ORIGINAL_ARTICLE
Nonlinear Vibration Analysis of Multi-Walled Carbon Nanotubes in Thermal Environment using the Nonlocal Timoshenko Beam Model
In this paper, based on the nonlocal Timoshenko beam theory, a nonlinear model is presented for the vibrational behavior of carbon nanotubes (CNTs) embedded in elastic medium in thermal environment. Using the Timoshenko beam theory and nonlocal elasticity of Eringen, the influences of rotary inertia, transverse shear deformation and small scale effect are taken into account. To model the interaction forces between walls, whether adjacent or non-adjacent, the van der Waals interlayer interactions are considered. The harmonic balance method (HBM) is used for the solution of the set of nonlinear governing equations and the frequency function of the system for the simply-supported boundary conditions is derived. Compared to the incremental harmonic balance method which has been employed in the previous studies, the HBM is simpler and has a reasonable accuracy. The effects of geometrical parameters of nanotubes such as the number of walls, the ratio of length to outer diameter and environmental conditions such as elastic medium modulus, temperature and also the effect of nonlocal parameter on the nonlinear frequency are investigated. The presented nonlinear vibration analysis is of a general form, so that they are applicable for CNTs with arbitrary number of walls. The obtained results for single-, double- and triple-walled CNTs indicate that with an increase in the number of walls, elastic medium modulus, aspect ratio and temperature, the value of nonlinear frequency tends to that of its linear counterpart. Also, a comparison between the results of the Timoshenko beam theory and those of Euler-Bernoulli beam theory shows that the difference between the frequency responses of these theories is significant for short CNTs, but, as the length increases, the difference between the results becomes negligible.
http://jsme.iaukhsh.ac.ir/article_515357_833fdb3951c91f21165db384d8921d8f.pdf
2011-06-22
1
9
Multi-walled Carbon Nanotubes
Nonlocal Timoshenko beam theory
Harmonic balance method
Thermal environment
Abolhasan
Nazarinezhad Giashi
nazarinezhad@iauroudbar.ac.ir
1
Instructor, Islamic Azad University, Rouudbar Branch
LEAD_AUTHOR
Reza
Ansari
r_ansari@guilan.ac.ir
2
Assistant Professor, Faculty of Engineering, University of Guilan
AUTHOR
Habib
Ramezannezhad Azarboni
3
Ph.D. Candidate, Faculty of Engineering, University of Guilan
AUTHOR
ORIGINAL_ARTICLE
Thermal Effect on the Torsional Buckling of Double Walled Carbon Nanotube Embedded in Pasternak Foundation
In this study the effect of thermal stress on the torsional buckling of double walled carbon nanotubes is investigated. Moreover based on nonlocal continuum mechanic the buckling governing equations are obtained and equilibrium of Equations is generalized to double wall nanotubes. Also in this study the elastic medium, small scale effect and van der Walls force are considered. Also for simulation of the interaction between the polymer matrix and external tube Pasternak model is used. The numerical results indicate that critical buckling load occurs in the middle modes. Moreover for the Winkler related the Pasternak model the buckling occurs earlier. Results show that for rigid elastic medium in both case of Pasternak and Winkler models the buckling load is independent of their values Moreover from the result it can be seen that the buckling load has been increase as the thermal effect change.
http://jsme.iaukhsh.ac.ir/article_515359_37ed629cb8fd6ffc583d675305667b8a.pdf
2011-06-22
11
16
Double walled carbon nanotube
Thermal buckling
Nonlocal continuum mechanic
Elastics medium
Pasternak model
Ali
Ghorbanpour Arani
aghorban@kashanu.ac.ir
1
Associate Professor, Faculty of Engineering, Kashan University, Kashan
LEAD_AUTHOR
Mohammad
Sharif Zarei
2
Ph.D. Student, Faculty of Engineering, Kashan University, Kashan
AUTHOR
Mehdi
Mohammadimehr
3
Assistant Professor, Faculty of Engineering, Kashan University, Kashan
AUTHOR
[1] S. Iijima, Helical Micro Tubes of Graphitic Carbon, Nature, 354, 1991, pp. 56-58.
