2021-09-28T18:27:05Z
http://jsm.iau-arak.ac.ir/?_action=export&rf=summon&issue=1135462
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
On The Free Vibration of Doubly Clamped Single-Walled Coiled Carbon Nanotubes: A Novel Size Dependent Continuum Model
F
Darvishi
O
Rahmani
In this paper, the size dependent vibration behavior of doubly clamped single-walled coiled carbon nanotubes (CCNTs) is investigated using nonlocal helical beam model. This model is based on Washizu’s beam theory so that all displacement components of CCNT in the equations of motion are defined at the centroidal principal axis and transverse shear deformations are considered. After deriving the nonlocal free vibration equations, they are solved by the generalized differential quadrature method (GDQM). Then, the natural frequencies and corresponding mode shapes are determined for the clamped-clamped boundary conditions (BCs). After that, a parametric study on the effect of different parameters, including the helix cylinder to the tube diameters ratio , the number of pitches, the helix pitch angle, and the nonlocal parameter on the natural frequencies is conducted. It is worth noting that the results of the proposed method would be useful in the practical applications of CCNTs such as using in nanoelectromechanical systems.
Free vibration
Coiled carbon nanotubs
Helical spring model
Nonlocal elasticity theory
Differential quadrature method
2021
06
01
114
133
http://jsm.iau-arak.ac.ir/article_682454_c5fb614d00ea6ac3be3b8ad4fdf73209.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Comparative Analysis of Energy Absorption Capacity of Single and Nested Metal Matrix Composite Tubes Under Quasi-Static Lateral and Axial Loading
S
Dehghanpour
K
Hosseini Safari
F
Barati
M.M
Attar
In this paper the behavior of nested tube systems under quasi-static compressive loading is investigated. Two nested tube systems with metal matrix composite are subjected to compressive loads so that in the system A the exterior and interior tubes are under axial and lateral loads, respectively but in the system B the exterior and interior tubes are under lateral and axial loads, respectively. Furthermore, these systems behavior are studied numerically. The results show that energy absorption capacity for both of nested tube systems is greater than the sum of energy absorption capacities of two constitutive tubes when loaded individually. Also, it is shown that the absorbed energy for system A is greater than that of system B. In this research the effects of section geometry and the condition of loading (axial or lateral)of thin-walled tubes on energy absorption capacity and the value of the peak load are studied both experimentally and numerically.
Nested tube systems tubes
energy absorption
Metal matrix composite
Quasi-static loading
2021
06
30
134
143
http://jsm.iau-arak.ac.ir/article_682340_596bab8015941ac4dac4cc4a8c7b254c.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Linear and Nonlinear Free Vibration of a Two-Dimensional Multiferroic Composite Plate Subjected to Magneto-Electro-Thermo-Aerodynamic Loading
S
Razavi
H
Ghashochi Bargh
Vibration response of a two-dimensional magneto-electro-elastic plate is investigated in this paper. The considered multi-phase plate is rectangular and simply-supported resting on an elastic foundation. The plate is under aerodynamic pressure and subjected to temperature change. It is also assumed that the magneto-electro-elastic body is poled along the z direction and subjected to electric and magnetic potentials between the upper and lower surfaces. The nonlinear vibrational analysis of the described plate is considered as an innovation of the present paper, which had not been done before. To model this problem, third-order shear deformation theory along with Gauss’s laws for electrostatics and magnetostatics, first-order piston theory, and Galerkin and multiple times scale methods are used. After validating the presented method, effects of several parameters on the natural frequency, time history, backbone curve, and phase plane diagram of this smart composite plate are obtained. It is found that for plates with constant a/h ratio, electric and magnetic potentials have noticeable effects on the time histories, phase plane diagrams and backbone curves of the plates with smaller thicknesses. In addition, the numerical results of this research indicate that some parameters have considerable effect on the vibration behavior of presented plate. Elastic parameters of the foundation, applied electric and magnetic potentials, and environment temperature are important parameters in this analysis.
Magneto-electro-elastic
Two-dimensional plate
Third-order plate theory
Nonlinear vibration
Aerodynamic loading
2021
06
30
144
163
http://jsm.iau-arak.ac.ir/article_682341_5c9b07f0b69e6a3943ca49b4f13ef7dd.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Size-Dependent Vibration Problem of Two Vertically-Aligned Single-Walled Boron Nitride Nanotubes Conveying Fluid in Thermal Environment Via Nonlocal Strain Gradient Shell Model
P
Roodgar Saffari
M
Fakhraie
M. A
Roudbari
The free vibration behavior of two fluid-conveying vertically-aligned single-walled boron nitride nanotubes are studied in the present paper via the nonlocal strain gradient piezoelectric theory in conjunction with the first-order shear deformation shell assumption in thermal environments. It is supposed that the two adjacent boron nitride nanotubes are coupled with each other in the context of linear deformation by van der Waals interaction according to Lennard–Jones potential function. To achieve a more accurate modeling for low-scale structures, both hardening and softening effects of materials are considered in the nonlocal strain gradient approach. The motion equations and associated boundary conditions are derived by means of Hamilton’s variational principle, then solved utilizing differential quadrature method. Numerical studies are done to reveal the effect of different boundary conditions, size scale parameters, aspect ratio, inter-tube distance, and temperature change on the variations of dimensionless eigenfrequency and critical flow velocity.
