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thermal-expansion
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Application of a Thermo-Plastic Constitutive Model for Coupled THM Analysis of Behavior of Saturated Soils
, M.Sc. Thesis Sharif University of Technology ; Pak, Ali (Supervisor)
Abstract
Effects of temperature on the behavior of soils and rocks have been studied widely in recent years. Following the need for understanding the effects of temperature on the behavior of clayey soils, several experimental and numerical studies on thermo-mechanical behavior of clayey soils have been carried out and a number of thermo-mechanical constitutive models have been developed for saturated and unsaturated clayey soils. In this research, a two-yield surface thermo-plastic constitutive model developed by Abuel-Naga et al. (2007, 2009), has been chosen for THM analysis of the behavior of saturated clayey soils. This constitutive model is based on Modified Cam-Clay (MCC) model. The MCC model...
Performance of Unbonded Post-Tensioned Concrete Slab Subjected to Temperature Variations
, M.Sc. Thesis Sharif University of Technology ; Kazemi, Mohammad Taghi (Supervisor)
Abstract
Tests have shown that concrete post-tensioned slab under heat condition suffer a significant reduction in stiffness and strength. Design and implementation of post-tensioned concrete slabs with large spans of industrial structures exposed to extreme variation in temperature can be possible with detailed research on its behavior under heating condition. In this study numerical modelling of PT concrete slabs with unbonded tendons under heating condition was created based on available test results in the literature. A parametric study has been carried out and the results are presented for concrete coefficient thermal expansion, thermal contact conductance between the concrete and the cables,...
Characterization of nanocrystalline CuCo2 O4 spinel prepared by sol–gel technique applicable to the SOFC interconnect coating
,
Article
Applied Physics A: Materials Science and Processing
;
Volume 119, Issue 2
,
May
,
2015
,
Pages 727-734
;
09478396 (ISSN)
; Askari, M
; Ghorbanzadeh, M
;
Sharif University of Technology
Springer Verlag
2015
Abstract
CuCo2 O4 spinel nanopowders were synthesized by sol–gel method. The optimal values of pH and molar ratio of citric acid to metal ions (RC), and the influence of the calcination temperature and time were investigated. As-prepared materials were characterized by XRD, TGA, DSC, FE-SEM and electrical and coefficient of thermal expansion (CTE) measurements. It was found that pH = 4.5 and RC = 1 are the optimum conditions to produce pure CuCo2 O4 nanopowders. The electrical conductivity was increased remarkably from 15.2 to 27.5 S cm−1 with an increase in temperature from 500 to 800 °C. Over the temperature range of 25–800 °C, the CTE of...
Stress analysis of multilayer thin walled pipes with circular cut-outs
, Article World Congress on Engineering 2016, WCE 2016, 29 June 2016 through 1 July 2016 ; Volume 2224 , 2016 , Pages 1146-1150 ; 20780958 (ISSN); 9789881404800 (ISBN) ; Bull, J.W ; Chizari, M ; Ao S.I ; Ao S.I ; Gelman L ; Ao S.I ; Gelman L ; Hukins D.W.L ; Hunter A ; Korsunsky A.M ; et al.; IAENG Society of Artificial Intelligence; IAENG Society of Bioinformatics; IAENG Society of Computer Science; IAENG Society of Data Mining; IAENG Society of Electrical Engineering ; Sharif University of Technology
Newswood Limited
2016
Abstract
A finite element analysis of a double layered shell with a circular hole is carried out with the computer aided engineering software Abaqus (Dassault Systèmes, FR). The model proposed has been used to perform a stress analysis on three pipes with different sized hole. Moreover, thermal expansion has been implemented in the testing. For the purpose of the research, the elastic properties of the materials have been considered and the results compared with the ones previously published in literature. The outcome of the investigation will benefit towards the design of optimal and sustainable pipes with circular cut outs
Thermal buckling responses of a graphene reinforced composite micropanel structure
, Article International Journal of Applied Mechanics ; Volume 12, Issue 1 , 2020 ; Aliakbarlou, H ; Jebeli, M ; Noormohammadiarani, O ; Habibi, M ; Safarpour, H ; Foong, L. K ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2020
Abstract
This is the first research on the thermal buckling analysis of graphene nanoplatelets reinforced composite (GPLRC) doubly curved open cylindrical micropanel in the framework of numerical-based two-dimensional generalized differential quadrature method (2D-GDQM). Additionally, the small-scale effects are analyzed based on nonlocal strain gradient theory (NSGT). The stresses and strains are obtained using the high-order shear deformable theory (HOSDT). The rule of mixture is employed to obtain varying thermal expansion, and Poisson's ratio, while module of elasticity is computed by modified Halpin-Tsai model. In addition, nonlinear temperature changes along the GPLRC micropanel's thickness...
