A nonlocal nonlinear analysis for buckling in embedded FG-SWCNT-reinforced microplates subjected to magnetic field

Reza Kolahchi,Mahmood Rabani Bidgoli,Gholamhossein Beygipoor,Mohammad Hosein Fakhar 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.9

In this study, nonlocal nonlinear buckling analysis of embedded polymeric temperature-dependent microplates resting on an elasticmatrix as orthotropic temperature-dependent elastomeric medium is investigated. The microplate is reinforced by single-walled carbonnanotubes (SWCNTs) in which the equivalent material properties of nanocomposite are estimated based on the rule of mixture. Due tomagnetic properties of SWCNTs, the structure is subjected to magnetic field. For the carbon-nanotube reinforced composite (CNTRC)plate, both cases of uniform distribution (UD) and functionally graded (FG) distribution patterns of SWCNT reinforcements are considered. The small size effects of microplate are considered based on Eringen’s nonlocal theory. Based on orthotropic Mindlin plate theoryalong with von Kármán geometric nonlinearity and Hamilton's principle, the governing equations are derived. Generalized differentialquadrature method (GDQM) is applied for obtaining the buckling load of system. The effects of different parameters such as magneticfield, nonlocal parameters, volume fractions of SWCNTs, distribution type of SWCNTs in polymer, elastomeric medium, aspect ratioand temperature are considered on the nonlinear buckling of the microplate. Results indicate that the buckling load increases with increasingmagnetic field.

Size-dependent bending analysis of FGM nano-sinusoidal plates resting on orthotropic elastic medium

Reza Kolahchi,Ali Mohammad Moniri Bidgoli,Mohammad Mehdi Heydari 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.5

Bending analysis of functionally graded (FG) nano-plates is investigated in the present work based on a new sinusoidal shear deformation theory. The theory accounts for sinusoidal distribution of transverse shear stress, and satisfies the free transverse shear stress conditions on the top and bottom surfaces of the plate without using shear correction factor. The material properties of nano-plate are assumed to vary according to power law distribution of the volume fraction of the constituents. The size effects are considered based on Eringen's nonlocal theory. Governing equations are derived using energy method and Hamilton’s principle. The closed-form solutions of simply supported nano-plates are obtained and the results are compared with those of first-order shear deformation theory and higher-order shear deformation theory. The effects of different parameters such as nano-plate length and thickness, elastic foundation, orientation of foundation orthtotropy direction and nonlocal parameters are shown in dimensionless displacement of system. It can be found that with increasing nonlocal parameter, the dimensionless displacement of nanoplate increases.

Experimental study for ZnO nanofibers effect on the smart and mechanical properties of concrete

Reza Kolahchi,Amir Arbabi,Mahmood Rabani Bidgoli 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.1

Due to the superior properties of nanoparticles, using them has been increased in concrete production technology. In this study, the effect of zinc oxide (ZnO) nanoparticles on the mechanical and smart properties of concrete was studied. At the first, the ZnO nanoparticles are dispersed in water using shaker, magnetic stirrer and ultrasonic devices. The nanoparticles with 3.5, 0.25, 0.75, and 1.0 volume percent are added to the concrete mixture and replaced by the appropriate amount of cement to compare with the control sample without any additives. In order to study the mechanical and smart properties of the concrete, the cubic samples for determining the compressive strength and cylindrical samples for determining tensile strength with different amounts of ZnO nanoparticles are produced and tested. The most important finding of this paper is about the smartness of the concrete due to the piezoelectric properties of the ZnO nanoparticles. In other words, the concrete in this study can produce the voltage when subjected to mechanical load and vice versa it can induce the mechanical displacement when subjected to external voltage. The experimental results show that the best volume percent for ZnO nanoparticles in 28-day samples is 0.5%. In other words, adding 0.5% ZnO nanoparticles to the concrete instead of cement leads to increases of 18.70% and 3.77% in the compressive and tensile strengths, respectively. In addition, it shows the best direct and reverse piezoelectric properties. It is also worth to mention that adding 3.5% zinc oxide nanoparticles, the setting of cement is stopped in the concrete mixture.

