结构异形面平动在砂土中产生的土压力作用模式

为探究结构异形面对土‒结构相互作用的影响,通过室内模型试验,研究了不同形状结构面在平动模式下与砂土的相互作用规律,考虑外凸形、平板形和内凹形3种典型结构面,测量了结构水平移动时表面不同位置的接触应力和土体位移场变化情况。试验结果表明,结构形状对土压力最大值、土压力分布以及土体地表影响范围有显著影响。在相同的相对位移下,外凸形的土压力最大值最大,平板形次之,内凹形最小;土压力分布方面,外凸形和内凹形结构的土压力分布为梯形与“斜椭圆”叠加,平板形土压力分布为梯形与正弦函数叠加;外凸形的地表影响宽度最大,平板形次之,内凹形最小。

基础平动结构随机地震响应的解析解

对单自由度基础平动结构随机地震响应问题进行了系统研究。针对结构运动方程为非经典阻尼、非对称质量和非对称刚度的情况,用复模态法解耦,获得了结构地震响应的解析解。该方法可推广到非平稳随机地震响应分析,也可用于基础隔震、带TMD减震和加层减震等结构的随机地震响应分析与优化设计。

Simulation and Analysis of Land System Structure Changes in Huang-Huai-Hai Plain Area

The dynamic changes of land system in Huang - Huai - Hai Plain between 1988 and 2000 were researched in this paper. Spatial dominance econometric model was estabilished on 1 km cell to quantificafionally analyze the driving-force for the dynamic change mechanism of land system, such as natural, social and economic factors. The future dynamic changes of land system in Huang - Huai - Hai Plain on each 1 km cell during 2000 to 2020 were stimulated by combining the dynamic changes of land system on each 1 km cell with different situations. The research indicated that the dynamic changes of land system structure changed mainly from the cultivated areas to building areas and industrial areas, and forest areas increased during this period. Although the revolutions of land system structure were different during 2000 to 2020 with the different referrence standard, ecological protection and economic development, the primary dynamic changes of land system structure were that the increase of building land areas with the decline cuhivaled land areas and the increase of woodlands.

A Into-Plane Rotating Micromirror Actuated by a Hybrid Electrostatic Driving Structure

A novel into-plane rotating rnicromirror actuated by a hybrid electrostatic driving structure is presented. The hybrid driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process. As demonstrated by experiment, the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90°rotation induced by the pull-in effect. The continuous rotating range of the micromirror is increased to about 46° at an increased yielding voltage. The measured yielding voltages of the mirrors with torsional springs of 1 and 0.5μm in thickness are 390 - 410V and 140 - 160V, respectively. The optical insertion loss has also been measured to be --1.98dB when the mirror serves as an optical switch.

Kineto-static analysis of a novel high-speed parallel manipulator with rigid-flexible coupled links

A novel high-speed parallel kinematic machine （PKM） named Delta-S parallel manipulator is proposed, which consists of a fixed base connected to a moving platform through three limbs with identical topology. Each limb is composed of one driving ann and one follower arm, herein, the latter includes two strings and one middle rod, all located in a same plane. Compared with similar manipulators with uniform parameters, the novel and unique topology as well as the addition of two strings of Delta-S manipulator can remove the clearance of the spherical joints, reduce the inertial load of components further, improve the positioning accuracy and dynamic performance, and so on. In order to formulate the kineto-static model of Delta-S manipulator, the kineto-static analyses and models of the driving arm, the generalized follower and the moving platform can be carried out by the D＇ALEMBERT principle. For the sake of obtaining the force analytic results of strings, the deformation compatibility condition of strings and the middle rod are determined. Furthermore, in virtue of the assumption of small deformation and the linear superposition principle, the minimal pre-tightening force of the strings is calculated. The main results include that the loads of the strings and the middle rod must be larger than ＂zero＂ and the pre-tightening force over the workspace must be larger than the minimal pre-tightening force at any time within the workspace, which lay the foundation for the dynamic analysis and the prototype manufacture of the Delta-S manipulator.

