Showing papers by "Qiusheng Li published in 2003"
TL;DR: In this paper, a good epitaxial relationship between the Zn core and ZnO shell was observed, and misfit dislocations were observed at the interface, which accommodated the relatively large lattice mismatch.
Abstract: Coaxial Zn/ZnO nanocables and ZnO nanotubes have been fabricated via a thermal reduction route using ZnS powder as the source material. The samples were characterized using X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry. The as-synthesized Zn/ZnO nanocables consisted of a metallic core (Zn) ≈50 nm in diameter and a semiconductor outer shell (ZnO) ≈5 nm in thickness and several micrometers in length. A good epitaxial relationship between the Zn core and ZnO shell was observed, and misfit dislocations were observed at the Zn/ZnO interface, which accommodated the relatively large lattice mismatch. The outer diameter and wall thickness of the ZnO nanotubes are ≈60 and ≈10 nm, respectively. The possible formation mechanisms for the Zn/ZnO nanocables and ZnO nanotubes are discussed.
302 citations
TL;DR: In this paper, a shape memory alloy (SMA) damper was developed for structural control implementation, and eight SMA dampers were installed in a frame structure to verify the effectiveness of the damper devices.
Abstract: A damper device based on shape memory alloy (SMA) wires is developed for structural control implementation. The design procedures of the SMA damper are presented. As a case study, eight such SMA dampers are installed in a frame structure to verify the effectiveness of the damper devices. Experimental results show that vibration decay of the SMA damper controlled frame is much faster than that of the uncontrolled frame. The finite-element method is adopted to conduct the free and forced vibration analysis of the controlled and uncontrolled frame. The experimental and numerical results illustrate that the developed SMA dampers are very effective in reducing structural response and have great potential for use as efficient energy dissipation devices with the advantages of good control of force and no lifetime limits, etc.
123 citations
TL;DR: In this article, the optimum designs of multi-outriggers in tall building structures are presented and discussed through the analysis of structural performance of outrigger-braced frame-core structures.
Abstract: The optimum designs of multi-outriggers in tall building structures are presented and discussed in this paper, through the analysis of structural performance of outrigger-braced frame-core structures. The influences of the locations of outriggers and the variations of structural element stiffness on the base moment in core, top drift and fundamental vibration period of such tall building structures are analysed in detail. A non-linear optimum design procedure for reducing the base moment in the core is presented based on the penalty function method. The computer programs are developed on the basis of the proposed methods for analysing the behaviour and optimum design of multi-outrigger structures. A series of figures presented in this paper can be used for the design purposes of outrigger-braced tall building structures. Copyright © 2003 John Wiley & Sons, Ltd.
91 citations
TL;DR: In this paper, a modified independent modal space control (MIMSC) algorithm is proposed to eliminate the effect of modal control force on the uncontrolled modes, which is more effective than IMSC.
46 citations
TL;DR: In this article, an analytical solution for the four-equation model describing fluid-structure interaction in liquid-filled pipes subjected to impact-induced water hammer is presented, which is in good agreement with experimental measurements and with numerical solutions determined by the method of characteristics.
Abstract: In this paper, an analytical solution for the four-equation model describing fluid-structure interaction in liquid-filled pipes subjected to impact-induced water hammer is presented. The analytical solution is derived for the case of both Poisson coupling and junction coupling. The results obtained from the analytical solution are in good agreement with experimental measurements and with numerical solutions determined by the method of characteristics. Taking advantage of the analytical solution, some features of coupled wave propagation are presented and discussed.
43 citations
TL;DR: In this article, the amplitude-dependent characteristics of damping that were obtained by using the random decrement technique are investigated on the basis of the field measurements, and the full-scale measurements are compared with the wind tunnel results.
Abstract: Central Plaza has a height of approximately 374 m and is 78-storeys tall. It is the tallest structure in Hong Kong and was the highest reinforced-concrete building in the world when it was built several years ago. This paper describes some results obtained from the full-scale measurements of wind effects on Central Plaza. The field data such as wind speed, wind direction and acceleration responses have been measured during the close passage of several typhoons in recent years. Detailed analysis of the field data is conducted to investigate wind effects on the tall building. The full-scale measurements are compared with the wind tunnel results. The amplitude-dependent characteristics of damping that were obtained by using the random decrement technique are investigated on the basis of the field measurements. Copyright © 2003 John Wiley & Sons, Ltd.
