A Blast Shock Isolation System with MRFD and Its Semi-Active Control Analysis

To effectively reduce the damage to people and devices in civil defense engineering subjected to blast shock, a blast shock isolation system with magnetorheological fluid dampers （MRFD） is proposed. MRFD can provide continuously adjustable Coulomb friction and has many advantages for semi-active control. Numerical simulation of this isolation system is finished using Matlab simulink toolbox. General semi-active control algorithms are consided based on instantaneous optimal active control algorithm. And the results indicate that the shock isolation system can work efficiently, decreasing about 93% of the peak acceleration of the isolation floor.     

Experimental Studies on High-Frequency Performance of the Inverse Control Magneto-Rheological Damper

Severe vibration of underground structures may be induced under blast loads. According to the characteristics of the explosion-induced ground shock wave, a new-type damper, inverse control magneto-rheological(MR) damper was designed to control the vibration. The high-frequency performance test of the MR damper was carried out on the small shaking table. It is shown that the performance can be modeled by use of the modified Bouc-Wen model, and the parameters of the model keep stable in the ranqe of 15-50 Hz.     

隔震技术在建筑结构中的应用和展望

从隔震和消能减震的角度,对目前土木工程领域结构控制技术进行了综合评述,首先对国内外现有的隔震技术进行了分类探讨;其次根据阻尼器的工作原理,对其进行了分别阐述;最后从我国实际情况出发,对今后隔震技术的研究、应用中需重点解决的问题提出了若干建议。     

双边轮式斜拉桥悬索检测机器人设计与分析(英文)

为了检测斜拉桥圆柱形悬索内部钢丝情况,设计了一种新型的双边轮式悬索爬升机器人,简述了其机械结构及运动方式,建立了爬升模型,分析了其机构的静态特性,并以直径为139 mm的悬索为例给出了相关设计参数.为使机构在电路系统故障时能安全回收,提出了一种基于反电动势理论的安全节能回收方法,应用曲柄滑块驱动气缸设计了气体阻尼机构,以消耗机构下降时因重力作用产生的多余动能,并建立了机构数学模型来仿真下降速度.试验结果表明,所设计的机器人能携带3.5 kg重物沿直径为65～205 mm的悬索平稳运行,满足了悬索检测的实用要求.     

Wind-induced vibration control of long-span power transmission towers

We investigated wind-induced vibration control of long-span power transmission towers based on a case study of the Jingdongnan-Nanyang-Jingmen 1 000 kV transmission line project in P. R. China. The height of the cup tower is 181 m with a ground elevation of 47 m, which makes it a super flexible and wind-sensitive structure. Therefore, we should analyze the wind- resistant capacity of the system. We simulated applicable transverse fluctuating wind velocity field, developed a lead-rubber damper （LRD） for controlling wind-induced vibration of long-span transmission towers, deduced LRD calculation model parameter, and researched the best layout scheme and installation method of LRD. To calculate the wind-induced response of tower-line coupling system in seven layout schemes, we used the time history analysis method, and obtained the efficiencies of wind-induced vibration control. LRD deformation research proved that the damp of all LRDs was efficient under the designed wind velocity when they were laid along the edge of tower heads. We studied the controlling efficiency resulting fTom only applying stiffness to the tower polos where the dampers used to be laid under the designed wind velocity. The results show that the controlling efficiency was not ideal when the stiffness is increased on the poles only. Therefore, LRD should conlxibute to both the stiffness and damp of a structure to effectively reduce the dynamic response of a tower-line coupling system under strong winds. We also discussed the controlling efficiency of LRD under static winds. The results show that there was little difference between displacements derived by the finite clement time history method and those obtained by static wind method conducted by a design institute. This means the simulation on space relevant wind velocity field was accurate and reasonable.     

Linking mathematics with engineering applications at an early stage – implementation,experimental set-up and evaluation of a pilot project

Too difficult, too abstract, too theoretical – many first-year engineering students complain about their mathematics courses. The project MathePraxis aims to resolve this disaffection. It links mathematical methods as they are taught in the first semesters with practical problems from engineering applications – and thereby shall give first-year engineering students a vivid and convincing impression of where they will need mathematics in their later working life. But since real applications usually require more than basic mathematics and first-year engineering students typically are not experienced with construction, mensuration and the use of engineering software, such an approach is hard to realise. In this article, we show that it is possible. We report on the implementation of MathePraxis at Ruhr-Universität Bochum. We describe the set-up and the implementation of a course on designing a mass damper which combines basic mathematical techniques with an impressive experiment. In an accompanying evaluation, we have examined the students' motivation relating to mathematics. This opens up new perspectives how to address the need for a more practically oriented mathematical education in engineering sciences.     

压路机变阻尼减振器的结构设计及仿真分析

针对振动压路机采用的橡胶减振装置存在阻尼不可调的问题,文章利用磁流变液具有快速相变和易于控制的特征,并结合压路机结构特性设计一种由磁流变和橡胶耦合而成的变阻尼减振器,通过力学计算与有限元仿真,对减振器结构设计进行校核与优化。仿真结果发现:经过结构优化的变阻尼减振器提高了控制磁场的利用率,从而提高磁流变橡胶耦合减振器的性能与品质。     

磁流变阻尼器的应用

磁流变流体与电流变流体一起被称为新兴的智能软物质，它具有液一固两相转换的可逆性、连续可控性和响应快速等高技术特征，在液压、振动制动、驱动密封等的主动和自适应控制中具有广阔的应用前景．本讨论了磁流变液的组成、性质，比较了磁流变液与电流变液的不同性质，介绍了磁流变阻尼器的工作模式及其应用．     

图书馆计算机网络机房防朗涌措施探讨

电路中的浪涌已是图书馆计算机网络机房重大安全问题.IT设备防浪涌保护不单纯是防雷击.要综合考虑雷击浪涌、电力线路本身浪涌、感应浪涌和图书馆内部设备产生的浪涌.共用接地系统与等电位联结、屏蔽、阻塞沿电源线或数据信号线引入过电压的四级防浪涌保护.是图书馆计算机网络机房防朗涌最佳措施.     

Numerical analysis on aeolian vibration of transmission lines with Stockbridge dampers

We used computational fluid dynamics （CFD） and mode superposition method instead of the energy balance method to compute transmission line aeolian vibrations induced by the Karman vortex. Firstly, we obtained the wind power inputs using CFD theory. The result is effective for aeolian vibration analyses compared with the power which were measured in wind tunnel tests. Then a new aeolian excitation was derived using the wind power equivalent principle, and the aeolian vibration distribution along transmission lines and the wind power input obtained by CFD can be account. Secondly, we formulated the motion equation of a conductor-damper system and derived a semi-analytial solution using the mode superposition method. The Stockbridge-type dampers attached were simplified to the forces transmitted by the clamps. Finally, the semi-analytical solution can be solved by iterative methods. Taking a 1 000 kV Ultra High Voltage transmission line as an example, we analyzed the line with and without dampers by the semi-analytical solution. Compared with the results which were computed by the energy balance method, the semi-analytical solution is precise enogh for aeolian vibration analyses. Besides, we also analyzed the influence of damper position and quantity.