Spreading of Plastic Zones in Functionally Graded Spherical Tanks Subjected to Internal Pressure and Temperature Gradient Combinations
abbas
heydari
M.Sc. in Structural Engineering, School of civil engineering, Sharif university of technology, Tehran
author
text
article
2015
eng
Thermo-Elasto-Plastic analyses of thick-walled spherical tanks made of functionally graded materials are investigated analytically. These tanks are subjected to positive or negative temperature gradient and internal pressure loadings separately or simultaneously. The power law modeling has been used for through-the-thickness variation of mechanical properties. von Mises yield criterion and Elastic-Perfectly-Plastic assumptions are used for describing the material behavior in plastic zones. The patterns of plastic zones spreading for various combinations of internal pressure and positive or negative temperature gradient are investigated. Numerical analyses conducted for the similar problems and excellent agreement with the analytical solutions observed. FG sphere subjected to internal pressure and negative temperature gradient yields at a lower pressure than the FG sphere subjected to internal pressure. Internal pressure and negative temperature gradient combination is the most critical loading combination and positive temperature gradient increases the capacity of FG spherical tank subjected to internal pressure.
Iranian Journal of Mechanical Engineering Transactions of the ISME
Iranian Society of Mechanical Engineering
1605-9727
16
v.
2
no.
2015
5
25
https://jmee.isme.ir/article_24903_0a771040b014258d646495624badf4b9.pdf
A New Model of Car Following Behavior Based on Lane Change Effects Using Anticipation and Evaluation Idea
Alireza
Khodayari
Department of Mechanical Enineering
Pardis Branch
Islamic Azad University
author
ali
ghaffari
Department of Mechanical Engineering, K .N. Toosi University of Technology, Tehran Iran
author
ali
kamali
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran Iran
author
farzam
tajdari
Department of Mechanical Engineering, Amirkabir University of Technology, Tehran Iran
author
text
article
2015
eng
This paper aims to investigate a new and intricate behavior of immediate follower during the lane change of leader vehicle. Accordingly, the mentioned situation is a transient state in car following behavior during which the follower vehicle considerably deviates from conventional car following models for a limited time, which is a complex state including lateral and longitudinal movement simultaneously.Based on closer inspection of microstructure behavior of real drivers, this transient state is divided into two stages of anticipation and evaluation. Afterwards, a novel adaptive neuro-fuzzy model considering human driving factors is proposed to simulate the behavior of real drivers. Comparison of model results and real traffic data shows that the proposed model can describe anticipation and evaluation behavior during a car following behavior with acceptable errors which leads to enhancement of car following applications like driving assistant and collision avoidance systems.
Iranian Journal of Mechanical Engineering Transactions of the ISME
Iranian Society of Mechanical Engineering
1605-9727
16
v.
2
no.
2015
26
38
https://jmee.isme.ir/article_24902_52c3d4b0b72ace3b12c5887567a75559.pdf
Mechanical and Thermal Stresses In a Linear Plastic FGM Hollow Cylinder Due to Axisymmetric Loads
Milad
Shokouhfar
Islamic azad university, South Tehran branch
author
Mohammad reza
Eslami
Professor and Fellow of the Academy of Sciences, Mechanical Engineering, Department of Mechanical Engineering
, Amirkabir University of Technology, Tehran, Iran
author
Mohsen
Jabbari
Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Iran
author
Atefeh
Hatefkia
Department of Mechanical Engineering, South Tehran Branch, Islamic Azad University, Iran
author
text
article
2015
eng
In this paper, an analytical solution for computing the linear plastic stresses and critical temperature and pressure in a FGM hollow cylinder under the internal pressure and temperature is developed. It has been assumed that the modulus of elasticity and thermal coefficient of expansion were varying through thickness of the FGM material according to a power law relationship. The Poisson's ratio was considered constant throughout the thickness. The general form of thermal and mechanical boundary conditions is considered on the inside surfaces. In the analysis presented here the effect of non-homogeneity in FGM cylinder was implemented by choosing a dimensionless parameter, named m, which could be assigned an arbitrary value affecting the stresses in the cylinder. Distribution of stresses in radial and circumferential directions for FGM cylinders under the influence of internal pressure and temperature gradient were obtained. Graphs of variations of stress, critical temperature and pressure versus radius of the cylinder were plotted. Cases of pressure, temperature loadings were considered separately. The direct method is used to solve the heat conduction and Navier equations.
Iranian Journal of Mechanical Engineering Transactions of the ISME
Iranian Society of Mechanical Engineering
1605-9727
16
v.
2
no.
2015
39
65
https://jmee.isme.ir/article_24904_7d2a20b80204be149a7a41de16f8076b.pdf
Friction stir spot welding of polycarbonate by a new design tool
Eisa
Khoran
32 meteri of shohada- Shahid Kameli alley-64 plaque
author
Mohammad
Khoran
Lecturer in Esfarayen University
author
Seied Mostafa
Mousavizade Noghabi
Assistant Professor, Material Engineering, Hakim Sabzevari University
author
text
article
2015
eng
Microstructures, tensile properties and fracture energy of a friction stir spot welded polycarbonate (FSSW) were studied at varying rotational rates and dwelling time. The problem of common FSSW welding is the remaining of characteristic keyhole. This can act as a concentration place in mechanical tests. To order solve this problem authors took advantage of innovation for designing the welding tool. The results show that in constant dwell time, strengths increase until 800 rpm and then decreases. In constant rotational speed (400, 800) the strength increase by increasing in dwell time but in 1600 rpm the best result was achieved in 10 Sec dwell time. Fracture energy which was exploit from stress-strain curve were in good agreement with strength of welds.
Iranian Journal of Mechanical Engineering Transactions of the ISME
Iranian Society of Mechanical Engineering
1605-9727
16
v.
2
no.
2015
66
76
https://jmee.isme.ir/article_24905_32fbe6213b25190f2cb866a4a4e2ef3f.pdf
Fracture Analysis of a FGM Strip Containing Multiple Interface Cracks Sandwiched between Two Homogeneous Layers
rasul
bagheri
Mechatronics Faculty, Department of Mechanical Engineering, Karaj Branch, Islamic Azad Univeersity, Alborz, Iran, r.bagheri@kiau.ac.ir
author
hossein
lak
Mechatronics Faculty, Department of Mechanical Engineering, Karaj Branch, Islamic Azad University, Alborz, Iran
author
text
article
2015
eng
A FGM layer sandwiched between two isotropic layers weakened by several interface cracks under antiplane loading is studied. This paper examines the modelling of cracks by distribution of strain nuclei along crack lines. In this investigation, the Volterra-type screw dislocation employed between FGM and an elastic layer. To solve the dislocation problem, the complex Fourier transform is applied. One merit of this technique is the possibility to determination of the stress intensity factors for multiple cracks. The system of equations is derived by considering the distribution of line dislocation on the crack. These equations are of Cauchy singular type at the location of dislocation, which can be solved numerically to obtain the dislocation density on the faces of the cracks. Several examples are solved and the stress intensity factors are obtained. The effect of the properties and cracks geometries on the mode III stress intensity factor are studied and the validity of analysis is checked.
Iranian Journal of Mechanical Engineering Transactions of the ISME
Iranian Society of Mechanical Engineering
1605-9727
16
v.
2
no.
2015
77
91
https://jmee.isme.ir/article_24907_f7dd6af4943c9e49106587f7703ca742.pdf