Remaining Creep Life Assessment of Gas Turbine Blade Made of IN 792 Nickel-Base Superalloy
Abolfazl
Karimi
سازمان صنایع هوایی
author
Hossein
Yarmohammad
سازمان صنایع هوایی
author
Mohammad Mehdi
Barjesteh
سازمان صنایع هوایی
author
Mohammad
Noori
سازمان صنایع هوایی
author
Hossein
Mohammad Karimi Yazdi
سازمان صنایع هوایی
author
text
article
2016
per
During the operation, the turbine blades of hot gas path suffer service induced degradation due to different causes such as creep, fatigue, oxidation, corrosion and etc. The present study was carried out the effect of long-term service at the high temperature exposure to remaining life assessment gas turbine blade made of Inconel 792 nickel base superalloy. That is investigated by studying on microstructure by optical and scanning electron microscopy, mechanical properties such as high temperature tensile and stress-rupture test and stress analyses of turbine blade. The result has been shown the gamma prime rafting and TCP phase formation has occurred at the microstructure. Because of long-term service at high temperature, stress- rupture properties of blade reduced and 20% lower than new IN 792 alloys. The stress analyses with ANSYS software and creep life assessment results by use Larson-miller parameter, the safety factor of blade lower than 1 and life time of turbine blade is finished.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
18
v.
3
no.
2016
6
18
http://jmep.isme.ir/article_22949_2e29bc33fe1c23c4fe31e455c2174c0c.pdf
Buckling and free vibration analysis of cylindrical panel reinforced by various distributions of CNTs on elastic foundation
مهدی
محمدی مهر
کاشان
author
سید محمد
اخوان علوی
دانشگاه کاشان
author
سید وحید
اخروی
دانشگاه کاشان
author
text
article
2016
per
In this paper, buckling and free vibration analysis of cylindrical panel reinforced by various distributions of carbon nanotubes (CNTs) on elastic foundation for two cases including uniform distributed (UD) and functionally graded (FG) is studied. Based on the first order shear deformation theory (FSDT), the equilibrium equations of cylindrical panel reinforced by CNTs are derived using energy method and Hamilton’s principle. Then, using Navier’s type solution, the governing equations of equilibrium for cylindrical panel reinforced by various distributions of CNTs are solved. Using the mixture rule, the material properties of cylindrical panel reinforced by CNTs are estimated. In this study, the effects of volume fraction, various distributions of CNTs, elastic foundation parameters on the critical buckling load and natural frequency of cylindrical panel reinforced with CNTs are investigated. The obtained results of this research indicate that the trend of increasing natural frequency leads to increase in the percentage of CNTs and elastic modulus parameters which the maximum natural frequency occurs for FG-X case. Also increasing the percentage of CNTs and elastic modulus parameters leads to increase the critical buckling load which the maximum and minimum values of this load take place for FG-X and FG-O, respectively. On the other hands, it can conclude that with suitable selecting of CNTs distributions and volume fraction, the stiffness of structures increases and then the critical buckling load and natural frequencies enhance. Thus this point is noticeable to design the optimum of structures at nanoscale.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
18
v.
3
no.
2016
19
44
http://jmep.isme.ir/article_22950_759b6122e2c9163e753aa6c53e5612e1.pdf
Outplane stress analysis of a functionally graded strip bounded with two elastic half plane including several finite cracks in interfacial zone between the strip and half plane
Rasoul
Bagheri
Assistant professor, Department of Mechanical Engineering, Islami Azad University of Karaj Branch
author
Mojtaba
Ayatollahy
Associate professor, Faculty of Engineering, Zanjan University
author
Mojtaba
Mahmoodi Monfared
Assistant professor, Department of mechanical engineering, Islami Azad Unviversity of Hashtgerd
author
text
article
2016
per
In this paper, analyses of several finite cracks in bonded materials with a graded interfacial zone were studied. The distributed dislocation technique is used to carry out stress analysis for two elastic half planes bonded through a non-homogeneous interfacial zone under anti-plane loading. The solution is obtained by means of Fourier transform method. The stress components reveal the familiar Cauchy singularity at the location of dislocation. Finally several examples are solved and the numerical results for the stress intensity factor are obtained. The influences of the geometric parameters, the thickness of the functionally graded strip and the crack size have significant effects on the stress intensity factors of crack tips which are displayed graphically.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
18
v.
3
no.
2016
45
60
http://jmep.isme.ir/article_22952_2e291997ae8aa8604b0d2dde45a41e31.pdf
Buckling analysis of circular cylindrical shells made of shape memory alloys in uniform temperature and axisymmetric loading using the exat and numerical solutions
Hadi
Vahidi
Msc., Department of Mechanical Engineering, Islamic Azad University of Karaj Branch
author
text
article
2016
per
In recent years, Shape Memory Alloys have found a lot of interest among researchers andengineers. Material properties of SMA's change with temperature and stress. Also due to largestrains that may occure in them, geometrical nonlinearities encountered in the analysis ofSMA structures. These material and geometrical nonlinearities make difficulties in theanalysis of SMA structures. In this thesis a numerical model based on the differentialquadrature's method (DQM) is presented for the buckling analysis of circular cylindricalshells made of SMA material.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
18
v.
3
no.
2016
61
77
http://jmep.isme.ir/article_22953_385e1bac412d4939b4ac8f9279bbe22b.pdf
The effect of parameters of visco-Pasternak foundation on the vibration characteristic of a FG square plate integrated with FGP layers
Mohammad
Arefi
Assistant professor, Department of Mechanical University, Kashan University
author
text
article
2016
per
The present paper investigates vibration analysis of a functionally graded square plate integrated with two functionally graded piezoelectric layers as sensor or actuator resting on the elastic Visco-Pasternak foundation. All the mechanical and electrical properties except Poisson’s ratio can vary continuously and gradually along the thickness of the plate based on a power function. Electric potential was assumed as a quadratic function along the thickness direction and trigonometric function along the planar coordinate. Short circuited boundary conditions are considered on the top and bottom of functionally graded piezoelectric layers. The general constitutive relations in electromechanical systems are used for considering the effect of all mechanical and visco-Pasternak foundation parameters. These parameters are including the non-homogeneous indexes of core and piezoelectric layers, direct, shear and damping parameters of foundation. The obtained results present the effect of various mechanical and foundation parameters on the vibration responses of the system. The functionalities of two considered layers and core can be regarded independently and the effect of these indexes can be considered on the responses. The obtained results indicate that with increasing the non-homogeneous index of core and layers, the natural frequencies of the system decreases.
نشریه پژوهشی مهندسی مکانیک ایران
ISME
2538-4775
18
v.
3
no.
2016
78
95
http://jmep.isme.ir/article_22951_61d711a57685b042b03eae4d565558b8.pdf