Nonlocal strain gradient
Fluid-conveying boron nitride nanotube
Free vibration
Piezoelectric cylindrical shell
Thermal environment
2021
06
30
164
185
http://jsm.iau-arak.ac.ir/article_682264_c763a35791122338530343da6637fe24.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Response of Two-Temperature on the Energy Ratios at Elastic-Piezothermoelastic Interface
R
Kumar
P
Sharma
In the present investigation the reflection and transmission phenomenon of plane waves between two half spaces elastic and orthotropic piezothermoelastic with two-temperature theory is discussed. A piezothermoelastic solid half space is assumed to be loaded with an elastic half space. Due to the phenomenon, four qausi waves are obtained; quasi longitudinal (qP) wave, quasi transverse (qS) wave, quasi thermal (qT) wave and electric potential wave (eP). It is found that the amplitude ratios of various reﬂected and refracted waves are functions of angle of incidence, frequency of incident wave and are inﬂuenced by the piezothermoelastic properties of media. The energy ratios are computed numerically using amplitude ratios for a particular model of graphite and cadmium selenide (CdSe). The variations of energy ratios with angle of incidence are shown graphically depicting the effect of two-temperature. The conservation of energy across the interface is justiﬁed. A particular case of interest is also deduced from the present investigation.
Reflection
Piezothermoelastic
Energy ratios
Transmission
Orthotropic
Amplitude ratios
2021
06
30
186
201
http://jsm.iau-arak.ac.ir/article_682387_3294c17e11bcc842feaa5ccbb301bd1d.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Photothermoelastic Investigation of Semiconductor Material Due to Distributed Loads
N
Sharma
R
Kumar
A dynamic mathematical model of photothermoelastic (semiconductor) medium is developed to analyze the deformation due to inclined loads. The governing equations for photothermoelastic with dual phase lag model are framed for two dimensional case and are further simplified by using potential function. Appropriate transforms w.r.t time (Laplace) and w.r.t space variables (Fourier) are employed on the resulting equations which convert the system of equations into differential equation. The problem is examined by deploying suitable mechanical boundary conditions. Specific types of distributed loads as uniformly distributed force and Linearly distributed force are taken to examine the utility of the model. The analytic expressions like displacements, stresses, temperature distribution and carrier density are obtained in the new domain (transformed).To recover the quantities in the physical domain, numerical inversion technique is employed. Numerical computed results with different angle of inclination vs distance are analyzed with and without dual phase lag theories of thermoelasticity in the form of visual representations. It is seen that physical field quantities are sensitive towards photothermoelastic and phase lag parameters.
Photo-thermal
semiconductor
Inclined load
Laplace and Fourier transforms
2021
06
30
202
212
http://jsm.iau-arak.ac.ir/article_683153_21c5cdf9f37d4d9af475808798d01634.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Analysis of Nanoplate with a Central Crack Under Distributed Transverse Load Based on Modified Nonlocal Elasticity Theory
M
Rajabi
H
Lexian
A
Rajabi
In this paper, using the complete modified nonlocal elasticity theory, the deflection and strain energy equations of rectangular nanoplates, with a central crack, under distributed transverse load were overwritten. First, the deflection of nanoplate was obtained using Levy's solution and consuming it; strain energy of nanoplate was found. As regards nonlocal elasticity theory wasn’t qualified for predicting the static behavior of nanoplates under distributed transverse load, using modified nonlocal elasticity theory, the deflection of nanoplate with a central crack for different values of the small-scale effect parameter was achieved. It was gained with the convergence condition for the complete modified nonlocal elasticity theory. To verify the result, the results for the state of the small-scale effect parameter were placed equal to zero (plate with macro-scale) and then were compared with the numerical results as well as the classical analytical solution results available in the valid references. It was shown that the complete modified nonlocal elasticity theory does not show any singularity at the crack-tip unlike the classical theory; therefore, the method presented is a suitable method for analysis of the nanoplates with a central crack.
Nonlocal elasticity theory
Crack
Small-scale effect
Nanoplate
Singularity
2021
06
30
213
232
http://jsm.iau-arak.ac.ir/article_683156_f5553143e33f4a3d392e8da479d989b2.pdf
Journal of Solid Mechanics
JSM
2008-3505
2008-3505
2021
13
2
Isogeometric Analysis for Topology Optimisation of Two Dimensional Planar and Laminated Composite Plate Continuum Structures
K.N.V
Chandrasekhar
V
Bhikshma
N
Rakesh
N
Swapnareddy
C
Rakesh
Isogeometric analysis is the recent development in the field of engineering analysis with high performance computing and greater precision. This current research has opened a new door in the field of structural optimisation. The main focus of this research study is to perform topology optimisation of continuum structures in civil engineering using Isogeometric analysis. The continuum structures analysed here in this study are reinforced concrete, steel and laminated composite plates. Reinforced concrete is a rational union of concrete and steel. Topology optimisation of reinforced concrete structures is an emerging area of study to determine the optimal layout of material in the concrete domain. Laminated structures are made of several layers of material and bonded to achieve high stiffness and low weight to strength ratio. The deformed shape at the optimal state can be determined with topology optimisation of laminated composites. The formulation for composite plates is done using kirchoff thin plate theory without any shear contribution. B-splines are used to model the geometry. The objective is to optimise the energy of the structure and optimality criteria is used to calculate the newer values of relative densities. First order sensitivity analysis is performed to determine the newer values of objective function. The code is written in MatLab® and a few problems have been solved with different domains. The results are verified and have shown a good agreement with those in the literature.
Reinforced Concrete
Isogeometric
Topology
Optimisation
Laminates
2021
06
30
233
268
http://jsm.iau-arak.ac.ir/article_682224_1d7ac66a4c953c121e7a134013632507.pdf