Transient response of piles-bridge under horizontal excitation

Moving ships and other objects drifting on water often impact a bridge' s pile foundations. The mechanical model of the piles-bridge structure under horizontal forcing was established, and a time-domain approach based on Finite-difference Method was developed for analyzing the dynamic response of the piles-bridge structure. For a single pile, good agreement between two computed results validated the present approach.The slenderness ratio of the pile, the pile-soil stiffness ratio and the type of the structure influence the dynamic response of the piles-bridge structure. The computed results showed that the stiffness of the structure determines the dynamic response of the piles-bridge structure under horizontal forcing.

Simultaneous investigation of blast induced ground vibration and airblast effects on safety level of structures and human in surface blasting

The significance of studying, monitoring and predicting blast induced vibration and noise level in mining and civil activities is justified in the capability of imposing damages, sense of uncertainty due to negative psychological impacts on involved personnel and also judicial complaints of local inhabitants in the nearby area. This paper presents achieved results during an investigation carried out at Sungun Copper Mine, lran. Besides, the research also studied the significance of blast induced ground vibration and air- blast on safety aspects of nearby structures, potential risks, frequency analysis, and human response. According to the United States Bureau of Mines （USBM） standard, the attenuation equations were devel- oped using field records. A general frequency analysis and risk evaluation revealed that： 94% of generated frequencies are less than 14 Hz which is within the natural frequency of structures that increases risk of damage. At the end, studies of human response showed destructive effects of the phenomena by ranging between 2.54 and 25.40 mm/s for ground vibrations and by the average value of 110 dB for noise levels which could increase sense of uncertainty among involved employees.

Impact of Passive Heave Compensator on Offshore Lifting

Splash zone crossing of the structures with large horizontal surface （e.g. manifolds） and the structures having large weight variation in water and air （e.g. suction anchors） is a critical marine operation. This is due to the large slamming forces and added mass of the structure, which results in high dynamic loads on the crane. The solution to this could be attaching a PHC （Passive Heave Compensator） between the crane hook and the payload. This paper analyzes the deployment of a subsea manifold with and without PHC unit in North Sea at a water depth of approximately 370 m. A detailed dynamic analysis is done for a seastate of 3 m significant wave height （Hs） over a range of zero up-crossing period （Tz） varying from 3s to 13 s. For better understanding of the result analysis has been done in two stages. The first stage covers the lowering of manifold through the splash zone while second stage covers the seabed landing of the manifold. Based on the results of the analyses it is concluded that PHC tends to reduce the dynamic peak load on the crane. Besides this, it also mitigates the risk of slack wire situations during splash zone crossing of the payload. Furthermore, reduction in both landing velocity and crane tip velocity is also achieved by using a well-designed PHC unit.

A Simple Structure Model for Enzyme Production by Phanerochaete chrysosporium

In order to understand the behavior of ligninolytic enzyme production by white rot fungi Phanerochaete chrysosporium, study on time courses and a mathematical model for the production of lignin peroxidase (LiP) and manganese peroxidase (MnP) of the fungi was undertaken. Based on the Monod-Jacob operon model, the ligninolytic enzyme would be synthesized in the absence of a related repressor. The repressor is assumed to be active in the presence of ammonia nitrogen, and as combined as co-repressor, it causes the inhibition of enzyme synthesis. The model can explain the mechanism of extracellular ligninolytic enzyme production by white rot fungi. The results,as predicted by the model, correspond closely to those observed in experimental studies. In addition, some light is also shed on unmeasured variables, such as the concentrations of repressor and mRNA that are related to the enzyme synthesis.

Flow Behaviors of Non-spherical Granules in Rectangular Hopper

Flow behaviors of four kinds of granular particles(i.e. sphere,ellipsoid,hexahedron and binary mixture of sphere and hexahedron) in rectangular hoppers were experimentally studied. The effects of granular shape and hopper structure on flow pattern,discharge fraction,mean particle residence time and tracer concentration distribu-tion were tested based on the visual observation and particle tracer technique. The results show that particle shape affects significantly the flow pattern. The flow patterns of sphere,ellipsoid and binary mixture are all parabolic shape,and the flow pattern shows no significant difference with the change of wedge angle. The flowing zone be-comes more sharp-angled with the increasing outlet size. The flow pattern of hexahedron is featured with straight lines. The discharge rates are in increasing order from hexahedron,sphere,binary mixture to ellipsoid. The dis-charge rate also increases with the wedge angle and outlet size. The mean particle residence time becomes shorter when the outlet size increases. The difference of mean particle residence time between the maximum and minimum values decreases as the wedge angle increases. The residence time of hexahedron is the shortest. The tracer concen-tration distribution of hexahedron at any height is more uniform than that of binary mixture. The tracer concentra-tion of sphere in the middle is lower than that near the wall,and the contrary tendency is found for ellipsoid particles.

