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CONTENTS | |

Volume 1, Number 2, June 2012 |

- Parametric study of piled raft for three load-patterns V.A. Sawant, S.V. Pawar and K.B. Ladhane

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Abstract; Full Text (3316K) | pages 115-131. |
DOI: 10.12989/csm.2012.1.2.115 |

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

- Advanced flutter simulation of flexible bridge decks Gergely Szabo, Jozsef Gyorgyi and Gergely Kristof

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Abstract; Full Text (12112K) | pages 133-154. |
DOI: 10.12989/csm.2012.1.2.133 |

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

- Analytical approximate solution for Initial post-buckling behavior of pipes in oil and gas wells Yongping Yu, Youhong Sun and Yucen Han

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Abstract; Full Text (1042K) | pages 155-163. |
DOI: 10.12989/csm.2012.1.2.155 |

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

- Coupled temperature-displacement modeling to study the thermo-elastic instability in disc brakes E. Ramkumar and M.M. Mayuram

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Abstract; Full Text (3999K) | pages 165-182. |
DOI: 10.12989/csm.2012.1.2.165 |

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

- A boundary-volume integral equation method for the analysis of wave scattering Terumi Touhei

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Abstract; Full Text (7143K) | pages 183-204. |
DOI: 10.12989/csm.2012.1.2.183 |

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

- Studies on magneto-electro-elastic cantilever beam under thermal environment P. Kondaiah, K. Shankar and N. Ganesan

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Abstract; Full Text (3670K) | pages 205-217. |
DOI: 10.12989/csm.2012.1.2.205 |

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