strain field is derived, i.e., the analytic expression of viscoelastic strain at an arbitrary point (x, y, z) in x-axis, y-axis and z-axis produced by three-dimension inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model, namely the normal strains εxx(r, t), εyy(r, t) and εzz(r, t), the shear strains εxy(r, t) and εyx(r, t), εyz(r, t)and εzy(r, t), εxz(r, t) and εzx(r, t), and the bulk-strain θ (r, t). By computing the spatial-temporal variation of bulk strain on the ground produced by a spherical rheologic inclusion in a semi-infinite rheologic medium, we obtained some significant results that the bulk-strain variation with time produced by a hard inclusion has three stages (α, β,γ) with different characteristics, which are similar to those of most geodetic deformation curves, but not the case for those by a soft inclusion. It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial-temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short-term and imminent-term precursors. It offers a theoretical base to found the physical model of earthquake precursors and a reference to predict physically the earthquakes.  相似文献   

3-D rheologic model of earthquake preparation (I) — Displacement field     

Song Zhi-ping  Yin Xiang-chu  Mei Shi-rong 《地震学报(英文版)》2003,16(6):588-597

Based on the three-dimensional ela stic inclusion model proposed by Dobrovolskii, we developed a three-dimensional rheologic inclusion model and theory to study the earthquake preparation process. By using correspondence principle in the theory of rheologic mechanics, we derived the analytic expression of the viscoelastic displacement at an arbitrary point (x, y, z) in three directions of x, y and z-axes (i.e., U(r, t), V*(r, t) and W(r, t)) produced by a three-dimension inclusion in the semi-infinite rheologic medium defined by the standard linear rheologic model. Foundation item: Chinese Joint Seismological Science Foundation (101105)  相似文献   

支撑刚度对磁摩擦耗能减振体系的影响   总被引：1，自引：0，他引：1  

王伟  刘振鹏  李庆祥 《地震工程与工程振动》2003,23(3):170-176

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。  相似文献   

Temporal and spatial variations of post-seismic deformation following the 1999 Chi-Chi, Taiwan earthquake     

Ya-Ju Hsu  Paul Segall  Shui-Beih Yu  Long-Chen Kuo  Charles A. Williams 《Geophysical Journal International》2007,169(2):367-379

We use GPS displacements collected in the 15 months after the 1999 Chi-Chi, Taiwan earthquake  ( M _w 7.6)  to evaluate whether post-seismic deformation is better explained by afterslip or viscoelastic relaxation of the lower crust and upper mantle. We find that all viscoelastic models tested fail to fit the general features in the post-seismic GPS displacements, in contrast to the satisfactory fit obtained with afterslip models. We conclude that afterslip is the dominant mechanism in the 15-month period, and invert for the space–time distribution of afterslip, using the Extended Network Inversion Filter. Our results show high slip rates surrounding the region of greatest coseismic slip. The slip-rate distribution remains roughly stationary over the 15-month period. In contrast to the limited coseismic slip on the décollement, afterslip is prominent there. Maximum afterslip of 0.57 m occurs downdip and to the east of the hypocentral region. Afterslip at hypocentral depths is limited to the southern part of the main shock rupture, with little or no slip on the northern section where coseismic slip was greatest. Whether this results from along strike variations in frictional properties or dynamic conditions that locally favour stable sliding is not clear. In general, afterslip surrounds the area of greatest coseismic slip, consistent with post-seismic slip driven by the main shock stress change. The total accumulated geodetic afterslip moment is  3.8 × 10¹⁹ N m  , significantly more than the seismic moment released by aftershocks,  6.6 × 10¹⁸ N m  . Afterslip and aftershocks appear to have different temporal evolutions and some spatial correlations, suggesting that aftershock rates may not be completely controlled by the rate of afterslip.  相似文献   

Construction of constant-Q viscoelastic model with three parameters   总被引：1，自引：0，他引：1  

孙成禹  印兴耀 《地震学报(英文版)》2007,(4)

The popularly used viscoelastic models have some shortcomings in describing relationship between quality factor (Q) and frequency, which is not consistent with the observation data. Based on the theory of viscoelasticity, a new approach to construct constant-Q viscoelastic model in given frequency band with three parameters is developed. The designed model describes the frequency-independence feature of quality factor very well, and the effect of viscoelasticity on seismic wave field can be studied relatively accurate in theory with this model. Furthermore, the number of required parameters in this model has been reduced fewer than that of other constant-Q models, this can simplify the solution of the viscoelastic problems to some extent. At last, the accuracy and application range have been analyzed through numerical tests. The effect of viscoelasticity on wave propagation has been briefly illus-trated through the change of frequency spectra and waveform in several different viscoelastic models.  相似文献   

Reflection/transmission laws for slowness vectors in viscoelastic anisotropic media     

V. Červený 《Studia Geophysica et Geodaetica》2007,51(3):391-410

The reflection/transmission laws (R/T laws) of plane waves at a plane interface between two homogeneous anisotropic viscoelastic (dissipative) halfspaces are discussed. Algorithms for determining the slowness vectors of reflected/transmitted plane waves from the known slowness vector of the incident wave are proposed. In viscoelastic media, the slowness vectors of plane waves are complex-valued, p = P + iA, where P is the propagation vector, and A the attenuation vector. The proposed algorithms may be applied to bulk plane waves (A = 0), homogeneous plane waves (A ≠ 0, P and A parallel), and inhomogeneous plane waves (A ≠ 0, P and A non-parallel). The manner, in which the slowness vector is specified, plays an important role in the algorithms. For unrestricted anisotropy and viscoelasticity, the algorithms require an algebraic equation of the sixth degree to be solved in each halfspace. The degree of the algebraic equation decreases to four or two for simpler cases (isotropic media, plane waves in symmetry planes of anisotropic media). The physical consequences of the proposed algorithms are discussed in detail. vcerveny@seis.karlov.mff.cuni.cz  相似文献