Electromagnetic drive system of robotic fish

With the aim to apply the electric fish into practice to assist coal mine water disaster life detection and rescue work, based on the analysis on swing propulsion movements of tail fin, this paper integrates the electromagnet technology with tail fin drive system by analyzing how the fish swims with tail fin under the law of progression. The principle, structure, and drive signals of tail fin electromagnetic drive are researched, the enforced situation of fish under eIectromagnetic driving modes are analyzed, and the experimental plat-form of tail fin electromagnetic drive is established. The best distance between electro- magnet and armature, which can realize the swing of tail fin, was researched in the experiment under water. The robotic fish structure parameters of tail fin electromagnetic drive was finalized by theoretical analysis and experimental measurement.

DYNAMIC FINITE LAYER-ELEMENT ANALYSIS OF SOIL-STRUOTURE INTERACTION FOR NEW-TYPE OFFSHORE PLATFORM

In this paper, a new method called dynamic finite layer--element method (DFLEM) is used to analyse the soil--structure interaction of new type offshore platforms. Some valuable results have been obtained. The results show that the DFLEM is a new effective method to analyse dynamic soil--structure interaction and can be applied widely in practice.

Advanced Self-Localization and Navigation for Mobile Robots in Extraterrestrial Environments

Self-localization is one of the most important aspects for using mobile robots in unstructured environments. In this paper, the authors introduce a new approach for a self-localization and navigation unit for mobile platforms in extraterrestrial environments, based on the authors＂ successful results in self-localization of forestry machines on earth. The presented approach is developed from a highly modular concept, which allows a simple but efficient adaption to specific applications by just substituting some scenario dependent components. In this paper, the authors will explain the general concept and the terrestrial implementation so far. On this basis, the authors will demonstrate and discuss the necessary adaptions to the general concept in order to handle the different conditions on extraterrestrial surfaces.

A Wind Tunnel Two-Dimensional Parametric Investigation of Biplane Configurations

This paper presents an experimental and systematic investigation about how geometric parameters on a biplane configuration have an influence on aerodynamic parameters. This experimental investigation has been developed in a two-dimensional approach. Theoretical studies about biplanes configurations have been developed in the past, but there is not enough information about experimental wind tunnel data at low Reynolds number. This two-dimensional study is a first step to further tridimensional investigations about the box wing configuration. The main objective of the study is to find the relationships between the geometrical parameters which present the best aerodynamic behavior： the highest lift, the lowest drag and the lowest slope of the pitching moment. A tridimensional wing-box model will be designed following the pattern of the two dimensional study conclusions. It will respond to the geometrical relationships that have been considered to show the better aerodynamic behavior. This box-wing model will be studied in the aim of comparing the advantages and disadvantages between this biplane configuration and the plane configuration, looking for implementing the box-wing in the UAV＇s field. Although the box wing configuration has been used in a small number of existing UAV, prestigious researchers have found it as a field of high aerodynamic and structural potential.

Coupling simulation of fluid structure interaction in the stirred vessel with a pitched blade turbine

The interaction between fluid and a down-pumping pitched blade turbine fixed with a flexible shaft in the stirred vessel, as a typical fluid structure interaction phenomenon, was simulated by coupling the Computational Fluid Dynamics and Computational Structural Dynamics. Based on the verification of the simulated impeller torque and dimensionless shaft bending moment with experimental result, the dimensionless shaft bending moment and various loads acting on impeller(including lateral force, axial force and bending moment) were discussed in detail. By separating and extracting the fluid and structural components from those loads, the results show that the shaft bending moment mainly results from the lateral force on impeller although the axial force on impeller is much larger. The impeller mass imbalance increases the shaft bending moment and the lateral force on impeller, but has little influence on the axial force and bending moment acting on impeller. The dominant frequencies of impeller forces are macro-frequency, speed frequency and blade passing frequency, and are associated with the impeller mass imbalance.

