2020-06-05T13:22:55Z
http://jacm.scu.ac.ir/?_action=export&rf=summon&issue=1643
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Multi-boiling Heat Transfer Analysis of a Convective Straight Fin with Temperature-Dependent Thermal Properties and Internal Heat Generation
Gbeminiyi
Sobamowo
Ola
Kamiyo
In this study, by using the finite volume method, the heat transfer in a convective straight fin with temperature-dependent thermal properties and an internal heat generation under multi-boiling heat transfer modes are analyzed. In this regard, the local heat transfer coefficient is considered to vary within a power-law function of temperature. In the present study, the coexistence of all the boiling modes is taken into consideration. The developed heat transfer models and the corresponding numerical solutions are used to investigate the effects of various thermo-geometric parameters on the thermal performance of the longitudinal rectangular fin. The results shows that the fin temperature distribution, the total heat transfer, and the fin efficiency are significantly affected by the thermo-geometric parameters of the fin and the internal heat generation within the fin. The obtained results can provide a platform for improvements in the design of the fin in the heat transfer equipment.
Multi-boiling heat transfer
Convective straight fin
Finite volume method
Temperature-dependent properties
Internal heat generation
2017
10
01
229
239
http://jacm.scu.ac.ir/article_12637_5df64def27b178be1e7fe495cbc745e2.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Effect of Variable Thermal Expansion Coefficient and Nanofluid Properties on Steady Natural Convection in an Enclosure
Esmaeil
Ghahremani
Reihaneh
Ghaffari
Hossein
Ghadjari
Javad
Mokhtari
Steady state natural convection is numerically investigated in an enclosure using variable thermal conductivity, viscosity and thermal expansion coefficient of Al<sub>2</sub>O<sub>3</sub>–water nanofluid. This study has been conducted for a wide range of Rayleigh numbers (10<sup>3</sup>≤ Ra ≤ 10<sup>6</sup>), concentrations of nanoparticles (0% ≤ Φ ≤ 7%), enclosure aspect ratios (0.5 ≤ AR ≤ 2) and temperature differences between the cold and the hot walls (1≤ ∆T≤ 30). The main idea in this study is about the effect of temperature on natural convection pattern of nanofluid by changing nanoparticles concentration. Also, changing thermal expansion coefficient with temperature is considerd in this study which will have significant effects on natural convection and has not been considerd before. In low Rayleigh numbers (Ra= 10<sup>3</sup>) and for cavities with AR≥1, the pattern shown in the average Nusselt number versus volume fraction of nanoparticles diagram deteriorates by increasing ∆T. However, for other cases, increasing ∆T has a positive effect on Nu-Φ diagram. The actual Nuselt number curve depicts that dispersing nanoparticles in base fluid deteriorate natural convection heat transfer which is in a good agreement with experimental works.
Nanofluid
Natural convection
variable property
2017
10
01
240
250
http://jacm.scu.ac.ir/article_12714_55c5dafae1098d72acb22f407106098c.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Investigation on the Ultrasonic Tube Hydroforming in the Bulging Process Using Finite Element Method
Mehdi
Zarei
Gholam
Faghani
Mahmood
Farzin
Mohammad
Mashayekhi
In ultrasonic tube hydroforming, the tube is hydro formed while the ultrasonic vibration is applied to the die. Prior studies provide experimental proof that ultrasonic tube hydroforming reduces corner radius, improves lubrication and uniform thickness. Use of ultrasonic vibration can decrease friction at the tube-die interface. Few attempts have been made to analyze the wire drawing while the ultrasonic vibrations were also applied during the processes. A detailed analysis and understanding of the mechanism of improvement is not possible with conventional experimental observation because the ultrasonic vibration processing phenomenon occurs at high speed. Therefore, we attempt to understand the processing mechanism of ultrasonic tube hydroforming using the finite element method (FEM).ABAQUS was used for the FEM. Forming force and formability in tube hydroforming analyzed. From these studies, we quantitatively clarified the mechanism of improved formability characteristics, such as decreased forming load and increasing bulging diameter.
tube hydroforming
ultrasonic oscillation
Finite element method
bulging process
2017
10
01
251
257
http://jacm.scu.ac.ir/article_13039_18ebd89164a757f250746d50879867ef.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Flow and Heat Transfer Analysis of the Sodium Alginate Conveying Copper Nanoparticles between Two Parallel Plates
Akin T.
Akinshilo
Joseph O.
Olofinkua
Osamudiamen
Olaye
In this study, the steady incompressible flow of a non-Newtonian sodium alginate (SA) fluid conveying copper nanoparticles (Cu) which flow within two vertical parallel plates is investigated by using the homotopy perturbation analytical scheme to solve the coupled nonlinear ordinary equations arising from the mechanics of the fluid. The developed analytical solutions are used to investigate the effect of the fluid flow and heat transfer parameters such as the nanoparticle concentration, the non-Newtonian parameter and the viscosity variation parameter. The obtained analytical results as compared to existing works in literature are in satisfactory agreements. Moreover, the results obtained from the present study can be used for further analysis of the behavior of the sodium alginate in applications such as food processing and chemical and pharmaceutical industries.
