用于RC框架-轻钢增层混合结构的新型外箍式节点抗震性能试验研究

RC框架-轻钢增层混合结构是一种上轻下重、刚度突变明显的复杂结构,为了保证结构整体协同工作,本文提出了一种能够有效减缓刚度突变和增强对上部结构约束的新型外箍式连接节点。通过对新型外箍式节点与传统植筋节点的1∶2缩尺模型拟静力试验研究,得到了试件破坏模式和荷载-位移滞回曲线,对比分析了其滞回特性、梁端塑性铰、骨架曲线、强度退化、刚度退化和耗能能力等抗震性能。结果表明:新型外箍式节点可以使梁端塑性铰远离梁根部,有效保护了节点核心区;新型节点通过外箍钢板的构造措施提高了试件的初始刚度、承载力和耗能能力,减缓了刚度与强度退化速度,表明新型节点的抗震性能大幅度优于传统植筋节点,研究成果可为RC框架-轻钢增层混合结构的节点设计提供一定参考。     

EXPERIMENTAL STUDY OF SEISMIC PERFORMANCE OF SECTION STEEL-STEEL PLATE CONCRETE COMPOSITE WALL1)

提出一种型钢-钢板混凝土组合墙,为了研究其抗震性能,设计制作该形式的型钢-钢板混凝土组合墙进行拟静力试验。通过改变试件的轴压比、剪跨比,研究其在低周往复载荷作用下的受力机理、滞回性能、刚度退化及耗能能力等。试验结果表明：试件的破坏形态为压弯破坏,组合墙两端方钢管正面及侧面发生撕裂,两侧底部钢板屈曲严重,混凝土压溃;随着轴压比减小,试件具有更好的塑性变形能力和耗能能力,剪跨比对组合墙的抗震性能影响较小。     

数学物理中的总体和局部场GL方法

为了求解物理化学生物材料和金融中的微分方程,提出了一种总体(Global)和局部(Local)场方法.微分方程的求解区域可以是有限域,无限域,或具曲面边界的部分无限域.其无限域包括有限有界不均匀介质区域.其不均匀介质区域被分划为若干子区域之和.在这含非均匀介质的无限区域,将微分方程的解显式地表示为在若干非均匀介质子区域上和局部子曲面的积分的递归和.把正反算的非线性关系递归地显式化.在无限均匀区域,微分方程的解析解被称为初始总体场.微分方程解的总体场相继地被各个非均匀介质子区域的局部散射场所修正.这种修正过程是一个子域接着另个子域逐步相继地进行的.一旦所有非均匀介质子区域被散射扫描和有限步更新过程全部完成后,微分方程的解就获得了.称其为总体和局部场的方法,简称为GL方法.GL方法完全地不同于有限元及有限差方法,GL方法直接地逐子域地组装逆矩阵而获得解.GL方法无需求解大型矩阵方程,它克服了有限元大型矩阵解的困难.用有限元及有限差方法求解无限域上的微分方程时,人为边界及其上的吸收边界条件是必需的和困难的,人为边界上的吸收边界条件的不精确的反射会降低解的精确度和毁坏反算过程.GL方法又克服了有限元和有限差方法的人为边界的困难.GL方法既不需要任何人为边界又不需要任何吸收边界条件就可以子域接子域逐步精确地求解无限域上的微分方程.有限元和有限差方法都仅仅是数值的方法,GL方法将解析解和数值方法相容地结合起来.提出和证明了三角的格林函数积分方程公式.证明了当子域的直经趋于零时,波动方程的GL方法的数值解收敛于精确解.GL方法解波动方程的误差估计也获得了.求解椭圆型,抛物线型,双曲线型方程的GL模拟计算结果显示出我们的GL方法具有准确,快速,稳定的许多优点.GL方法可以是有网,无网和半网算法.GL方法可广泛应用在三维电磁场,三维弹塑性力学场,地震波场,声波场,流场,量子场等方面.上述三维电磁场等应用领域的GL方法的软件已经由作者研制和发展了。     

基于修正的Clough-Penzien地震动模型时MTMD的动力特性

研究了由许多刚度和阻尼保持常量而频率呈线性分布的TMD形成的MTMD的地震特性，基于虚拟激励法和本文提出的平稳过滤有色噪声地震动模型（修正的Clough-Penzien地震动模型），建立了结构－MTMD系统的传递函数，进而导出了设置MTMD时结构的动力放大系数（DMF）明确表达式。MTMD的优化准则可选为最大动力放大系数的最小值的最小化（Min.Min.Max.DMF)。通过最优搜寻可得MTMD的最优频率间隔、平均阻尼比、调谐频率比和相应的无量纲控制有效性指标。考虑结构受控频率与场地土卓越频率比的不同取值和不同场地类型，研究了场地土卓越频率和场地类型对MTMD最优参数及有效性的影响。而且，为比较，基于Clogh-Penzien地震动模型和不考虑地震动模型的结果也被考虑。     

