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RISS 인기검색어
- 검색키워드
- 저자 : Amir Behshad (검색결과 6 건)
- 무료
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- 유료
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Elastic wave propagation analysis in sandwich nanoplate assuming size effects
Amir Behshad,Maryam Shokravi,Akbar Shafiei Alavijeh,Hamed Karami 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.47 No.1
This paper presents a study on the wave propagation of functionally graded material (FGM) sandwich nanoplates with soft core resting on a Winkler foundation. The structure is modelled by classical theory. Motion equations are derived by the assumption of nonlocal Eringen theory and energy method. Then, the equations are solved using an exact method for finding phase velocity responses. The effects of Winkler foundation, nonlocal parameters, thickness and mode number on the dispersion of elastic waves are shown. With the increase of spring constant, the speed of wave propagation increases and reaches a uniform state at a higher wave number.
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Electro-thermo-mechanical stress analysis of smart sandwich cylindrical shell
Yuhua Zhou,Mohamed Amine Khadimallah,Seyedmahmoodreza Allahyari,Amir behshad 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.40 No.5
In this paper, stress analysis of a multi-walled hollow cylinder made from a functionally graded material (POLYMER) sandwiched between two piezoelectric layers is investigated. This system is subjected to internal and external pressure, a distributed temperature field due to steady state heat conduction with convective boundary condition, and a constant potential difference imposed on piezoelectric layers between its inner and outer surfaces or combination of these loadings. All mechanical and thermal properties except for the Poisson’s ratio of Polymer layer are assumed to be power functions of the radial position. Using equilibrium equations, stress-strain relations and electromechanical coupling of piezoelectric layer, the constitutive differential equation in term of radial displacement is obtained. Considering electro-mechanical boundary conditions, this differential equation is analytically solved. The electro-thermo-mechanical stresses, electric potential and radial displacement distributions in three layers are obtained.
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Numerical simulation of the flow in pipes with numerical models
Hongjie Gao,Xinyu Li,Abdolreza Hooshmandi Nezhad,Amir Behshad 국제구조공학회 2022 Structural Engineering and Mechanics, An Int'l Jou Vol.81 No.4
The objective of this study is to simulate the flow in pipes with various boundary conditions. Free-pressure fluid model, is used in the pipe based on Navier-Stokes equation. The models are solved by using the numerical method. A problem called “stability of pipes” is used in order to compare frequency and critical fluid velocity. When the initial conditions of problem satisfied the instability conditions, the free-pressure model could accurately predict discontinuities in the solution field. Employing nonlinear strains-displacements, stress-strain energy method the governing equations were derived using Hamilton's principal. Differential quadrature method (DQM) is used for obtaining the frequency and critical fluid velocity. The results of this paper are analyzed by hyperbolic numerical method. Results show that the level of numerical diffusion in the solution field and the range of well-posedness are two important criteria for selecting the two-fluid models. The solutions for predicting the flow variables is approximately equal to the two-pressure model 2. Therefore, the predicted pressure changes profile in the twopressure model is more consistent with actual physics. Therefore, in numerical modeling of gas-liquid two-phase flows in the vertical pipe, the present model can be applied.
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Suxia Hou,Shengbin Wu,Jijun Luo,Mohsen Nasihatgozar,Amir Behshad 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.45 No.4
Improving the mechanical properties of concrete in the construction industry in order to increase resistance to dynamic and static loads is one of the essential topics for researchers. In this work, vibration analysis of elastic nanocomposite beams reinforced by nanoparticles based on mathematical model is presented. For modelling of the strucuture, sinusoidal shear deformation beam theory (SSDBT) is utilized. Mori-anak model model is utilized for obtaining the effective properties of the strucuture including agglomeration influences. Utilizing the energy method and Hamilton’s principal, the motion equations are calculated. The frequency of the elastic nanocomposite beam is obtanied by analytical method. The aim of this work is investigating the effects of nanoparticles volume percent and agglomeration, length and thickness of the beam on the frequency of the structure. The results show that the with enhancing the nanoparticles volume percent, the frequency is increased. In addition, the water absorption of the concrete is presented in this article.
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Luo, Jijun,Lv, Meng,Hou, Suxia,Nasihatgozar, Mohsen,Behshad, Amir Techno-Press 2022 Advances in nano research Vol.13 No.4
Dynamic study of concrete plates under impact load is presented in this article. The main objective of this work is presenting a mathematical model for the concrete plates under the impact load. The concrete plate is reinforced by carbon nanoparticles which the effective material proprieties are obtained by mixture's rule. Impacts are assumed to occur normally over the top layer of the plate and the interaction between the impactor and the structure is simulated using a new equivalent three-degree-of-freedom (TDOF) spring-mass-damper (SMD) model. The structure is assumed viscoelastic based on Kelvin-Voigt model. Based on the classical plate theory (CPT), energy method and Hamilton's principle, the motion equations are derived. Applying DQM, the dynamic deflection and contact force of the structure are calculated numerically so that the effects of mass, velocity and height of the impactor, volume percent of nanoparticles, structural damping and geometrical parameters of structure are shown on the dynamic deflection and contact force. Results show that considering structural damping leads to lower dynamic deflection and contact force. In addition, increasing the volume percent of nanoparticles yields to decreases in the deflection.
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Investigation of hyperbolic dynamic response in concrete pipes with two-phase flow
Zheng, Chuanzhang,Yan, Gongxing,Khadimallah, Mohamed Amiine,Nouri, Alireza Zamani,Behshad, Amir Techno-Press 2022 Advances in concrete construction Vol.13 No.5
The objective of this study is to simulate the two-phase flow in pipes with various two-fluid models and determinate the shear stress. A hyperbolic shear deformation theory is used for modelling of the pipe. Two-fluid models are solved by using the conservative shock capturing method. Energy relations are used for deriving the motion equations. When the initial conditions of problem satisfied the Kelvin Helmholtz instability conditions, the free-pressure two-fluid model could accurately predict discontinuities in the solution field. A numerical solution is applied for computing the shear stress. The two-pressure two-fluid model produces more numerical diffusion compared to the free-pressure two-fluid and single-pressure two-fluid models. Results show that with increasing the two-phase percent, the shear stress is reduced.
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