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CONTENTS
Volume 5, Number 2, June 2012
 

Abstract
There is relatively little numerical study on the behavior of eccentrically loaded high strength rectangular concrete-filled steel tubular (CFST) slender beam-columns with large depth-to-thickness ratios, which may undergo local and global buckling. This paper presents a multiscale numerical model for simulating the interaction local and global buckling behavior of high strength thin-walled rectangular CFST slender beam-columns under eccentric loading. The effects of progressive local buckling are taken into account in the mesoscale model based on fiber element formulations. Computational algorithms based on the Muller

Key Words
concrete-filled steel tubes; high strength materials; inelastic analysis; local buckling.

Address
Vipulkumar Ishavarbhai Patel and Qing Quan Liang: School of Engineering and Science, Victoria University, PO Box 14428, Melbourne, VIC 8001, Australia
Muhammad N.S. Hadi: School of Civil, Mining and Environmental Engineering, University of Wollongong, Wollongong, NSW 2522, Australia

Abstract
The study of rigid roadway pavement under dynamic traffic loads with variable velocity is investigated in this paper. Rigid roadway pavement is modeled as a rectangular damped orthotropic plate supported by elastic Pasternak foundation. The boundary supports of the plate are the steel dowels and tie bars which provide elastic vertical support and rotational restraint. The natural frequencies of the system and the mode shapes are solved using two transcendental equations, obtained from the solution of two auxiliary Levy\'s type problems, known as the Modified Bolotin Method. The dynamic moving traffic load is expressed as a concentrated load of harmonically varying magnitude, moving straight along the plate with a variable velocity. The dynamic response of the plate is obtained on the basis of orthogonality properties of eigenfunctions. Numerical example results show that the velocity and the angular frequency of the loads affected the maximum dynamic deflection of the rigid roadway pavement. It is also shown that a critical speed of the load exists. If the moving traffic load travels at critical speed, the rectangular plate becomes infinite in amplitude.

Key Words
rigid roadway pavement; elastic foundation; auxiliary Levy

Address
S.W. Alisjahbana: Faculty of Engineering and Informatics, Universitas Bakrie, Indonesia
W. Wangsadinata: President Director, PT Wiratman and Associates, Indonesia

Abstract
Nanowires (NWs) have attracted intensive researches owing to the broad applications that arise from their remarkable properties. Over the last decade, immense numerical studies have been conducted for the numerical investigation of mechanical properties of NWs. Among these numerical simulations, the molecular dynamics (MD) plays a key role. Herein we present a brief review on the current state of the MD investigation of nanowires. Emphasis will be placed on the FCC metal NWs, especially the Cu NWs. MD investigations of perfect NWs

Key Words
mechanical properties; nanowires; molecular dynamic simulation; defects; surface effects.

Address
Y.T. GU and H.F. ZHAN: School of Engineering Systems, Queensland University of Technology, Brisbane 4001, Australia
Xu XU: School of Mathematics, Jilin University, Changchun 130012, China

Abstract
We study a radial basis function collocation method (RBFCM) to discretize a coupled nonlinear Schrodinger equation (CNLSE) that governs a two dimensional rotating Bose-Einstein condensate (BEC) with an angular momentum rotation term. We exploit a RBFCM-continuation method (RBFCM-CM) to trace the solution curve of the CNLSE. We compare the performance of the RBFCMCM with the FEM-CM. We observe that the RBFCM-CM is very robust in a coarse grid for resolving the ground state solution with many vortices when the angular momentum rotation is close to the limit. Numerical results demonstrate the efficiency and accuracy of the RBFCM-CM for computing the superfluid density of the ground level of the BEC.

Key Words
radial basis collocation; inverse multiquadric; meshless; rotating bec; continuation method; vortex lattice; nonlinear schrodinger equation.

Address
Y.T. Shih, C.C. Tsai and K.T. Chen: Department of Applied Mathematics, National Chung Hsing University, Taichung 40227, Taiwan

Abstract
The thin-plate structure and the box-beam structure are two typical welded structures in railway vehicles. Because of their structure complexity, bigger size and multi-seams, welding residual distortion which occur in welding process bring unfavorable effect on the quality of welding products manufacturing and service. As a result, welding distortion forecasting and control become an important and urgent research topic in railway vehicles. In this paper, three different numerical methods are presented corresponding to three typical types of welded structures of railway vehicles and welding deformation are simulated. Consistence of numerical results and experimental data proves the correctness of models and feasibility of simulation methods.

Key Words
thin-plate structure; box-beam structure; railway vehicle; welding distortion; numerical simulation methods.

Address
Li Ya-na, Li Cheng-tao and Xie Su-ming: Traffic and Transportation School, Dalian Jiao tong University, Dalian, China
Yuan Bin: Transportation Equipments and Ocean Engineering College, Dalian Maritime University, Dalian, China

Abstract
The dilatancy of granular materials has significant influence on its mechanical behaviors. The dilation angle is taken as a constant in conventional associated or non-associated flow rules based on Drucker-Prager yields theory. However, various experimental results show the dilatancy changes during progressive failure of granular materials. A non-associated flow rule with evolution of dilation angle is adopted in this study, and Cosserat continuum theory is used to describe the behaviors of granular materials for considering to some extent the its internal structure. Numerical examples focus on the bearing capacity and localization of granular materials, and results illustrate the capability and performance of the presented model in modeling the effect on failure behavior of granular materials.

Key Words
granular materials; Cosserat continuum model; dilation angle; bearing capacity; strain localization.

Address
Xihua Chu, Cun Yu and Yuanjie Xu: Department of engineering mechanics, Wuhan University, Wuhan 430072, P.R. China


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