36 citations
TL;DR: In this article, an effective method for determining the optimal position of actuators in tall buildings using genetic algorithm is introduced through the formulation of a discrete and non-linear optimization problem.
36 citations
TL;DR: In this article, an analytical approach for determining vibratory characteristics of cracked Timoshenko beams is proposed based on the rotational spring model for describing the local flexibility induced by a crack and the developed fundamental solutions.
Abstract: An analytical approach is proposed for determining vibratory characteristics of cracked Timoshenko beams. Based on the rotational spring model for describing the local flexibility induced by a crack and the developed fundamental solutions, the frequency equation for a Timoshenko beam with any kind of two end supports and an arbitrary number of cracks can be established from a second-order determinant. The decrease in the determinant order can lead to significant savings in the computational time.
35 citations
TL;DR: In this paper, the large deflection equation of a shallow spherical shell under uniformly distributed transverse loads is established with consideration of effects of transverse shear deformation on flexural deformation.
34 citations
TL;DR: In this paper, a new probability distribution function for evaluating the failure probability of concrete components is proposed, and a simplified measurement method for determining the parameters of the governing Weibull distribution, using the three-point bending test, is presented and discussed.
27 citations
TL;DR: In this article, an exact approach for free vibration of an isotropic rectangular plate carrying a line-concentrated mass and with a linetranslational spring support or with an elastic line-spring mass system is presented.
TL;DR: In this article, a model of massless rotational spring is adopted to describe the local flexibility induced by cracks in the column and the exact buckling solutions of one-step non-uniform columns are found.
TL;DR: In this article, a nonlinear dynamic finite element technique is developed to analyze the elastoplastic dynamic response of single-layer reticulated shells under strong earthquake excitation, in which the nonlinear three-dimensional beam elements are employed.
TL;DR: In this paper, a new systematic approach to the shear lag analysis of structures that are subjected to simultaneous bending and axial forces is presented, based on the principle of minimum potential energy.
TL;DR: In this article, the buckling of non-uniform bars with rotational and translational springs subjected to concentrated axial compressive forces is given by the second order differential equation for bending moment M ( x ).
TL;DR: In this article, an analytical approach and exact solutions for the torsional vibration of a multi-step non-uniform rod carrying an arbitrary number of concentrated elements such as rigid disks and with classical or non-classical boundary conditions is presented.
TL;DR: In this paper, an efficient approach to the nonlinear analysis of plate-truss composite steel girders is presented using finite strip elements in transverse direction, where the effect of material nonlinear behavior is considered with inner-force plastic coefficients of cross section.
TL;DR: In this paper, the effects of a vectored trailing edge jet on the leading edge vortex breakdown of a 65° delta wing were studied and the experimental results indicated that the effect of the jet control tends to be weaker with the angle of attack.
Abstract: Flow visualization was used to study the effects of a vectored trailing edge jet on the leading edge vortex breakdown of a 65° delta wing. The experimental results indicated that there is little effect of the jet on the leading edge vortex breakdown when the angle of the vectored jet is less than 10°. With the increase of the vectored angle β, the effect of the jet on the flow becomes stronger, i.e., the jet delays the leading edge vortex breakdown in the direction of the vectored jet, and accelerates breakdown of the other leading edge vortex. Moreover, the effect of the jet control tends to be weaker with the angle of attack.
TL;DR: In this article, the buckling of a one-step bar with the effect of shear deformation is established and its exact solution is obtained, which is then used to derive the eigenvalue equation of a multistage bar.
Abstract: The governing differential equation for buckling of a one-step bar with the effect of shear deformation is established and its exact solution is obtained. Then, the exact solution is used to derive the eigenvalue equation of a multi-step bar. The new exact approach combining the transfer matrix method and the closed form solution of one step bar is presented. The proposed methods is convenient for solving the entire and partial buckling of one-step and multi-step bars with various end conditions, with or without shear deformation effect, subjected to concentrated axial loads. A numerical example is given explaining the proposed procedure and investigating the effect of shear deformation on the critical buckling force of a multi-step bar.
TL;DR: In this article, a trigonometric series solution for bending moments of the top slab under local distributed load and concentrated load with elastically clamped boundary conditions is presented for single-cell box girders.
Abstract: A new approach is presented for the calculation of moments on top slab in single-cell box girders. Using the classic thin plate theory, trigonometric series solutions for bending moments of the top slab under local distributed load and concentrated load with elastically clamped boundary conditions are derived. A numerical example is given to demonstrate the application of the proposed method.