Effect of rubber particle cavitation on the mechanical properties and deformation behavior of high-impact polystyrene
, Article Journal of Applied Polymer Science ; Volume 104, Issue 2 , 2007 , Pages 1110-1117 ; 00218995 (ISSN) ; Zokaei, S ; Bagheri, R ; Sharif University of Technology
2007
Abstract
Rubber particle cavitation has been the focus of many investigations because it dramatically affects the mechanical properties of polymeric blends. In this work, the effect of rubber particle cavitation on the mechanical behavior of high-impact polystyrene was studied. The extent of cavitation in rubber particles was varied via different thermal contraction/expansion cycles in the range of -100 to 23°C. Tensile, creep, and Charpy impact tests were conducted to evaluate the effects of the degree of cavitation on the general mechanical properties. The notch-tip damage zone and deformation micromechanisms were also investigated by a transmitted optical microscopy technique to reveal the effects...
The critical voltage of a GPL-reinforced composite microdisk covered with piezoelectric layer
, Article Engineering with Computers ; Volume 37, Issue 4 , 2021 , Pages 3489-3508 ; 01770667 (ISSN) ; Ebrahimi, F ; Elianddy Bin Supeni, E ; Habibi, M ; Safarpour, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this research, electrically characteristics of a graphene nanoplatelet (GPL)-reinforced composite (GPLRC) microdisk are explored using generalized differential quadrature method. Also, the current microstructure is coupled with a piezoelectric actuator (PIAC). The extended form of Halpin–Tsai micromechanics is used to acquire the elasticity of the structure, whereas the variation of thermal expansion, Poisson’s ratio, and density through the thickness direction is determined by the rule of mixtures. Hamilton’s principle is implemented to establish governing equations and associated boundary conditions of the GPLRC microdisk joint with PIAC. The compatibility conditions are satisfied by...
Temperature and thickness effects on thermal and mechanical stresses of rotating FG-disks
, Article Journal of Mechanical Science and Technology ; Volume 25, Issue 3 , 2011 , Pages 827-836 ; 1738494X (ISSN) ; Azadi, M ; Sharif University of Technology
Abstract
In the present paper, radial and hoop thermal and mechanical stress analysis of a rotating disk made of functionally graded material (FGM) with variable thickness is carried out by using finite element method (FEM). To model the disk by FEM, one-dimensional two-degree elements with three nodes are used. It is assumed that the material properties, such as elastic modulus, Poisson's ratio and thermal expansion coefficient, are considered to vary using a power law function in the radial direction. The geometrical and boundary conditions are in the shape of two models including thermal stress (model-A) and mechanical stress (model-B). In model-A there exists no pressure in both external and...
Nonlinear thermoelastic stress analysis of the rotating FGM disk with variable thickness and temperature-dependent material properties using finite element method
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings, 13 November 2009 through 19 November 2009 ; Volume 14 , 2010 , Pages 359-364 ; 9780791843871 (ISBN) ; Damircheli, M ; Sharif University of Technology
Abstract
In this paper, nonlinear radial and hoop thermoelastic stress analysis of rotating disk made of functionally graded material (FGM) with variable thickness is carried out by using the finite element method. In this method, one-dimensional second order elements with three nodes have been used. The geometrical and boundary conditions are in the shape of nonexistence of the pressure (zero radial stress) in both external and internal layers and zero displacement at the internal layer of rotating disk. Furthermore, it's assumed that heat distribution is as second order curve while material properties such as elasticity modulus, Poisson's ratio and thermal expansion coefficient vary by using a...
Thermal residual stresses in silicon thin film solar cells under operational cyclic thermal loading: A finite element analysis
, Article Solar Energy ; Volume 135 , 2016 , Pages 366-373 ; 0038092X (ISSN) ; Dehghany, M ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
In manufacturing amorphous silicon solar cells, thin films are deposited at high temperatures (200-400 °C) on a thick substrate using sputtering and plasma enhanced chemical vapor deposition (PECVD) methods. Since the thin films and substrate have different thermal expansion coefficients, cooling the system from deposition temperature to room temperature induces thermal residual stresses in both the films and substrate. In addition, these stresses, especially those having been induced in the amorphous silicon layer can change the carrier mobility and band gap energy of the silicon and consequently affect the solar cell efficiency. In this paper, a 2D finite element model is proposed to...
