拆除爆破中裸露钢筋骨架的失稳模型

拆除爆破中,框架承重立柱裸露铜筋骨架的失稳,并非单根主筋压杆失稳的简单的数学来迭加,其实质是一小型刚架的有侧向弹性约束的失稳。依此推导了具有一般性的裸露钢筋骨架的失稳临界荷载计算公式。     

控制爆破拆除双曲拱桥

根据双曲拱桥的结构特点，采用单侧失稳爆破方案，仅用７５０ｇ炸药爆破，就达到使整个桥面全部塌落的爆破目的。然后利用钻孔法爆破拆除桥墩，桥台，取得了快速，经济，安全的理想效果。     

钢筋混凝土单立柱定向爆破拆除

通过分析钢筋的失稳条件,设计装药结构及研究钢筋混凝土单立柱的宏观运动,能精确的控制钢筋混凝土的单立柱的倒塌方向,并能确保一排钢筋混凝土立柱在排面的垂直方向上的定向倒塌。     

应用有限元和DDA模拟框架结构建筑物拆除爆破

针对建筑物拆除爆破设计中失稳和倒塌范围，提出了采用有限元和DDA进行拆除爆破的数值模拟方法，并以框架结构建筑物为例，进行了实例研究，得到了一系列有实用价值的研究成果。     

双曲线冷却塔爆破拆除切口参数的探讨

结合茂名电厂双曲线冷却塔爆破拆除工程实例,分析总结了高大冷却塔的结构特点和失稳倾倒机理.在此基础上,采用力学原理分析了爆破切口圆心角和高度等主要参数的计算方法,对类似工程有理论和实践指导意义.     

桥礅柱定向倒塌拆除爆破后坐分析

根据建筑物拆除爆破失稳原理，对桥礅柱定向倒塌控制爆破拆除试爆时产生后坐进行力学分析，得出试爆产生后坐的主要原因是保留支撑截面瞬间强度不够，调整主爆相关参数，使主爆达到预期效果。     

百米钢筋混凝土烟囱定向爆破拆除

介绍了电厂100m高钢筋混凝土烟囱的无后坐定向爆破,取相对偏小的爆破切口对应圆心角,提高支撑强度,防止后坐;同时预先割断爆破时支撑部位的受拉钢筋,减小烟囱倾倒的抵抗力矩,确保烟囱的失稳倾倒.     

井塔滑模施工质量控制

井塔作为矿区主要的提升建筑物,井塔滑模施工是滑模系统组装、钢筋、混凝土、模板滑升工序交叉在一起的施工工艺,4个环节紧密联系和结合,一个环节出现问题滞后,其他3个环节也会受到联锁影响。下面将结合金川三矿区滑模施工,针对滑模钢筋、混凝土和滑模体系的质量问题成因,提出了具体的施工控制措施,保证了井塔滑模施工质量。金川三矿区东部贫矿开采工程主井井塔工程,建筑面积为3380m~2,该工程为钢筋砼框架剪力墙结构,井塔轴线尺寸为16.0m×20m,建筑总高度90m,钢筋混凝土剪力墙厚350mm。总滑模高度73m。     

复杂环境危房的爆破拆除

介绍了两栋复杂环境危房的爆破拆除，分别为排架结构加框架结构的混合结构和砖混结构的五层楼。根据周围环境和待爆建筑物的结构特点，简要分析了排架结构失稳下坠时的受力状况，排架结构加框架结构的混合结构采取纵向逐排爆破倒塌的方案，较好地控制了倒塌方向和范围。     

钢筋混凝土排架的控爆拆除

本文研究了爆破拆除钢筋混凝土建筑物时建筑结构的失稳条件,对钢筋混凝土排架的控制爆破拆除进行了设计计算,并分析了拆除爆破效果和拆除爆破对钢筋混凝土基础的影响。     

Estimating the stability of a complicated system on repeated loading

An approach is proposed to determining the stability of a complicated engineering system under conditions of unregulated effects of destabilizing factors. Forms are obtained for the probability of retaining viability, which allow one to incorporate the repeated action of the destabilizing factors no matter what their differing physical natures. Translated from Izmeritel’naya Tekhnika, No. 2, pp. 17–19, February, 2009.     