Agglomeration effects on the buckling behaviour of embedded concrete columns reinforced with SiO₂ nano-particles

Zamanian, Mohammad,Kolahchi, Reza,Bidgoli, Mahmood Rabani Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.1

The use of nanotechnology materials and applications in the construction industry should be considered for enhancing material properties. However, the nonlinear buckling of an embedded straight concrete columns reinforced with silicon dioxide ($SiO_2$) nanoparticles is investigated in the present study. The column is simulated mathematically with Euler-Bernoulli and Timoshenko beam models. Agglomeration effects and the characteristics of the equivalent composite are determined using Mori-Tanaka approach. The foundation around the column is simulated with spring and shear layer. The governing equations are derived using energy method and Hamilton's principal. Differential quadrature method (DQM) is used in order to obtain the buckling load of structure. The influences of volume percent of $SiO_2$ nanoparticles, geometrical parameters and agglomeration on the buckling of column are investigated. Numerical results indicate that considering agglomeration effects leads to decrease in buckling load of structure.

Dynamic analysis of concrete column reinforced with Sio₂ nanoparticles subjected to blast load

Azmi, Masoud,Kolahchi, Reza,Bidgoli, Mahmood Rabani Techno-Press 2019 Advances in concrete construction Vol.7 No.1

The project focuses on the dynamic analysis of concrete beams reinforced with silica-nanoparticles under blast loading. The structure is located at two boundary conditions. The equivalent composite properties are determined using Mori-Tanak model. The structure is simulated with sinusoidal shear deformation theory. Employing nonlinear strains-displacements, stress-strain, the energy equations of beam were obtained and using Hamilton's principal, the governing equations were derived. Using differential quadrature methods (DQM) and Newmark method, the dynamic deflection of the structure is obtained. The influences of volume percent and agglomeration of silica nanoparticles, geometrical parameters of beam, boundary condition and blast load on the dynamic deflection were investigated. Results showed that with increasing volume percent of silica nanoparticles, the dynamic deflection decreases.

Dynamic analysis of concrete beams reinforced with Tio₂ nano particles under earthquake load

Sharifi, Morteza,Kolahchi, Reza,Bidgoli, Mahmood Rabani Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

This research studies the dynamic analysis of a concrete column reinforced with titanium dioxide ($TiO_2$) nanoparticles under earthquake load. The effect of nanoparticles accumulation in a region of concrete column is examined using Mori-Tanaka model. The structure is simulated mathematically based on the theory of sinusoidal shear deformation theory (SSDT). By calculating strain-displacement and stress-strain relations, the system energies include potential energy, kinetic energy, and external works are derived. Then, using the Hamilton's principle, the governing equations for the structure are extracted. Using these equations, the response of the concrete column under earthquake load is investigated using the numerical methods of differential quadrature (DQ) and Newark. The purpose of this study is to study the effects of percentage of nanoparticles, nanoparticles agglomeration, geometric parameters and boundary conditions on the dynamic response of the structure. The results indicate that by increasing the volume percent of $TiO_2$ nanoparticles, the maximum dynamic deflection of the structure decreases.

Concrete columns reinforced with Zinc Oxide nanoparticles subjected to electric field: buckling analysis

Arbabi, Amir,Kolahchi, Reza,Bidgoli, Mahmood Rabani Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.24 No.5

As concrete is most usable material in construction industry it's been required to improve its quality. Nowadays, nanotechnology offers the possibility of great advances in construction. In this study, buckling of horizontal concrete columns reinforced with Zinc Oxide (ZnO) nanoparticles is analyzed. Due to the presence of ZnO nanoparticles which have piezoelectric properties, the structure is subjected to electric field for intelligent control. The Column is located in foundation with vertical springs and shear modulus constants. Sinusoidal shear deformation beam theory (SSDBT) is applied to model the structure mathematically. Micro-electro-mechanic model is utilized for obtaining the equivalent properties of system. Using the nonlinear stress-strain relation, energy method and Hamilton's principal, the motion equations are derived. The buckling load of the column is calculated by Difference quadrature method (DQM). The aim of this study is presenting a mathematical model to obtain the buckling load of structure as well as investigating the effect of nanotechnology and electric filed on the buckling behavior of structure. The results indicate that the negative external voltage applied to the structure, increases the stiffness and the buckling load of column. In addition, reinforcing the structure by ZnO nanoparticles, the buckling load of column is increased.