TL;DR: In this article, a reduced-order modeling technology for vibration control of wind-excited tall buildings is presented and its performance is studied, which is useful when control systems are implemented in civil engineering structures.
Abstract: The design of a structural control system for a tall building may not be easy owing to the large number of degrees of freedom involved. Obviously, it is much easier to design a structural control system for the reduced-order system than for the full-order system. Model reduction is thus useful when control systems are implemented in civil engineering structures. A reduced-order modelling technology for vibration control of wind-excited tall buildings is presented and its performance is studied. The important issues associated with wind-induced vibrations, model condensations and reduced-order control are addressed. Finally, a numerical example, a tall building with an active tuned mass damper or a passive tuned mass damper, is given to show the efficiency of the reduced-order control technique. Copyright © 2003 John Wiley & Sons, Ltd.
01 Aug 2003
TL;DR: In this paper, a practical procedure for the analysis of multi-braced earth retaining structures considering various excavation stages is presented for the first time, taking into account the interactions among pile, soil and bracings, and through stage by stage analysis of the effect of the excavation process on internal forces, support reactions and displacements of a pile.
Abstract: A practical procedure for the analysis of multi-braced earth retaining structures considering various excavation stages is presented in this paper for the first time. Taking into account the interactions among pile, soil and bracings, and through stage by stage analysis of the effect of the excavation process on internal forces, support reactions and displacements of a pile, a computation procedure is proposed based on flexural differential equations for multi-braced earth retaining structures. Comparison is made between the proposed method and the measured data and close agreement has been found. It is noted that the design moment of a pile should be the maximum moment during the entire excavation process (not necessarily the last stage). The proposed method has addressed this issue in the design stage and also provided technical guidance for the construction process. The method is simple and efficient. In fact, the computation can be done manually when the bracings are less than three.
01 Aug 2003
TL;DR: In this article, a generalised finite segment method for the analysis of a skewed multi-rib T-beam is presented, which simplifies a 3D structure into a one-dimensional structure such as a beam for structural analysis.
Abstract: A generalised finite segment method for the analysis of a skewed multi-rib T-beam is presented in this paper. Using the skewed beam element under an inclined coordinate system for the skewed deck and normal beam element for the ribs, a spatial displacement field for the composite structure is constructed. Shear lag effect and local flexure of the deck are taken into consideration in constructing the displacement field, as well as the stiffness of the transverse diaphragm. The formulation of the finite segment is established based on the variational principle. The proposed method simplifies a three-dimensional structure into a one-dimensional structure such as a beam for structural analysis and therefore reduces the computational efforts significantly. Numerical examples are given to illustrate the application of the proposed approach. It is shown through the examples that the results obtained using the proposed finite segment approach are in agreement with the experimental data, verifying the accuracy of ...
TL;DR: In this article, the dye-injection flow visualisation technique was used to investigate the effect of the apex flap on the leading-edge vortex breakdown over a cropped 76°/40° double delta wing.
Abstract: The dye-injection flow visualisation technique was used to investigate the effect of the apex flap on the leading-edge vortex breakdown over a cropped 76°/40° double delta wing. The angle-of-attack of the experimental model varied from 20° to 40°, and the length of the apex flap was 25%c and 50%c respectively
TL;DR: In this article, a finite element with generalized degrees of freedom (FEGDOF) was developed for dynamic analysis of flexural beams and plates with cross-section varying in a continuous or discontinuous manner.
TL;DR: In this article, multi-story buildings with shear-wall structures and with narrow rectangular plane configuration are modeled as a multi-step flexural-shear plate with varying cross-section for buckling analysis.
Abstract: In this paper, multi-story buildings with shear-wall structures and with narrow rectangular plane configuration are modeled as a multi-step flexural-shear plate with varying cross-section for buckling analysis. The governing differential equation of such a plate is established. Using appropriate transformations, the equation is reduced to analytically solvable equations by selecting suitable expressions of the distribution of stiffness. The exact solutions for buckling of such a one-step flexural-shear plate with variable stiffness are derived for several cases. A new exact approach that combines the transfer matrix method and closed from solution of one-step flexural-shear plate with continuously varying stiffness is presented for stability analysis of multi-step non-uniform flexural-shear plate. A numerical example shows that the present methods are easy to implement and efficient.