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Volume 29, Number 4, July10 2008

In this study, the new three-dimensional finite element analysis model of guideway structures considering ultra high-speed magnetic levitation train-bridge interaction, in which the various improved finite elements are used to model structural members, is proposed. The box-type bridge deck of guideway structures is modeled by Nonconforming Flat Shell finite elements with six DOF (degrees of freedom). The sidewalls on a bridge deck are idealized by using beam finite elements and spring connecting elements. The vehicle model devised for an ultra high-speed Maglev train is employed, which is
composed of rigid bodies with concentrated mass. The characteristics of levitation and guidance force, which exist between the super-conducting magnet and guideway, are modeled with the equivalent spring
model. By Lagrange?s equations of motion, the equations of motion of Maglev train are formulated. Finally, by deriving the equations of the force acting on the guideway considering Maglev train-bridge
interaction, the complete system matrices of Maglev train-guideway structure system are composed.

Key Words
magnetic levitation train; Maglev train-guideway interaction; guideway structures; dynamic analysis; finite element analysis.

Myung-Kwan Song: Renewable Energy Development Team, Corporate R&D Institute, Doosan Heavy Industries & Construction, 463-1 Jeonmin-dong, Yuseong-gu, Daejeon 305-811, Korea
Yozo Fujino: Dept. of Civil Engineering, The University of Tokyo, Tokyo 113-8656, Japan

This paper proposed a conceptual design of bascule bridge, which is a new kind of movable bridge with an aim of reducing the weight of superstructure. Compared with the traditional bascule bridge,
the light bascule bridge chooses cable-stayed bridge with inclined pylon as its superstructure; therefore, the functions of balance-weight and structure will fuse into one. Otherwise, it adopts moving
counterweight to adjust its center of gravity (CG) to open or close the bridge. In order to lighten the superstructure, it uses contact springs to auxiliary retract, and intelligent prestressing system (IPS) to
control the main girder\'s deformation. Simultaneously the vibration control scheme of structure is discussed. Starting from establishing the mechanical model of bridge, this article tries to analyze the
conditions that the design parameters of structure and attachments should satisfy to. After the design procedure was presented, an example was also adopted to explain the primary design process of this kind

Key Words
bridge engineering; bascule bridge; cable-stayed bridge; retractable structure; intelligent prestressing system; special structure; parameter analysis.

Weiwei Xu, Hanshan Ding and Zhitao Lu: College of Civil Engineering, Southeast University, Nanjing 210096, China

In this article, a harmony search algorithm is presented for optimum design of steel frame structures. Harmony search is a meta-heuristic search method which has been developed recently. It is
based on the analogy between the performance process of natural music and searching for solutions of optimization problems. The design algorithms obtain minimum weight frames by selecting suitable
sections from a standard set of steel sections such as American Institute of Steel Construction (AISC) wide-flange (W) shapes. Stress constraints of AISC Load and Resistance Factor Design (LRFD) and
AISC Allowable Stress Design (ASD) specifications, maximum (lateral displacement) and interstorey drift constraints, and also size constraint for columns were imposed on frames. The results of harmony search
algorithm were compared to those of the other optimization algorithms such as genetic algorithm, optimality criterion and simulated annealing for two planar and two space frame structures taken from the
literature. The comparisons showed that the harmony search algorithm yielded lighter designs for the design examples presented.

Key Words
optimum design; harmony search; steel frame structures.

S. O. Degertekin: Department of Civil Engineering, Dicle University, 21280, Diyarbakir, Turkey

In the present study, free vibration analysis of thick annular plates is analyzed by discrete singular convolution method. The Mindlin plate theory is employed. The material is isotropic, homogeneous and obeys Hook?s law. In this paper, discrete singular convolution method is used for discretization of equations of motion. Axisymmetric frequency values are presented illustrating the effect of radius ratio and thickness to radius ratio of the annular plate. The influence of boundary conditions on the frequency characteristics is also discussed. Comparing results with those in the literature validates the present analysis. It is shown that the obtained results are very accurate by this approach.

Key Words
free vibration; discrete singular convolution; frequency; annular plate; thick plate.

Omer Civalek: Akdeniz University, Faculty of Engineering, Civil Engineering Department, Division of Mechanics, Antalya, Turkiye
Hakan Ersoy: Akdeniz University, Faculty of Engineering, Mechanical Engineering Department, Division of Mechanics, Antalya, Turkiye

With respect to thermal barrier coating, the analysis of interface cohesion and residual stress is important to the life of TBC from mechanical view point. Up to now, there is not a model of describing
interface cohesion. In the paper, we give a simple model of computing residual stress and study the residual stress of TBC with ANSYS. The distribution of the residual stress in different interface topography and the relationship between the residual stress and the interface topography dimension are presented.

Key Words
thermal barrier coatings; numerical simulation; residual stress; interface topography.

Guo-Feng Yao and Hong-Mei Ma: College of Mechanical Science and Engineering, Nanling Campus, Jilin University, Changchun 130025, China
Lin-wen Zhang: Jilin College of Traffic Profession Technique, Changchun 130021, China

The equation of motion of a one way (vertical) spanning strip wall, as an assembly of two rigid bodies, is presented. Only one degree of freedom is needed to completely describe the wall response
as the bodies are assumed to be perfectly rectangular and are allowed to rock but not to slide horizontally. Furthermore, no arching action occurs since vertical motion of the upper body is not restrained. Consequently, the equation of motion is nonlinear, with non constant coefficients and a Coriolis acceleration term. Phenomena associated with overburden to self weight ratio, motion triggering,
impulsive energy dissipation, amplitude dependency of damping and period of vibration, and scale effect are discussed, contributing to a more complete understanding of experimental observations and to an
estimation of system parameters based on the wall characteristics, such as intermediate hinge height and energy damping, necessary to perform nonlinear time history analyses. A comparison to a simple standing, or parapet, wall is developed in order to better highlight the characteristics of this assembly.

Key Words
rocking response; threshold acceleration; impulsive energy dissipation; amplitude dependency; scale effect.

Luigi Sorrentino and Renato Masiani: Structural and Geotechnical Engineering Department, Sapienza University, Rome, Italy
Michael C. Griffith: School of Civil, Environmental and Mining Engineering, The University of Adelaide, Adelaide, South Australia, Australia

This paper deals with the buckling and postbuckling responses and the progressive failure of square symmetric laminates with rectangular cutouts under uniaxial compression. A detailed investigation
is made to show the effects of cutout size and cutout aspect ratio on prebuckling and postbuckling responses, failure loads and failure characteristics of (+45/.45/0/90)2s, (+45/.45)4s and (0/90)4s laminates. The 3-D Tsai-Hill criterion is used to predict the failure of a lamina while the onset of delamination is predicted by the interlaminar failure criterion. In addition, the effects of boundary conditions on buckling load, failure loads, failure modes and maximum transverse deflection for a (+45/.45/0/90)2s laminate with and without cutout have also been presented. It is concluded that square laminates with small square cutouts have more postbuckling strength than without cutout, irrespective of boundary conditions.

Key Words
buckling; composite laminates; cutouts; failure; postbuckling; strength.

S. B. Singh and Dinesh Kumar: Birla Institute of Technology and Science Pilani, Pilani-333031, India

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