International Strategy Studies Teaching of High School English Adaptation

With the development of the internationalization of education is increasingly evident in the internationalization of education background, high school English teaching should take the initiative to adapt to developments in the new situation. This article on how to improve their own quality, improve teaching effectiveness, students of English communication ability, so that students in the current international context can adapt to the development of education research are discussed. Under international background education driven, high school English teaching will face new challenges, for high school English teachers, should constantly update their knowledge structure, knowledge reserves, in the process of globalization, who can grasp the elements of various resources flow law, who is likely to benefit fxom the flow of resources, and upgrade themselves. Only in the tide of globalization continue to challenge themselves, subjected to erosion and baptism, education level of high school to a new level is possible. Current international education is not only abroad, but multicultural harmony and tolerance, in order to comply with the objective needs of the times, constantly updated teaching ideas, positive reform and innovation to achieve the level of English international high school continues to increase.

Nonlinear dynamic buckling of stiffened plates under in-plane impact load

This paper presents a simple solution of the dynamic buckling of stiffened plates under in-plane impact loading. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stresses of stiffeners and in-plane displacement are neglected. Appling the Hamilton's principle, the motion equations of stiffened plates are obtained. The deflection of the plate is taken as Fourier series, and using Galerkin method the discrete equations can be deduced, which can be solved easily by Runge-Kutta method. The dynamic buckling loads of the stiffened plates are obtained form Budiansky-Roth criterion.

Research on Enterprise Mobile Office Platform based on Cloud Computing

This paper systematically analyzes the structure and function of mobile office system in cloud platform, puts forward the method how to blend the advantages of cloud computing to organically integrate mobile office scene. Firstly, this paper introduces the key technology of mobile OA platform based on cloud computing; secondly, this paper proposes the ideas of cloud computing middleware combination with original system, and on this basis, forming a mobile office architecture model based on cloud computing, gives the mobile office platform architecture scheme, combined with the actual development problems in some model specifications and solutions to build mobile office system based on cloud computing..

In-place structural strength and fatigue analysis for floating platform topsides

This paper presents some insights on the state-of-the-art practice that has been utilized recently in the inplace structural strength and fatigue analysis for topsides on deepwater floating platforms such as tension leg plat-form (TLP) and semi-submersibles. Emphases are put on analysis software,geometric and mass modeling,hydro-dynamic loading and its mapping,and analysis procedures. In addition,for the in-place analysis using structure analysis computer system (SACS),the procedure of Visual Basic for Application (VBA) is developed to map AQWA-LINE hydrodynamic loading to the SACS integrated hull/topsides model;for the in-place analysis using structure engineering system analysis model (SESAM),many computer aided applications are made to aid the post-processing. These applications have been used in structural analyses for a few TLP and semi-submersible plat-form topsides,and are briefly introduced in this paper.

Use of Crescent Shaped Braces for Controlled Seismic Design of Ductile Structures

It is known that the seismic response of a structural system is highly influenced, in addition to the earthquake input, by the dynamic characteristics of the system itself. This paper presents an approach for the identification of the characteristics of the structural system resisting to horizontal loads which enables to satisfy given seismic performance objectives. This is achieved by considering a total conceptual separation between the structural systems resisting to vertical and horizontal loads. The proposed approach is first briefly developed in general within a Performance-Based Seismic Design （PBSD） framework and then fully applied to the case study of a five-storey steel building structure. It is composed of three basic steps： （1） identification of the fundamental characteristics which should be possessed by the horizontal resisting system to satisfy a multiplicity of performance objectives, （2） development of a peculiar horizontal resisting system composed of ＂crescent shaped braces＂ which are specifically calibrated to satisfy given performance objectives, （3） verification, by means of appropriate time-history analyses, of the seismic performances achieved. In detail, the horizontal resisting system is calibrated to satisfy a multiplicity of performance objectives through the identification of an ＂objectives curve＂, in the Force-Displacement diagram, of the mechanical characteristics of the structure. The calibration is obtained by methods/tools borrowed either from Direct Displacement-Based Design （DDBD） or Force-Based Design （FBD）, depending on the specific performance objective to be imposed. The applicative example has been carried out with reference to three performance objectives and has led to the identification of a horizontal resisting system composed of special bracing elements capable of realizing a sort of properly-calibrated seismic isolation called crescent-shaped braces. The results obtained through non-linear dynamic analyses have shown that the proposed approach leads to the congruity between the imposed and the achieved seismic performances.