基于子结构法的土-地下空间结构体系地震反应高效计算系统研究

为研发适用于土-地下空间结构相互作用体系地震反应分析的高效计算系统，本文基于子结构方法，综合利用ABAQUS软件和SASSI 2010的各自优势，通过二次开发，构建了一个适于土-地下空间结构动力相互作用分析的高效计算系统(ABAQUS-SASSI 2010 Combined System，简称ASCS)．该计算系统实现了ABAQUS软件和SASSI 2010的无缝连接，用户可以按照ABAQUS软件的可视化前处理功能，方便地建立包括土-地下空间结构相互作用体系在内的各种有限元模型，并调用和执行SASSI 2010程序的不同模块，按子结构方法对整个体系实施高效计算．为验证ASCS计算系统的有效性，文中首先采用ASCS计算系统对日本阪神地震中大开地铁车站的震害进行了模拟；然后，采用ABAQUS软件建立土-大开地铁车站结构相互作用体系的整体有限元分析模型，通过对比分析ASCS计算系统的子结构法结果和ABAQUS软件的整体有限元法结果，进一步验证了ASCS计算系统的计算精度和效率．结果表明：基于本文ASCS计算系统的数值模拟结果与阪神地震中大开地铁车站的震害结果一致；ASCS计算系统的子结构法结果与整体有限元法结果基本吻合，但前者的CPU时间是后者的1/21，明显提高了计算效率．     

Low-Frequency Asymptotic Analysis of Seismic Reflection from a Fluid-Saturated Medium

Reflection of a seismic wave from a plane interface between two elastic media does not depend on the frequency. If one of the media is poroelastic and fluid-saturated, then the reflection becomes frequency-dependent. This paper presents a low-frequency asymptotic formula for the reflection of seismic plane p-wave from a fluid-saturated porous medium. The obtained asymptotic scaling of the frequency-dependent component of the reflection coefficient shows that it is asymptotically proportional to the square root of the product of the reservoir fluid mobility and the frequency of the signal. The dependence of this scaling on the dynamic Darcy’s law relaxation time is investigated as well. Derivation of the main equations of the theory of poroelasticity from the dynamic filtration theory reveals that this relaxation time is proportional to Biot’s tortuosity parameter.     

Analytic hierarchy based policy design method (AHPo) for solving societal problems that require a multifaceted approach

This paper proposes an AHP based statistical method for the design of a comprehensive policy alternative, AHPo, for solving societal problems that require a multifaceted approach. In the proposed method, criteria relevant to the goal or focus are structured in the same way as in the conventional AHP. However, these two methods are quite different in regard to the method of quantification. The new method predicts or analyses the impact of the policy alternatives on the overall goal. In other words, it predicts or rationalizes the way people appreciate the situation in which an alternative is adopted and implemented. It will serve as a tool for supporting (especially political) decision making.     

Subspace modelling for structured noise suppression

The problem of structured noise suppression is addressed by (i) modelling the subspaces hosting the components of the signal conveying the information and (ii) applying a nonlinear non-extensive technique for effecting the right separation. Although the approach is applicable to all situations satisfying the hypothesis of the proposed framework, this work is motivated by a particular scenario, namely, the cancellation of low frequency noise in broadband seismic signals.     

A Boolean Delay Equation Model of Colliding Cascades. Part I: Multiple Seismic Regimes

We consider a prominent feature of hierarchical nonlinear (complex) systems: persistent recurrence of abrupt overall changes, called here critical transitions. Motivated by the earthquake prediction problem, we formulate a model that uses heuristic constraints taken from the dynamics of seismicity. Our conclusions, though, may apply to hierarchical systems that arise in other areas.We use the Boolean delay equation (BDE) framework to model the dynamics of colliding cascades, in which a direct cascade of loading interacts with an inverse cascade of failures. The elementary interactions of elements in the system are replaced by their integral effect, represented by the delayed switching of an element's state.The present paper is the first of two on the BDE approach to modeling seismicity. Its major results are the following: (i) A model that implements the approach. (ii) Simulating three basic types of seismic regime. (iii) A study of regime switching in a parameter space of the loading and healing rates. The second paper focuses on the earthquake prediction problem.     

THE LATERAL INHOMOGENEITY IN YUNNAN PROVINCE, CHINA

Images of the velocity cross--section at 10 different depths in Yunnan Province have been suc-cessfully reconstructed, using the principle and method of seismic tomography (ST). These velocitycoss-sections are consistent with the results of six velocity profiles of deep seismic sounding. The reconstruction method of ST used in this paper has two advantages: (i) The velocity modeli determined by spe cifying node--velocities of hexahedron and linear interpolation through knownbasic function. A velocity field with lateral continuous velocity value and vertical discontinuitiesis established. This model is obviously better than the block model of constant velocity. The verticaldiscontinuities allow the model to simulate velocity discontinuities in the crust and upper mantle. (ii)The velocity and hypocenter parameters are separated by introducing an orthogonal projection oper-ator. Sequential orthogonal triangularization and modified singular decomposition are adopted.These measures reduce the RAM requirement