Investigation on the characteristics of micro- and nano-structured W-15 wt.%Cu composites prepared by powder metallurgy route
, Article International Journal of Refractory Metals and Hard Materials ; Volume 30, Issue 1 , 2012 , Pages 145-151 ; 02634368 (ISSN) ; Masoudi, A ; Safabinesh, H ; Takestani, M ; Sharif University of Technology
2012
Abstract
The properties of W-15 wt.%Cu composites were investigated by preparing two distinct composites of micrometer and nanoscale structures. Micrometer composite was produced by mixing elemental W and Cu powders and nanometer one was synthesized through a mechanochemical reaction between WO3 and CuO powders. Subsequent compaction and sintering process was performed to ensure maximum possible densification at 1000-1200 °C temperatures. Finally, the behavior of produced samples including relative density, hardness, compressive strength, electrical conductivity, coefficient of thermal expansion (CTE) and room temperature corrosion resistance were examined. Among the composites, nano-structured...
Calculation of thermodynamic properties of Ni nanoclusters via selected equations of state based on molecular dynamics simulations
, Article Solid State Communications ; Volume 151, Issue 14-15 , 2011 , Pages 965-970 ; 00381098 (ISSN) ; Abroshan, H ; Taherkhani, F ; Parsafar, G. A ; Sharif University of Technology
2011
Abstract
We present an approach for constant-pressure molecular dynamics simulations. This approach is especially designed for finite systems, for which no periodic boundary condition applies. A molecular dynamics (MD) simulation for Ni nanoclusters is used to calculate their pressurevolumetemperature (pvT) data for the temperature range 200 K≤T≤400 K, and pressures up to 600 kbar. Isothermal sets of pvT data were generated by the simulation; each set was fitted by three equations of state (EoSs): Linear Isotherm Regularity-II (LIRII), BirchMurnaghan (BM), and EOS III. It is found that the MD data are satisfactorily reproduced by the EoSs with reasonable precision. Some features of the EoSs criteria,...
Novel manufacturing process of nanoparticle/Al composite filler metals of tungsten inert gas welding by accumulative roll bonding
, Article Materials Science and Engineering A ; Volume 648 , 2015 , Pages 47-50 ; 09215093 (ISSN) ; Noei Aghaei, V ; Dabiri, A. R ; Amirkhanlou, S ; Akhavan, S ; Fattahi, Y ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
In the present work, accumulative roll bonding (ARB) was used as an effective method for manufacturing nanoparticle/Al composite filler metals of tungsten inert gas (TIG) welding. After welding, the distribution of ceramic nanoparticles and mechanical properties of welds were investigated. By applying ARB, ceramic nanoparticles were uniformly dispersed in the composite filler metals. Consequently, the welds produced by these filler metals had a uniform dispersion of ceramic nanoparticles in their compositions. The test results showed that the yield strength of welds was greatly increased when using the nanoparticle/Al composite filler metals. The improvement in the yield strength was...
Thermal stresses and kinetics of phase transformation on the run-out table after hot strip rolling of low-carbon steels
, Article International Journal of Advanced Manufacturing Technology ; Volume 83, Issue 9-12 , 2016 , Pages 1725-1736 ; 02683768 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
Abstract
A thermo-elastic analysis coupled with a phase change model is employed to evaluate thermal stresses as well as progress of austenite decomposition after hot strip rolling operations. The thermo-mechanical finite element analysis is utilized to assess the distributions of temperature and thermal stresses during cooling while at the same time, a model based on the additivity rule is used to determine the rate of austenite to ferrite decomposition. The proposed model is applicable to multi-pass rolling schedules while the effects of different process parameters including the rolling speed and cooling configuration of the run-out table can be taken into account. In order to verify the...
Relief of edge effects in bi-adhesive composite joints
, Article Composites Part B: Engineering ; Volume 108 , 2017 , Pages 153-163 ; 13598368 (ISSN) ; Tahani, M ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Three-dimensional thermo-mechanical stress analysis of composite joints with bi-adhesive bonding is presented using the full layerwise theory. Based on three-dimensional elasticity theory, sets of fully coupled governing differential equations are derived using the principle of minimum total potential energy and are simultaneously solved using the state space approach. Results show that bi-adhesive bonding substantially relieves the edge effects. Moreover, series of parametric studies reveal the nonlinear effects of bonding length ratio and the relative stiffness and coefficient of thermal expansion of the mid- and side-adhesives. It is also concluded that the optimum design of a bi-adhesive...
