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CONTENTS
Volume 1, Number 2, June 2012
 

Abstract
Paper presents an improved solution algorithm based on Finite Element Method to analyse piled raft foundation. Piles are modelled as beam elements with soil springs. Finite element analysis of raft is based on the classical theory of thick plates resting on Winkler foundation that accounts for the transverse shear deformation of the plate. Four node, isoparametric rectangular elements with three degrees of freedom per node are considered in the development of finite element formulation. Independent bilinear shape functions are assumed for displacement and rotational degrees of freedom. Effect of raft thickness, soil modulus and load pattern on the response is considered. Significant improvement in the settlements and moments in the raft is observed.

Key Words
pile; raft; thick plate; winkler foundation; load pattern

Address
V.A. Sawant, S.V. Pawar and K.B. Ladhane :Indian Institute of Technology Roorkee, India


Abstract
In this paper a bridge flutter prediction is performed by using advanced numerical simulation. Two novel approaches were developed simultaneously by utilizing the ANSYS v12.1 commercial software package. The first one is a fluid-structure interaction simulation involving the three-dimensional elastic motion of a bridge deck and the fluid flow around it. The second one is an updated forced oscillation technique based on the dynamic mode shapes of the bridge. An aeroelastic wind tunnel model was constructed in order to validate the numerical results. Good agreement between the numerical results and the measurements proves the applicability of the novel methods in bridge flutter assessment.

Key Words
bridge deck flutter; fluid-structure interaction (FSI); modal derivatives method

Address
Gergely Szabo and Jozsef Gyorgyi : Department of Structural Mechanics, Budapest University of Technology and Economics, Hungary
Gergely Kristof :Department of Fluid Mechanics, Budapest University of Technology and Economics, Hungary

Abstract
This paper presents analytical approximate solutions for the initial post-buckling deformation of the pipes in oil and gas wells. The governing differential equation with sinusoidal nonlinearity can be reduced to form a third-order-polynomial nonlinear equation, by coupling of the well-known Maclaurin series expansion and orthogonal Chebyshev polynomials. Analytical approximations to the resulting boundary condition problem are established by combining the Newton\'s method with the method of harmonic balance. The linearization is performed prior to proceeding with harmonic balancing thus resulting in a set of linear algebraic equations instead of one of non-linear algebraic equations, unlike the classical method of harmonic balance. We are hence able to establish analytical approximate solutions. The approximate formulae for load along axis, and periodic solution are established for derivative of the helix angle at the end of the pipe. Illustrative examples are selected and compared to \"reference\" solution obtained by the shooting method to substantiate the accuracy and correctness of the approximate analytical approach.

Key Words
analytical approximation; buckling; shooting method

Address
Yongping Yu and Youhong Sun : College of Construction Engineering, Jilin University, Changchun 130021, P.R. China
Yucen Han : School of Mathematical Sciences, Dalian University of Technology, Dalian 116024, P.R. China

Abstract
Macroscopic hot spots formed due to the large thermal gradients at the surface of the disc brake rotor, make the rotor to fail or wear out early. Thermo-elastic deformation results in contact concentration, leading to the non uniform distribution of temperature making the disc susceptible to hot spot formation. The formation of one hot spot event will predispose the system to future hot spotting at the same location. This leads to the complete thermo-elastic instability in the disc brakes; multitude parameters are responsible for the thermo elastic instability. The predominant factor is the sliding velocity and above a certain sliding velocity the instability of the brake system occurs and hot spots is formed in the surface of the disc brake. Commercial finite element package ABAQUS is used to find the temperature distribution and the result is validated using Rowson

Key Words
macroscopic hot spots; thermo elastic instability; Rowson

Address
E. Ramkumar and M.M. Mayuram : Department of Mechanical Engineering, IIT Madras, Chennai, India

Abstract
A method for the analysis of wave scattering in 3-D elastic full space is developed by means of the coupled boundary-volume integral equation, which takes into account the effects of both the boundary of inclusions and the uctuation of the wave field. The wavenumber domain formulation is used to construct the Krylov subspace by means of FFT. In order to achieve the wavenumber domain formulation, the boundary-volume integral equation is transformed into the volume integral equation. The formulation is also focused on this transform and its numerical implementation. Several numerical results clarify the accuracy and effectiveness of the present method for scattering analysis.

Key Words
coupled boundary-volume integral equation; fast Fourier transform; elastic wave scattering; wavenumber domain formulation; Krylov subspace iteration technique

Address
Terumi Touhei: Department of Civil Engineering, Tokyo University of Science, 2641 Yamazaki, Noda City 278-8510, Japan

Abstract
A smart beam made of magneto-electro-elastic (MEE) material having piezoelectric phase and piezomagnetic phase, shows the coupling between magnetic, electric, thermal and mechanical under thermal environment. Product properties such as pyroelectric and pyromagnetic are generated in this MEE material under thermal environment. Recently studies have been published on the product properties (pyroelectric and pyromagnetic) for magneto-electro-thermo-elastic smart composite. Hence, the magneto-electro-elastic beam with different volume fractions, investigated under uniform temperature rise is the main aim of this paper, to study the influence of product properties on clamped-free boundary condition, using finite element procedures. The finite element beam is modeled using eight node 3D brick element with five nodal degrees of freedom viz. displacements in the x, y and z directions and electric and magnetic potentials. It is found that a significant increase in electric potential observed at volume fraction of BaTiO3, vf = 0.2 due to pyroelectric effect. In-contrast, the displacements and stresses are not much affected.

Key Words
magneto-electro-elastic; pyroelectric; pyromagnetic; finite element; thermal environment

Address
P. Kondaiah, K. Shankar and N. Ganesan : Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology, Madras, Chennai 600 036, India


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