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Emerging Sources Citation Index

DOMINIK KERN

SERGIO CONDE MARTÍN

1 TU Chemnitz, Reichenhainer Straße 70, 09126 Chemnitz, Germany

2 ETSI Industriales, Technical University of Madrid, Madrid, Spain

3 ETSI de Caminos, Canales y Puertos, Technical University of Madrid, Spain

[Received 7 November 2017. Accepted 24 November 2017]

PERFORMANCE
ASSESSMENT OF VARIATIONAL

INTEGRATORS FOR THERMOMECHANICAL PROBLEMS

INTEGRATORS FOR THERMOMECHANICAL PROBLEMS

ABSTRACT: Structure-preserving
integrators are in the focus of ongoing research because of their
distinguished features of robustness and long time stability. In
particular, their formulation for coupled problems that include
dissipative mechanisms is still an active topic. Conservative
formulations, such as the thermo-elastic case without heat conduction,
fit well into a variational framework and have been solved with
variational integrators, whereas the inclusions of viscosity and heat
conduction are still under investigation. To encompass viscous forces
and the classical heat transfer (Fourier’s law), an extension of
Hamilton’s principle is required. In this contribution we derive
vari-ational integrators for thermo-viscoelastic systems with classical
heat transfer. Their results are compared for two discrete model
problems vs. energy-entropy-momentum methods.

KEY WORDS: Variational integrators, energy-entropy-momentum methods, viscoelasticity, thermomechanical coupling, heat transfer.

KEY WORDS: Variational integrators, energy-entropy-momentum methods, viscoelasticity, thermomechanical coupling, heat transfer.

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TSVIATKO V. RANGELOV^{1} , PETIA
S. DINEVA^{2} ,

GEORGE D. MANOLIS^{ 3}

1 Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria

2 Institute of Mechanics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria

3 Department of Civil Engineering, Aristotle University, Thessaloniki, GR-54124, Greece

[Received 31 October 2017. Accepted 11 January 2018]

GEORGE D. MANOLIS

1 Institute of Mathematics and Informatics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria

2 Institute of Mechanics, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria

3 Department of Civil Engineering, Aristotle University, Thessaloniki, GR-54124, Greece

[Received 31 October 2017. Accepted 11 January 2018]

DYNAMIC RESPONSE OF A CRACKED
VISCOELASTIC

ANISOTROPIC PLANE USING BOUNDARY ELEMENTS AND

FRACTIONAL DERIVATIVES

ANISOTROPIC PLANE USING BOUNDARY ELEMENTS AND

FRACTIONAL DERIVATIVES

ABSTRACT: The aim of this
study is to develop an efficient numerical technique using the
non-hypersingular, traction boundary integral equation method (BIEM)
for solving wave propagation problems in an anisotropic, viscoelastic
plane with cracks. The methodology can be extended from the macro-scale
with certain modifications to the nano-scale. Furthermore, the proposed
approach can be applied to any type of anisotropic material insofar as
the BIEM formulation is based on the fundamental solution of the
governing wave equation derived for the case of general anisotropy. The
following examples are solved: (i) a straight crack in a viscoelastic
orthotropic plane, and (ii) a blunt nano-crack inside a material of the
same type. The mathematical modelling effort starts from linear
fracture mechanics, and adds the fractional derivative concept for
viscoelastic wave propagation, plus the surface elasticity model of M.
E. Gurtin and A. I. Murdoch, which leads to nonclassical boundary
conditions at the nano-scale. Conditions of plane strain are assumed to
hold. Following verification of the numerical scheme through comparison
studies, further numerical simulations serve to investigate the
dependence of the stress intensity factor (SIF) and of the stress
concentration factor (SCF) that develop in a cracked inhomogeneous
plane on (i) the degree of anisotropy, (ii) the presence of
viscoelasticity, (iii) the size effect with the associated surface
elasticity phenomena, and (iv) finally the type of the dynamic
disturbance propagating through the bulk material.

KEY WORDS : In-plane waves, viscoelasticity, fractional derivatives, anisotropy, cracks, nano-scale, surface elasticity, boundary elements, SIF, SCF.

KEY WORDS : In-plane waves, viscoelasticity, fractional derivatives, anisotropy, cracks, nano-scale, surface elasticity, boundary elements, SIF, SCF.

