Masoud Asgari
Faculty of Mechanical Engineering, K. N. Toosi University of Technology,
Pardis Street, Molla-Sadra Avenue, Vanak Square, Tehran, Iran,
e-mail: asgari@kntu.ac.ir

TWO DIMENSIONAL FUNCTIONALLY GRADED
MATERIAL FINITE THICK HOLLOW CYLINDER
AXISYMMETRIC VIBRATION MODE SHAPES ANALYSIS
BASED ON EXACT ELASTICITY THEORY


Abstract. A thick hollow cylinder with finite length made of twodimensional functionally graded material (2D-FGM) is considered and its natural modes are determined, based on great importance of mode shapes information in order to understand vibration behaviour of structures. Three dimensional theory of elasticity implemented for problem formulation, since mode shapes of a thick cylinder are three dimensional even with axisymmetric conditions. The axisymmetric conditions are assumed for the 2D-FGM cylinder. The material properties of the cylinder are varied in the radial and axial directions, with power law functions. Effects of volume fraction distribution on the different types of symmetric mode shapes configuration and vibration behaviour of a simply supported cylinder are analyzed. Three dimensional equations of motion areused and the eigen value problem is developed, based on direct variation method.


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Y. J. Wang
College of Engineering, Nanjing Agricultural University, Nanjing 210031, China
State key Laboratory of Mechanics and Control of Mechanical Structures,
Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China
C. F.Gao, H. P. Song, S. C. Xing
State key Laboratory of Mechanics and Control of Mechanical Structures,
Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China,
e-mail: cfgao@nuaa.edu.cn

THE GENERALIZED TWO DIMENSIONAL
THERMAL-ELECTRO-ELASTIC SOLUTION FOR THE
CRACKED-HALF-ELLIPTICAL-HOLE PROBLEM IN A
HALF PLANE


Abstract. The half elliptical hole with an edge crack in a thermopiezo electric material is studied by using the complex variable method. First, the mapping function which maps the outside of the elliptical hole and the crack in the right half plane into the outside of a circular hole in a full plane is given by the method of conformal mapping. Then, the complex potential functions and the field intensity factors (FIF) are presented according to the boundary conditions, respectively. Some useful results can be found by numerical analysis: 1) The influence of the heat flux on FIF depends on the model of the crack; 2) The shape and the size of the hole possess a significant effect on the field distribution at the crack tip.

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Mitul Islam
203, B.T. Road, Indian Statistical Institute,
Kolkata 700108, India,
e-mail: mitul.islam@gmail.com
Nurul Islam
Ramakrishna Mission College (Autonomous), Narendrapur,
Kolkata 700103, India,
e-mail: dr.i.nurul@gmail.com
Svetoslav Nikolov
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
University of Transport, 158, G. Milev St., 1574 Sofia, Bulgaria,
e-mail: s.nikolov@imbm.bas.bg

ADAPTIVE CONTROL AND SYNCHRONIZATION OF
SPROTT J SYSTEM WITH ESTIMATION OF FULLY
UNKNOWN PARAMETERS


Abstract. This communication develops an adaptive scheme for control and synchronization of Sprott J system with fully unknown parameters. The scheme provides an elegant strategy of designing estimators for identification of the unknown parameters of the underlying dynamical system. Adaptive control and update laws are proposed to globally stabilize the chaotic Sprott J system. A pair of identical Sprott J systems with unknown parameters are globally synchronized with the help of adaptive control and parameter update laws. The results are established using LaSalle invariance principle, which lays down weaker restrictions on the derivatives of the Lyapunov function, and producing more general results. All the results obtained in the paper are global in nature. Numerical simulations are performed to illustrate the validity and effectiveness of the proposed adaptive control and synchronization scheme in the context of the Sprott J system. The parameter identification capability of the scheme is also explored.

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I.-K. Fontara, F. Wuttke
Institute of Applied Geo-science,
Christian-Albrechts-University of Kiel, Germany,
e-mails: fontara@gpi.uni-kiel.de, fw@gpi.uni-kiel.de
S. Parvanova
University of Architecture, Civil Engineering and Geodesy,
Faculty of Structural Engineering, Structural Mechanics,
1, Hr. Smirnenski Blvd, 1046 Sofia, Bulgaria,
e-mail: slp_y@abv.bg
P. Dineva
Institute of Mechanics, Bulgarian Academy of Sciences,
Acad. G. Bonchev St., Bl. 4, 1113 Sofia, Bulgaria,
e-mail: dineva@gmail.com


WAVE PROPAGATION DUE TO AN EMBEDDED
SEISMIC SOURCE IN A GRADED HALF-PLANE WITH
RELIEF PECULIARITIES.
PART II: PARAMETRIC STUDY

Abstract. The mechanical model and the accompanied computational technique, based on the boundary integral equation method (BIEM) and Green’s function for continuously inhomogeneous half-plane were described in the first part of this work. 2D elastodynamic problem for quadratically inhomogeneous and heterogeneous geological area was defined in the first part of our work. The aim of the current second part is to demonstrate the accuracy and the convergence of the proposed computational tool. Furthermore, subsequent extensive parametric study will illustrate, that the seismic wave field is a complex result of mutual play of different key factors as free-surface relief, wave characteristics, as frequency and wavelength, seismic source properties, type and characteristics of the material gradient, existence of different type of heterogeneities and their interactions.


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Ivanka Zheleva
Ruse University,
8 Studentska str., 7017 Ruse, Bulgaria,
e-mail: izheleva@uni-ruse.bg

TEMPERATURE NON-HOMOGENEIETIES IN A
CATALYTIC REACTOR WITH A PERIODIC CHANGE IN
THE DIRECTION OF THE REACTION MIXTURE FEED


Abstract. Temperature non-homogeneities in a catalytic reactor with periodic change in the direction of the reaction mixture feed is investigated in the present work. The temperature of the reaction mixture is described using a numerical algorithm for simulation of the work of the catalytic reactor, graphically shown and commented. The influence of the higher catalyst layer porosity in the wall area upon the temperature distribution in the reactor is studied. The existence of two different regimes is shown – a high temperature one in the middle part of the layer and a low temperature one in the high porosity area of the layer in contact with the reactor wall. This leads to not very effective usage of the catalyst in these parts of the catalyst layer in the reactor. This simulation can be used for better understanding and controlling of the examined catalytic process.

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Bahattin ˙I ¸scan
Department of Mechanics, Vocational School of Higher Education,
Batman University, Batman 72060, Turkey,
e-mail: bahattin.iscan@batman.edu.tr

STRESS ANALYSIS OF LAP JOINTS WITH EMBEDDED
COVER PLATE

Abstract. In this study, the effects of the bonding joints that are partly embedded in the adherent on the tensile behaviour of reinforcing plate adhesive joint have been investigated by 2D finite element method. In the study, the SBT 9244 material was used as the adhesive, and the adherent was the AA2024-T3 material. Three different models were built for the height of the embedded part in the adherent (a) and five models for the length of the embedded part (b), while three models were built for the total overlap length (c). Results showed that with the increase of the height of the embedded part and total overlap length, the strength of the joint was considerably increased. The increase of the length of the embedded part was initially led to an increase in the strength of the joints but after 0.25 value of the b/c the strength was reduced.


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IN MEMORIAM
DR. VIJAY KUMAR VERMA