Techno Press
Tp_Editing System.E (TES.E)
Login Search


csm
 
CONTENTS
Volume 10, Number 1, February 2021
 

Abstract
Composite nature of the masonry structures in general causes complex and non-linear behaviour, especially in intense vibration conditions. The presence of different types and forms of structural elements and different materials is a major problem for the analysis of these type of structures. For this reason, the analysis of the behaviour of masonry structures requires a combination of experimental tests and non-linear mathematical modelling. The famous UNESCO Heritage Old Bridge in Mostar was selected as an example for the analysis of the global behaviour of reinforced stone arch masonry bridges. As part of the experimental research, a model of the Old Bridge was constructed in a scale of 1:9 and tested on a shaking table platform for different levels of seismic excitation. Non-linear mathematical modelling was performed using a combined finite-discrete element method (FDEM), including the effect of connection elements. The paper presents the horizontal displacement of the top of the arch and the failure mechanism of the Old Bridge model for the experimental and the numerical phase, as well as the comparison of the results. This research provided a clearer insight into the global behaviour of stone arch masonry structures reinforced with steel clamps and steel dowels, which is significant for the structures classified as world cultural heritage.

Key Words
combined finite-discrete element methods; reinforced masonry arch structures; steel clamps and dowels

Address
Mladen Kustura: Faculty of Civil Engineering, University of Mostar, Mostar, Bosnia and Herzegovina
Hrvoje Smoljanovic: Faculty of Civil Engineering, Architecture and Geodesy, University of Split, Split, Croatia
Zeljana Nikolic: Faculty of Civil Engineering, Architecture and Geodesy, University of Split, Split, Croatia
Lidija Krstevska: Institute of Earthquake Engineering and Engineering Seismology – IZIIS, University Sts. Cyril and Methodius, Skopje, Republic of North Macedonia

Abstract
This work is an attempt to design a dynamic model for a non local bio-thermoelastic medium with diffusion. The system of governing equations are formulated in terms of displacement vector field, chemical potential and the tissue temperature in the context of non local dual phase lag (NL DPL) theories of heat conduction and mass diffusion. Based on this considered model, we study the fundamental solution and propagation of plane harmonic waves in tissues. In order to analyze the behavior of the NL DPL model, we construct basic theorem in the terms of elementary function which determine the existence of three longitudinal and one transverse wave. The effects of various parameters on the characteristics of waves i.e., phase velocity and attenuation coefficients are elaborated by plotting various figures of physical quantities in the later part of the paper.

Key Words
non local; bio-thermoelastcity; diffusion; phase lag; fundamental solution; wave propagation

Address
Rajneesh Kumar: Department of Mathematics, Kurukshetra University, Kurukshetra - 136119 Haryana, India
Suniti Ghangas: Department of Mathematics, M.D.S.D. Girls College, Ambala - 134003, Haryana, India
Anil K. Vashishth: Department of Mathematics, Kurukshetra University, Kurukshetra - 136119 Haryana, India

Abstract
The present paper is concerned with the study of nonlinear ultrasonic waves in a magneto thermo (MT) elastic armchair single-walled carbon nanotube (ASWCNT) resting on polymer matrix. The analytical formulation is developed based on Eringen's nonlocal elasticity theory to account small scale effect. After developing the formal solution of the mathematical model consisting of partial differential equations, the frequency equations have been analyzed numerically by using the nonlinear foundations supported by Winkler-Pasternak model. The solution is obtained by ultrasonic wave dispersion relations. Parametric work is carried out to scrutinize the influence of the non local scaling, magneto-mechanical loadings, foundation parameters, various boundary condition and length on the dimensionless frequency of nanotube. It is noticed that the boundary conditions, nonlocal parameter, and tube geometrical parameters have significant effects on dimensionless frequency of nano tubes. The results presented in this study can provide mechanism for the study and design of the nano devices like component of nano oscillators, micro wave absorbing, nano-electron technology and nano-electro- magneto-mechanical systems (NEMMS) that make use of the wave propagation properties of armchair single-walled carbon nanotubes embedded on polymer matrix.

Key Words
nonlocal elasticity; armchair; CNT; Euler-beam theory; NEMS

Address
Rajendran Selvamani: Department of Mathematics, Karunya Institute of Technology and Sciences, Coimbatore-641114, Tamilnadu, India
M. Mahaveer Sree Jayan: Department of Mathematics, Karunya Institute of Technology and Sciences, Coimbatore-641114, Tamilnadu, India
Farzad Ebrahimi: Department of Mechanical Engineering, Imam Khomieni International University, Qazvin 34148-96818, Iran

Abstract
The porosity of functionally graded materials (FGM) can affect the static and dynamic behavior of plates, which is important to take this aspect into account when analyzing such structures. The present work aims to study the effect of the distribution shape of porosity on the free vibration response of simply supported FG plate reposed on the Winkler-Pasternak foundation. A refined theory of shear deformation is expanded to study the influence of the distribution shape of porosity on the free vibration behavior of FG plates. The findings showed that the distribution shape of porosity significantly influences the free vibration behavior of thick rectangular FG plates for small values of Winkler-Pasternak elastic foundation parameters.

Key Words
FGM plate; higher-order theory; free vibration behavior; volume fraction of porosity; Winkler-Pasternak elastic foundation

Address
Bekki Hadj, Benferhat Rabia and Tahar Hassaine Daouadji: Laboratory of Geomatics and sustainable development, University of Tiaret, Algeria; Department of Civil Engineering, Ibn Khaldoun University of Tiaret, Algeria

Abstract
In this paper we deal with instability problems of structures under nonconservative loading. It is shown that such class of problems should be analyzed in dynamics framework. Next to analytic solutions, provided for several simple problems, we show how to obtain the numerical solutions to more complex problems in efficient manner by using the finite element method. In particular, the numerical solution is obtained by using a modified Euler-Bernoulli beam finite element that includes the von Karman (virtual) strain in order to capture linearized instabilities (or Euler buckling). We next generalize the numerical solution to instability problems that include shear deformation by using the Timoshenko beam finite element. The proposed numerical beam models are validated against the corresponding analytic solutions.

Key Words
instability problems; non-conservative load; Euler-Bernoulli beam; von Karman strain; Timoshenko beam; shear deformation

Address
Emina Hajdo: Faculty of Civil Engineering, University of Sarajevo, Patriotske lige 30, Sarajevo, BiH, Bosnia and Herzegovina
Rosa Adela Mejia-Nava: Universite de Technologie Compiegne, Laboratoire Roberval de Mecanique, Rue du Dr Schweitzer, 60200 Compiegne, France
Ismar Imamovic: Faculty of Civil Engineering, University of Sarajevo, Patriotske lige 30, Sarajevo, BiH, Bosnia and Herzegovina
Adnan Ibrahimbegovic: Universite de Technologie Compiegne, Laboratoire Roberval de Mecanique, Rue du Dr Schweitzer, 60200 Compiegne, France; Institut Universitaire de France, France


Techno-Press: Publishers of international journals and conference proceedings.       Copyright © 2021 Techno-Press
P.O. Box 33, Yuseong, Daejeon 34186 Korea, Tel: +82-2-736-6800, Fax : +82-2-736-6801, Email: info@techno-press.com