Sodium alginate
Copper
Parallel plates
Perturbation
Nano fluid
Non-Newtonian
2017
10
01
258
266
http://jacm.scu.ac.ir/article_12773_4e9476351be085fb2c60f039426d4c33.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
A Method for Determination of the Fundamental Period of Layered Soil Profiles
Duygu
Ozturk
K. Burak
Bozdogan
In this study, a method is proposed to determine the fundamental period of layered soil profiles. A model considering the layered soil as shear type structure is used. At first, the soil profile is divided into substructures. Then, the stiffness matrices of the substructures considered as the equivalent shear structures are assembled according to the Finite Element Method. Thereinafter, the stiffness matrices of the substructures are transformed into the Modified Finite Element Transfer Matrices, which take part in the literature. Finally, the system matrix is assembled using matrices of the substructures. The proposed method provides reduction in the size of the matrix. Therefore, analysis time is remarkably reduced. At the end of the study, the accuracy of the method is presented by the examples. Consequently, the proposed method offers a practical method for determination of the fundamental period of the soil.
Finite element
Soil profile
fundamental period
Transformation
Transfer matrix
2017
10
01
267
273
http://jacm.scu.ac.ir/article_13034_032bcb82acb6d5cc6f34dc9aaa2cca89.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Bending, Buckling and Vibration of a Functionally Graded Porous Beam Using Finite Elements
Noha
Fouda
Tawfik
El-midany
A. M.
Sadoun
This study presents the effect of porosity on mechanical behaviors of a power distribution functionally graded beam. The Euler-Bernoulli beam is assumed to describe the kinematic relations and constitutive equations. Because of technical problems, particle size shapes and micro-voids are created during the fabrication which should be taken into consideration. Two porosity models are proposed. The first one describes properties in the explicit form as linear functions of the porosity parameter. The second is a modified model which presents porosity and Young’s modulus in an implicit form where the density is assumed as a function of the porosity parameter and Young’s modulus as a ratio of mass with porosity to the mass without porosity. The modified proposed model is more applicable than the first model. The finite element model is developed to solve the problem by using the MATLAB software. Numerical results are presented to show the effects of porosity on mechanical behaviors of functionally graded beams.
Mechanical Behaviors
Porous material
Functionally graded material
Beam Analysis
Finite element method
2017
10
01
274
282
http://jacm.scu.ac.ir/article_12817_a580c4a4f6f4b08d0a2c876ed28fe3ed.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Finite Element Analysis for CFST Columns under Blast Loading
Peyman
Beiranvand
Fereydoon
Omidinasab
Marziye
Sadate Moayeri
Shahpoor
Mehdipour
Mohammad
Zarei
The columns of frame structures are the key load-bearing components and the exterior columns are susceptible to attack in terrorist blasts. When subjected to blast loads, the columns would suffer a loss of bearing capacity to a certain extent due to the damage imparted which may lead to their collapse and even cause the progressive collapse of the whole structure . The concrete-filled steel columns have been extensively used in the world due to the existence of all suitable characteristics of concrete and steel, more ductility, increasing concrete confinement using the steel wall, the large energy-absorption capacity and the appropriate fire behavior. In the present study, the concrete-filled steel square columns have been simulated under the influence of the blast load using the ABAQUS software. These responses have been compared for scaled distances based on the distance to the source and the weight of the explosive material. As a result, it can be seen that although concrete deformation has been restricted using the steel tube, the inner layer of concrete has been seriously damaged and the column displacement has been decreased by increasing the scaled distance. We also concluded that the concrete-filled steel columns have the high ductility and the blast resistance.
Blast Load
Concrete-Filled Steel Columns
Finite element analysis
2017
10
01
283
292
http://jacm.scu.ac.ir/article_12816_61de52714fc3fee52a1fac894b72a08b.pdf
Journal of Applied and Computational Mechanics
J. Appl. Comput. Mech.
2017
3
4
Modified U-Slot Stacked Micro-Strip Patch Antenna for Ultra-Wideband Applications in S Band, C Band and X Band
Monika
Surana
Amit
Jain
The U-slot micro-strip patch antennas were originally developed for bandwidth broadening applications. This study presents a transmission line feed to modify the U-slot stacked rectangular micro-strip patch antenna for Ultra-Wide Band (UWB) communications. The modified antenna has a U-cut loaded with parallel slits and corner slots and is printed on a dielectric substrate of FR4 with relative permittivity (εr) of 4.4, the thickness of 1.59 mm and the tangent loss of 0.025. The results show that the proposed antenna achieves an impedance bandwidth of 11.55 GHz (2.1 – 13.65 GHz) with the return loss < (-10) dB. This antenna can be employed for ultra-wideband applications in S Band, C Band and X Band. The proposed patch antenna is designed and simulated by using IE3D 14.0 software. Simulation results are presented in terms of the resonant frequency, the return loss, VSWR, the impedance bandwidth and the impedance matching.
UWB antenna
VSWR
IE3D & Return Loss
2017
10
01
293
301
http://jacm.scu.ac.ir/article_12638_eb623a5a8e7d4b143d2c81d82738d370.pdf