Vibration and instability analysis of pipes reinforced by SiO2 nanoparticles considering agglomeration effects

Hadi Golabchi,Reza Kolahchi,Mahmood Rabani Bidgoli 사단법인 한국계산역학회 2018 Computers and Concrete, An International Journal Vol.21 No.4

Fluid velocity analysis on the instability of pipes reinforced by silica nanoparticles (SiO2) is presented in this paper. Mori-Tanaka model is used for obtaining the effective materials properties of the nanocomposite structure considering agglomeration effects. The well known Navier-Stokes equation is used for obtaining the applied force of fluid to pipe. Based on the Reddy higher-order shear deformation theory, the motion equations are derived based on energy method and Hamilton’s principal. The frequency and critical fluid velocity of structure are calculated using differential quadrature method (DQM) so that the effects of different parameters such as volume fractions of SiO2 nanoparticles, SiO2 nanoparticles agglomeration, boundary conditions and geometrical parameters of pipes are considered on the nonlinear vibration and instability of the pipe. Results indicate that increasing the volume fractions of SiO2 nanoparticles, the frequency and critical fluid velocity of the structure are increased. Furthermore, considering SiO2 nanoparticles agglomeration, decreases the frequency and critical fluid velocity of the pipe.

Nonlinear viscose flow induced nonlocal vibration and instability of embedded DWCNC via DQM

A. Ghorbanpour Arani,R. Kolahchi,S. Haghighi,A. A. Mosallaie Barzoki 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.1

Nonlinear thermo free vibration and instability of viscose fluid-conveying double-walled carbon nanocones (DWCNCs) are studied using Hamilton’s principle and differential quadrature method (DQM). The small-size effects on bulk viscosity and slip boundary conditions of nanoflow through Knudsen number (Kn) is considered. The nanocone is simulated as a clamped-clamped Euler-Bernoulli's beam embedded in an elastic foundation of the Winkler and Pasternak type. The van der Waals (vdW) forces between the inner and outer nanocones are taken into account. The detailed parametric study is conducted, focusing on the combined effects of the nonlocal parameter, apex angles, aspect ratio, temperature change, fluid viscosity, boundary conditions and the elastic medium coefficient on the dimensionless frequency and critical fluid velocity of DWCNCs. The results show that the small-size effect on flow field is remarkable on frequency and critical fluid velocity of DWCNC. Also, the nonlinear frequency and critical flow velocity decrease with increasing the nonlocal parameter and cone semi-vertex angle. The results are in good agreement with the previous researches.

Dynamic analysis of concrete beams reinforced with Tio2 nano particles under earthquake load

Morteza Sharifi,Reza Kolahchi,Mahmood Rabani Bidgoli 한국풍공학회 2018 Wind and Structures, An International Journal (WAS Vol.26 No.1

This research studies the dynamic analysis of a concrete column reinforced with titanium dioxide (TiO2) nanoparticles under earthquake load. The effect of nanoparticles accumulation in a region of concrete column is examined using Mori-Tanaka model. The structure is simulated mathematically based on the theory of sinusoidal shear deformation theory (SSDT). By calculating strain-displacement and stress-strain relations, the system energies include potential energy, kinetic energy, and external works are derived. Then, using the Hamilton\'s principle, the governing equations for the structure are extracted. Using these equations, the response of the concrete column under earthquake load is investigated using the numerical methods of differential quadrature (DQ) and Newark. The purpose of this study is to study the effects of percentage of nanoparticles, nanoparticles agglomeration, geometric parameters and boundary conditions on the dynamic response of the structure. The results indicate that by increasing the volume percent of TiO2 nanoparticles, the maximum dynamic deflection of the structure decreases.