1
[2] S. Rodney Ruoff, Q. Dong, L. Wing Kam, Mechanical properties of carbon nanotubes: theoretical predictions and experimental measurements, C. R. Physique,4, 2003, pp. 993-1008
2
[3] A. Ghorbanpour Arani, R. Rahmani, A. Arefmanesh, S. Golabi, Buckling Analysis of Multi-Walled Carbon Nanotubes under Combined Loading Considering the Effect of Small Length Scale, Journal of Mechanical Science and Technology, 22, 2008, pp. 429-439.
3
[4] Ru CQ., Elastic buckling of single-walled carbon nanotube ropes under high pressure, Physics Review B, 62, 2000, pp. 10405–10408.
4
[5] M.J. Hao, X.M. Guo, Q. Wang., Small-scale effect on torsional buckling of multi-walled carbon nanotubes, European Journal of Mechanics A/Solids, 29, 2010, pp. 49-55.
5
[6] Y.C. Zhang, X. Chen, X. Wang., Effects of temperature on mechanical properties of multi-walled, Composites Science and Technology, 68, 2008, pp. 572-581.
6
[7] A.C. Eringen, On differential equations of nonlocal elasticity and solutions of screw dislocation and surface waves, Journal of Applied Physics, 54, 1983, pp. 4703-4710.
7
[8] S. Kitipornchai, X. Q. He, and K. M., Buckling analysis of triple-walled carbon nanotubes embedded in an elastic matrix, Journal of Applied Physics., 97, 2005, pp.114318-114325.
8
[9] T. Murmu, S.C. Pradhan., Thermal effects on the stability of embedded carbon nanotubes, Computational Materials Science, 47, 2010, pp. 721-726.
9
[10]S. Chengqi, L. Kaixin, Dynamic torsional buckling of a double-walled carbon nanotube embedded in an elastic medium, European Journal of Mechanics A/Solids, 27, 2008, pp. 40–49.
10
[11]A.C. Eringen, Nonlocal Continuum Field Theories, Springer-Verlag, New York, 2002
11
[12] Mohammadimehr M., Saidi A.R., Ghorbanpour Arani A., Arefmanesh A. , Torsional buckling of a DWCNT embeddedon winkler and pasternak foundations using nonlocal theory, Journal of Mechanical Science and Technology,24(6), 2010, pp.1289-1299
12
[13]Y. Xiaohu, H. Qiang, The thermal effect on axially compressed buckling of a double-walled carbon nanotube, European Journal of Mechanics A/Solids, 26, 2007, pp. 298–312.
13
ORIGINAL_ARTICLE
A New Strain Based Model for Predicting Multiaxial Fatigue Life of Metals
Engineering structures are usually exposed to cyclic multiaxial loading and subsequently to multiaxial fatigue. Different models and criteria with various capabilities have been proposed for predicting of multiaxial fatigue life. Selection of proper model by considering material, type of loading and operation condition of each engineering structure is a challenging issue of the life prediction process. In this paper, capability of some critical strain-based models for predicting the fatigue life are evaluated and compared. Then, based on the advantages and disadvantages of the investigated models, a new model is presented. In this study, experimental fatigue data for SNCM630 samples under axial-torsional loading are used which is available in the literature. Results are compared to experimental data in order to validate the accuracy and capability of the new model in prediction of the fatigue life.
http://jsme.iaukhsh.ac.ir/article_515360_746043b74caa260ed4390274042be2f9.pdf
2011-06-22
17
25
Multiaxial fatigue
Fatigue Life
Strain-based model
Critical plane-based mode
Rahmat-Allah
Ghajar
ghajar@kntu.ac.ir
1
Professor, Mechanical Engineering Department, K. N. Toosi University of Technology
LEAD_AUTHOR
Safa
Peyman
2
- Ph.D. Student, Mechanical Engineering Department, K. N. Toosi University of Technology
AUTHOR
Javad
Alizadeh K
3
Ph.D. Student, Mechanical Engineering Department, K. N. Toosi University of Technology
AUTHOR
[1] Socie D. F. ,Marquis G. B., Multiaxial Fatigue, 1st ed., SAE,2000.
1
[2] Han C., Chen X. , Kim K. S., Evaluation of multiaxial fatigue criteria under irregular loading, Int. J. of Fatigue, 24 (9), 2002, pp. 913-922.