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M. MUTHTAMILSELVAN

1 Department of Mathematics, Bharathiar University, Coimbatore-641046, India

2 Department of Mathematics, Kongu Engineering College, Perundurai, Erode-638052, India

[Received 4 January 2017. Accepted 6 January 2018]

A TILTED LORENTZ FORCE EFFECT ON
POROUS MEDIA

FILLED WITH NANOFLUID

FILLED WITH NANOFLUID

ABSTRACT: This
paper is intended to investigate the effects of an inclined magnetic
field on the mixed convection flow in a lid-driven porous enclosure
filled with nanofluid. Both the left and right vertical walls of the
cavity are thermally insulated while the bottom and top horizontal
walls are maintained at constant but different temperatures. The
governing equations are solved numerically by using finite volume
method on a uniformly staggered grid system. The computational results
are obtained for various combinations of Richardson number, Darcy
number, Hartmann number, inclination angle of magnetic field, and solid
volume fraction. It is found that the presence of magnetic field
deteriorates the fluid flow, which leads to a significant reduction in
the overall heat transfer rate. The inclination angle of magnetic field
plays a major role in controlling the magnetic field strength and the
overall heat transfer rate is enhanced with the increase of inclination
angle of magnetic field. Adding the nanoparticles in the base fluid
significantly increases the overall heat transfer rate in the porous
medium whether the magnetic field is considered or not.

KEY WORDS: Mixed convection; porous cavity; nanofluid; inclined magnetic field.

KEY WORDS: Mixed convection; porous cavity; nanofluid; inclined magnetic field.

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R.V.M.S.S. KIRAN KUMAR , S.V.K. VARMA

Department of Mathematics, Sri Venkateswara University, Tirupati-517502, A. P, India

[Received 8 September 2017. Accepted 21 November 2017]

MHD
BOUNDARY LAYER FLOW OF NANOFLUID THROUGH

A POROUS MEDIUM OVER A STRETCHING SHEET WITH

VARIABLE WALL THICKNESS: USING

CATTANEO–CHRISTOV HEAT FLUX MODEL

A POROUS MEDIUM OVER A STRETCHING SHEET WITH

VARIABLE WALL THICKNESS: USING

CATTANEO–CHRISTOV HEAT FLUX MODEL

ABSTRACT: The
hydromagnetic nanofluid flow over a stretching sheet in a porous medium
with variable wall thickness in the presence of Brownian motion and
thermophoresis is investigated. The heat transfer characteristics with
variable conductivity are explored by using Cattaneo-Christov heat flux
model. The governing non-linear ordinary differential equations are
solved by using boundary value problem default solver in MATLAB bvp4c
package. The impact of various important flow parameters on velocity,
temperature and nanoparticle concentration as well as the friction
factor coefficient and the rate of heat and mass transfer coefficients
are presented and discussed through graphs and tables. It is found that
the fluid velocity is accelerated with an increase in wall thickness
parameter for n > 1, while the reverse trend is observed for n <
1.

KEY WORDS : Nanofluid flow; Magnetic field; Porous medium; Wall thickness parameter; variable thermal conductivity and molecular diffusivity.

KEY WORDS : Nanofluid flow; Magnetic field; Porous medium; Wall thickness parameter; variable thermal conductivity and molecular diffusivity.

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BALJEET SINGH

1 Department of Mathematics, Post Graduate Government College, Sector 11, Chandigarh, India

2 Department of Mathematics, Maharishi Dayanand University, Rohtak, India

[Received 16 October 2017. Accepted 10 January 2018]

ROTATIONAL
EFFECTS ON PROPAGATION OF RAYLEIGH

WAVE IN A MICROPOLAR PIEZOELECTRIC MEDIUM

WAVE IN A MICROPOLAR PIEZOELECTRIC MEDIUM

ABSTRACT: In
this paper, the governing equations of a linear, homogeneous and
transversely isotropic rotating micropolar piezoelectric medium are
solved for surface wave solutions. The appropriate solutions satisfying
the radiation conditions are obtained in a half-space. These solutions
are applied to suitable boundary conditions at the free surface of the
half- space. A frequency equation for Rayleigh wave is obtained for
both charge free and electrically shorted cases. Using iteration
method, the non-dimensional wave speed of Rayleigh wave is computed for
relevant material constants modelling the medium. The effects of
rotation, piezoelectricity, frequency and material parameters are
observed graphically on the propagation speed.

KEY WORDS : Micropolar, piezoelectric, rayleigh wave, rotation, iteration method.

KEY WORDS : Micropolar, piezoelectric, rayleigh wave, rotation, iteration method.

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