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CONTENTS
Volume 5, Number 3, September 2016
 

Abstract
The present study deals with the numerical modelling for the one dimensional contaminant transport through saturated homogeneous and stratified porous media using meshfree method. A numerical algorithm based on Element free Galerkin method is developed. A one dimensional form of the advective-diffusive transport equation for homogeneous and stratified soil is considered for the analysis using irregular nodes. A FORTRAN program is developed to obtain numerical solution and the results are validated with the available results in the literature. A detailed parametric study is conducted to examine the effect of certain key parameters. Effect of change of dispersion, velocity, porosity, distribution coefficient and thickness of layer is studied on the concentration of the contaminant

Key Words
contaminant transport; irregular nodes; homogenous and stratified porous media; Meshfree methods; Element free Galerkin method

Address
Rupali S and Sawant Vishwas A: Department of Civil Engineering, IIT Roorkee, Roorkee 247667, India

Abstract
The main purpose of current study is to find the soil effects on natural period of elevated tank. The coupled analytical method is used to assess in this study. The current study presented models which are capable to consider the soil dynamic stiffness changes and fluid- structure interaction effects on natural period of elevated tanks. The basic of mentioned models is extracted from elastic beam and lumped mass theory. The finite element is used to verify the results. It is observed that, external excitation can change the natural period of elevated tanks. Considering the increase of excitation frequency, the natural period will be decreased. The concluded values of natural period in case of soft and very soft soil are more affected from excitation frequency values. The high range of excitation frequency may reduce the natural period values. In addition it is observed that the excitation frequency has no significant effect on convective period compare with impulsive period.

Key Words
ground excitation; analytical model; natural period; elevated tank; impulsive; convective

Address
Pouyan Abbasi Maedeh: International campus, Kharazmi University, No. 49 Mofatteh Ave. Tehran, I.R. Iran

Ali Ghanbari:Faculty of Engineering, Kharazmi University, No. 49 Mofatteh Ave., Tehran, I.R. Iran

Wei Wu: Faculty of Engineering, University of Bodenkultur, Wien, Austria

Abstract
A numerical model for fluid-structure interactions (abbr. FSI) is presented in the context of sloshing effects in movable, partially filled tanks to improve understanding of interactions between the fluid and the dynamics of a tank flexibly attached to a vehicle. The purpose of this model is to counteract the penalizing impact of the added mass effect on classical partitioned FSI coupling scheme: the proposed investigation is based on an added mass corrected version of the classical strongly coupled partitioned scheme presented in (Song et al. 2013). Results show that this corrected version systematically allows convergence to the coupled solution. In the rare cases where convergence is already obtained, the corrected version significantly reduces the number of iterations required. Finally, it is shown that the convergence limit imposed by added mass effect for the non-corrected coupling scheme, is directly dependent on the aspect ratio of the fluid domain and highly related to the precision order of the temporal discretization scheme.

Key Words
fluid-structure interaction; added mass; sloshing; coupling partitioned scheme

Address
Emmanuel Lefrançois and Anaïs Brandely: Roberval Laboratory CNRS UMR 7337, Universite de Technologie de Compiegne-Sorbonne Universites, CS 60319, 60203 Compiegne, France
Stéphane Mottelet: TIMR Laboratory EA 4297, Universite de Technologie de Compiegne-Sorbonne Universites, CS 60319, 60203 Compiegne, France

Abstract
To investigate the surface effects on vibration of embedded circular curved nanosize beams, nonlocal elasticity model is used in combination with surface properties including surface elasticity, surface tension and surface density for modeling the nano scale effect. The governing equations are determined via the energy method. An-alytically Navier method is utilized to solve the governing equations for simply supported at both ends. Solving these equations enables us to estimate the natural frequency for circular curved nanobeam including Winkler and Pasternak elastic foundations. The results determined are verified by comparing the results by available ones in literature. The effects of various parameters such as nonlocal parameter, surface properties, Winkler and Pasternak elastic foundations and opening angle of circular curved nanobeam on the natural frequency are suc-cessfully studied. The results reveal that the natural frequency of circular curved nanobeam is significantly in-fluenced by these effects.

Key Words
vibration; curved nanobeam; surface effects; elastic foundation

Address
Farzad Ebrahimi and Mohsen Daman: Department of Mechanical Engineering, Faculty of Engineering, Imam Khomeini International University, Qazvin, Iran

Abstract
A two new high-order shear deformation theory for bending analysis is presented for a simply supported, functionally graded plate with porosities resting on an elastic foundation. This porosities may possibly occur inside the functionally graded materials (FGMs) during their fabrication, while material properties varying to a simple power-law distribution along the thickness direction. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theories presented are variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. It is established that the volume fraction of porosity significantly affect the mechanical behavior of thick function ally graded plates. The validity of the two new theories is shown by comparing the present results with other higher-order theories. The influence of material parameter, the volume fraction of porosity and the thickness ratio on the behavior mechanical P-FGM plate are represented by numerical examples.

Key Words
functionally graded material; higher-order theory; volume fraction of porosity; winkler-pasternak elastic foundation

Address
Tahar Hassaine Daouadji and Belkacem Adim:
1) Département de génie civil, Université Ibn Khaldoun Tiaret; BP 78 Zaaroura, 14000 Tiaret, Algérie
2) Laboratoire de Géomatique et Développement Durable, Université Ibn Khaldoun de Tiaret Algérie
Rabia Benferhat: Laboratoire de Géo-matériaux, Département de Génie Civil, Université de Chlef 02000, Algérie


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