一种新型的工程岩体探测震源──超磁致伸缩声波发射器

针对工程岩体质量快速精细检测中极为关键的震源问题，提出并采用新型的超磁致伸缩材料，研制成一种特殊的工程岩体探测大功率声波震源系统，并成功地应用于工程岩体的探测之中。文章系统地介绍了超磁致伸缩材料的特性及其声波发射器的设计制作思路以及应用情况，并给出了实例。这种新型的震源具有小体积、大功率、高频率、短余振等优点，在工程岩体检测中有着其它现有各种震源不可替代的作用，是一种十分理想的探测震源。该震源系统除直接应用于工程岩体的地面检测之外，还有着十分广阔的应用前景。     

在地震与爆炸以及冲击载荷作用下分层弹性地基场地土的竖向动力反应分析

对场地上按分层弹性地基土建立了合理的力学模型，通过动力分析，给出了分层弹性地基场地土竖向自振特性及在竖向地震与爆炸以及冲击载荷作用下强迫反应的解析解，文中的解析公式为分层弹性地基场地土的竖向动力反应分析提供了一种新的解析方法．     

振动放顶煤技术机理研究

详细介绍了振动放顶煤技术的原理和机理。通过实验室试验揭示了在重力自然放煤方式下,当顶煤块度达到放煤口宽度的1/3左右时,块裂顶煤在放落过程中极易形成铰接拱,而使后续顶煤难以放落。验证了振动放顶煤技术原理及其机构的可行性,证明了采用振动放顶煤技术可有效地提高顶煤采出率和降低混矸率。     

结构振动的模糊建模与模糊控制规则提取

模糊振动控制中存在的模糊控制规则的建立大都依赖于主观经验的现状。对此本文提出了一种通过对结构振动模糊建模来产生控制规则的方法。首先，通过对系统运动状态变量的模糊化，建立结构振动的模糊关系模型；其次通过对结构振动的模糊关系模型的分析，提取出模糊控制规则；最后，通过一个单自由度体系的数值仿真方法进行了验证。     

A new method for non‐stationary random critical excitation

Since earthquake ground motions are very uncertain even with the present knowledge, it is desirable to develop a robust structural design method taking into account these uncertainties. Critical excitation approaches are promising and a new non‐stationary random critical excitation method is proposed. In contrast to the conventional critical excitation methods, a stochastic response index is treated as the objective function to be maximized. The power (area of power spectral density (PSD) function) and the intensity (magnitude of PSD function) are fixed and the critical excitation is found under these restrictions. It is shown that the original idea for stationary random inputs can be utilized effectively in the procedure for finding a critical excitation for non‐stationary random inputs. The key for finding the new non‐stationary random critical excitation is the exchange of the order of the double maximization procedures with respect to time and to the power spectral density function. Copyright © 2001 John Wiley & Sons, Ltd.     

砖石古塔的地震“修复”及动力学特征初探

汇集了 4例震裂古塔震而复合的有关历史资料。分析认为可探索用人工激震方法对开裂古塔进行修复。从震害资料看出 ,砖石古塔在地震烈度 度以上时将出现破坏。研究了砖石古塔的结构特性 ,提出了对古塔自振周期的计算公式。指出这些研究对古塔的修复、加固及抗震性能评价 ,无疑是有益的     

Determination of soil impedance functions from vibration-test response of a circular foundation

The paper presents the results of the determination from vibration tests of impedance functions for a concrete basemat of a one-quarter scale model of a nuclear power-plant containment building. The tests were designed to excite all rigid-body modes of the foundation. In addition to the impedance functions for all the rigid-body degrees of freedom, natural frequencies and damping for the fundamental modes were estimated. Comparison of the test-determined modal characteristics with corresponding analytical ones based on the Lysmer analog shows that though the latter gives natural-frequency estimates of the right order of magnitude, it does not give acceptable estimates of the damping coefficient. Analytical impedance functions based on a model of a rigid-plate on an elastic half-space were found to have the sam trend as the test-determined ones at lower frequencies, but not at higher frequencies. The utility of test data for verification of analysis is discussed.     

关于在动力机器基础现场模型试验中用拉伸回弹法求地基刚度的探讨

在动力机器基础测试中,拉伸回弹法是一种简易实用的瞬态激振方法;它比常用的球击法具有激振能量大,信号接收效果佳等优点。但运用该法如何求地基刚度的计算却不多见,故本文简要地列出我们推导的算式,以供参考与探讨。     

蒙脱石晶体结构和水结构的矿物物理特征

本文利用矿物物理研究方法对我国内蒙、浙江、甘肃等地的钙基、钠基、镁基蒙脱石的物质成分、晶体结构和层间OH,H_2O的排布结构进行了研究,并获得下列结论: 1.由X衍射和拉曼分子光谱分析深入研究了蒙脱石阳离子配位体结构特征,提出其空间群为C_2/m型。 2.建立了蒙脱石水结构模式,有3种主要类型:①层间大阳离子附近的束缚态水分子;②层间无大阳离子位置上的非束缚态水分子;③颗粒表面依靠氢键相连的水分子集合体。 3.利用群理论,提出了蒙脱石OH~-的振动模式,由振动分析指出蒙脱石中OH~-具有12个振动模式。     

Ambient vibration studies for system identification of tall buildings

The performance of a building under wind and seismic loads depends on stiffness and mass distribution, and may be estimated using finite element codes. Experience has, however, shown that such finite element models often fail to predict accurately the fundamental natural frequencies. Usually the frequencies will be underestimated, that is the building will turn out to be stiffer than anticipated, meaning the design would usually be conservative. On the other hand, effects like torsional eccentricity and foundation compliance may not be correctly modelled, which could be less desirable. A full understanding of linear performance under lateral loads can be obtained through experimental evaluation of the vibration modes. Traditionally only a limited range of modal analysis procedures and software has been applied to civil applications and the ‘special case’ where no input forces can be measured has been the usual situation for large civil structures. Recent developments in system identification, which is the set of procedures to build mathematical models of the dynamic structural systems based on measured data, have added significantly to the potential of ambient vibration or ‘output only’ testing. The aim of the research reported here has been to apply and evaluate the procedures on typical buildings. The procedures are briefly explained and two experimental programmes are then described; a long‐term tremor monitoring exercise on a 280m office tower and an ambient vibration survey of a smaller office block. The different forms of response data are examined to study the performance of the analysis procedures and expose benefits and limitations in their use. There is a growing interest in output‐only modal analysis procedures in civil engineering. The experience reported in this paper has shown that quick and reliable estimation of mode shapes and frequencies can be obtained, even with small amounts of data. Judgement of modal participation and damping ratios requires more detailed study yet the results are at least as convincing as existing and relatively limited frequency domain methods. Copyright © 2002 John Wiley & Sons, Ltd.