Oxidized graphitic carbon nitride nanosheets as an effective adsorbent for organic dyes and tetracycline for water remediation
, Article Journal of Alloys and Compounds ; Volume 809 , 2019 ; 09258388 (ISSN) ; Villar Rodil, S ; Paredes, J. I ; Zaker Moshfegh, A. R ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Graphitic carbon nitride (g-C3N4) is promising as adsorbent for water remediation as its chemical structure allows a variety of mechanisms to interact with wastewater pollutants. However, several issues, such as low specific surface area and insufficient dispersibility in water, have to be tackled to achieve a competitive performance in such use. Previous attempts to improve the features of g-C3N4as an adsorbent have relied on carbon doping and exfoliation in the solid phase by thermal expansion. Here, we demonstrate that exfoliation in the liquid phase by a combination of oxidation and sonication allows preparing g–C3N4–based materials with improved dispersibility in water, increased...
Critical voltage, thermal buckling and frequency characteristics of a thermally affected GPL reinforced composite microdisk covered with piezoelectric actuator
, Article Mechanics Based Design of Structures and Machines ; 2020 ; Ghabussi, A ; Forooghi, A ; Shavalipour, A ; Habibi, M ; won Jung, D ; Safa, M ; Sharif University of Technology
Taylor and Francis Inc
2020
Abstract
Due to the remarkable progress in the field of the manufacturing process, smart composites have become the desired target for high-tech engineering applications. Accordingly, for the first time, thermal buckling, critical voltage and vibration response of a thermally affected graphene nanoplatelet reinforced composite (GPLRC) microdisk in the thermal environment are explored with the aid of generalized differential quadrature method (GDQM). Also, the current microstructure is coupled with a piezoelectric actuator (PIAC). The extended form of Halpin-Tsai micromechanics is used to acquire the elasticity of the structure, whereas, the variation of thermal expansion, Poisson’s ratio, and density...
The critical voltage of a GPL-reinforced composite microdisk covered with piezoelectric layer
, Article Engineering with Computers ; 2020 ; Ebrahimi, F ; Elianddy Bin Supeni, E ; Habibi, M ; Safarpour, H ; Sharif University of Technology
Springer
2020
Abstract
In this research, electrically characteristics of a graphene nanoplatelet (GPL)-reinforced composite (GPLRC) microdisk are explored using generalized differential quadrature method. Also, the current microstructure is coupled with a piezoelectric actuator (PIAC). The extended form of Halpin–Tsai micromechanics is used to acquire the elasticity of the structure, whereas the variation of thermal expansion, Poisson’s ratio, and density through the thickness direction is determined by the rule of mixtures. Hamilton’s principle is implemented to establish governing equations and associated boundary conditions of the GPLRC microdisk joint with PIAC. The compatibility conditions are satisfied by...
Using molecular dynamic simulation data of calcite in a wide pressure range to calculate some of its thermodynamic properties via some universal equations of state
, Article Molecular Physics ; Volume 106, Issue 21-23 , 2008 , Pages 2545-2556 ; 00268976 (ISSN) ; Shokouhi, M ; Parsafar, G. A ; Sharif University of Technology
2008
Abstract
Molecular dynamics, MD, simulation of calcite (CaCO3) is selected to compare the p-v-T behaviour of some universal equations of state, UEOS, for the temperature range 100 K ≤ T 800 ≤ K, and pressures up to 3000 kbar. The isothermal sets of p-v-T data generated by simulation were each fitted onto some three- and two-parameter EOSs including Parsafar and Mason (PM), Linear Isotherm Regularity (LIR), Birch-Murnaghan (BM), Shanker, Vinet, Baonza and Modified generalized Lennard-Jones (MGLJ) EOSs. It is found that the MD data satisfactorily fit these UEOS with reasonable precision. Some features for a good UEOS criteria such as temperature dependencies of coefficients, pressure deviation,...
Critical voltage, thermal buckling and frequency characteristics of a thermally affected GPL reinforced composite microdisk covered with piezoelectric actuator
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 4 , 2022 , Pages 1331-1353 ; 15397734 (ISSN) ; Ghabussi, A ; Forooghi, A ; Shavalipour, A ; Habibi, M ; won Jung, D ; Safa, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Due to the remarkable progress in the field of the manufacturing process, smart composites have become the desired target for high-tech engineering applications. Accordingly, for the first time, thermal buckling, critical voltage and vibration response of a thermally affected graphene nanoplatelet reinforced composite (GPLRC) microdisk in the thermal environment are explored with the aid of generalized differential quadrature method (GDQM). Also, the current microstructure is coupled with a piezoelectric actuator (PIAC). The extended form of Halpin-Tsai micromechanics is used to acquire the elasticity of the structure, whereas, the variation of thermal expansion, Poisson’s ratio, and density...