爆破拆除烟囱倒塌过程中风效应影响研究

在烟囱爆破拆除倒塌过程中,不同形式的风可使烟囱产生顺风向效应及横风向效应。横风向效应又包括横风向旋涡脱落及共振效应、横风向空气动力失稳。烟囱在风的长期作用下会发生失稳倾斜。本文揭示了爆破拆除过程中烟囱由于风振影响而发生倾斜、失稳的机理,分析了不同风向的三类风效应对爆破拆除时烟囱倒塌方向发生偏移的影响。根据分析计算结果可得,纵向风振影响最为显著,静力风效应影响相对较小,横向风振产生影响随机性较强。同时作者得出了爆破拆除烟囱时考虑风效应影响需采取的相应技术手段和措施。     

On the stability of a hot rotating layer of micropolar fluid

The convective stability of a horizontal layer of incompressible micropolar fluid heated from below and rotating about a vertical axis has been investigated on the basis of linear theory, using normal mode analysis. The boundaries are assumed to be free. After introducing the corrections to the basic equations considered by Sastry and Rao [1], it has been found that the rotation has a destabilizing effect which contradicts the earlier assertion presented in [1].Moreover, microinertia, which does not affect the stability of a hot horizontal layer of incompressible micropolar fluid in the absence of rotation [2], is found to have destabilizing effect.     

Design of Smart Sensors Based on the Introduction of Minimal Structural Redundancy

Measurement Techniques - Problems related to the use of measurement systems and the variation of the parameters of measurement systems under the effect of different types of destabilizing factors,...     

Method for Concurrent Identification of a Linear Dynamic Measurement System Based on Preliminary Nonlinear Transformation of the Input Signal

Measurement Techniques - We consider the problem of the concurrent identification of a linear dynamic measuring system with an unknown input signal under the influence of various destabilizing...     

Eddy Current Detection of Retained Austenite in Ni-Hard4 Cast Iron

In this article, the nondestructive eddy current (EC) method was used for microstructural evaluation of Ni-hard4 cast iron (NiHCI). Different destabilizing heat treatments were used to produce different microstructures and hardness. The microstructural analysis and hardness measurement were done for conventional characterization of the reference blocks. Then, the EC techniques were applied to evaluate the hardness and microstructural changes by the detection of EC parameters at different frequencies. Metallurgical investigations showed that increasing the destabilizing soaking time and temperature decreases the amount of retained austenite in NiHCIs. The nondestructive evaluation method (NDT) revealed that it can be good correlated between retained austenite amount and hardness with EC parameters. This shows that the EC technique can detect NiHCIs products according to the metallurgical characterization with good accuracy.     

Electromagnetic screening of the elements of a high-voltage vacuum divider

The efficiency of constructional-technological measures for screening the most vulnerable components of high-voltage vacuum capacitive dividers, which are exposed during use to the destabilizing actions of intense external electromagnetic fields, is estimated.     

Onset of thermal instability in a horizontal layer of fluid with modulated boundary temperatures

Thermal instability in a horizontal layer of fluid, with the boundary temperatures modulated sinusoidally in time, is studied. The amplitude of modulation is assumed small and is used as an expansion parameter. It is shown that an exact solution can be obtained, even when the boundaries are considered to be rigid. When only the lower boundary temperature is modulated, for small values of the Prandtl number modulation is always stabilizing, while for large values it can be stabilizing or destabilizing depending on the modulation frequency. When both boundary temperatures are modulated in phase, modulation is destabilizing for low modulation frequency, but for higher modulation frequency stabilization occurs for low values of the Prandtl number. When the two boundary temperatures are modulated out of phase the modulation always has a stabilizing effect.     

Application of pressure transducers subjected to large vibrations

Conclusions The application of the above system for protecting the means of measurement from appreciably destabilizing effects ensures that the required statistical measurement precision is obtained, trustworthy information about the dynamic processes (in measuring relatively high pressures) which occur over periods exceeding 0.03 sec is provided, and a higher reliability for the normal functioning of a measurement channel is ensured with its possible future utilization for controlling the working objects with a speed of operation exceeding that of existing control systems.In principle the above system for protecting pressure transducers from destabilizing effects can be extended to the measurement of lower pressures and processes with characteristic durations down to 0.01 sec. This entails reducing the pipeline length and preserving at the same time the vibration properties of the system.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 23–25, October, 1969.     

On the stability of double diffusive convection in a porous layer with throughflow

Summary The effect of throughflow on the stability of double diffusive convection in a porous layer is investigated for different types of hydrodynamic boundary conditions. The lower and upper boundaries are assumed to be insulating to temperature and concentration perturbations. The resulting eigenvalue problem is solved by the Galerkin technique. The curvature of the basic temperature as well as solute concentration gradients significantly affects the stability of the system. It is observed that, for a suitable choice of parametric values, Hopf bifurcation occurs always prior to direct bifurcation, and the throughflow alters the nature of bifurcation. In contrast to the single component system, it is found that throughflow is (a) destabilizing even if the lower and upper boundaries are of the same type, and (b) stabilizing as well as destabilizing, irrespective of its direction, when the boundaries are of different types.