2
[3] Brown M., Miller K. A theory for fatigue failure under multiaxial stress-strain conditions, Proceedings of Institute of Mechanical Engineers, Vol. 187, 1973,pp. 745-756.
3
[4] Fatemi A. ,Socie D. F., A critical plane approach to multiaxial fatigue damage including out-of-phase loading, Fatigue and Fracture of Engineering Materials and Structures, 11 (3), 1988, pp. 449-466.
4
[5] Smith R. N., Watson P., Topper T. H., A stress strain parameter for the fatigue of metal, Journal of Materials, 5 (4), 1970, pp. 767-778.
5
[6] Liu K. C., A method based on virtual strain-energy parameters for multiaxial fatigue life prediction, ASTM STP 1191, American Society for Testing and Materials, 1993, pp. 67-84.
6
[7] Chu C. C., Conle F. A. , Bonnen, J. F.,. Multiaxial stress-strain modeling and fatigue life prediction of SAE axel shaf, ASTM STP 1191, American Society for Testing and Materials, 1993, pp. 37-54.
7
[8] Glinka G., Wang G., Plumtree A., Mean stress effects in multiaxial fatigue, Fatigue and Fracture of Engineering Materials and Structures, 18 (7/8), 1995,pp. 755-764.
8
[9] Dowling N. E., Mechanical behavior of materials, 3st ed., Prentice Hall. 2006.
9
ORIGINAL_ARTICLE
Study of Aspect Ratio Effect on Mechanical Properties Polymer/NanoComposite
Carbon nanotubes (CNTs) demonstrate unusually high stiffness, strength and resilience, and are therefore an ideal reinforcing material for nanocomposites. However, much work has to be done before the potentials of CNT-based composites can be fully realized. Evaluating the effective material properties of such nanoscale materials is a very difficult tasks. Simulations using molecular dynamics and continuum mechanics models can play significant roles in this development. Currently, the continuum approach seems to be the only feasible approach for such large scale analysis. In this paper, effective mechanical properties of CNT-based composites are evaluated using a square representative volume element (RVE) based on the continuum mechanics and Finite Element Method (FEM). Formulas are derived based on the elasticity theory to extract the effective material constants from solutions for the square RVEs under two load cases. Next, CNT aspect ratio effects on the nanocomposite mechanical properties are investigated. Results indicate that increasing CNT aspect ratio results in an increase in nanocomposite longitudinal modulus and a decrease in nanocomposite transverse modulus. Also, increasing the CNT aspect ratio resulted in a decrease in nanocomposite Poisson’s ratio in the x-y plane and an increase in nanocomposite Poisson’s ratio in the x-z plane.
http://jsme.iaukhsh.ac.ir/article_515361_b9de5ca5c473c163250e301dfee9cd54.pdf
2011-06-22
27
34
nanocomposite
Carbon Nanotube
Aspect Ratio
Finite Element Analysis
Mechanical Properties
Mohamad
Hashemi Gahruei
1
M.Sc. Student, Shahrekord University
AUTHOR
Hossein
Golestanian
golestanian@eng.sku.ac.ir
2
Associate Professor, Faculty of Engineering, Shahrekord University
LEAD_AUTHOR
Mehdi
Salmani Tehrani
3
Assistant Professor, Department of Mechanical Engineering, Esfahan University of Technology
AUTHOR
1] Iijima S., Helical Microtubes of Graphitic Carbon, Nature (London), 354, 1991, pp. 56-58.
1
[2] Liu Y., Nishimura N., d Otani Y., Large-scale modeling of carbon-nanotube composites by a fast multiple boundary element method, Computational Materials Science, 34, 2005, pp. 173-187.
2
[3] Thostenson E.T., Chunyu L., Chou T.W., Nanocomposites in context, Composites science and Technology, 65, 2004, pp. 491-516.
3
[4] Golestanian H., Shojaie M., Numerical characterization of VNT-based polymer composites considering interface, Computational Material Science, 50, 2010, pp. 731-736.
4
[5] Matin Ghahfarokhi Z., Golestanian H., Effects of nanotube helical angle on mechanical properties of carbon nanotube reinforced polymer composites, Computational Material Science, 50, 2011, pp. 3171–3177.
5
[6] Liu J., Chen X.l., Evaluation of the effective material properties of carbon nanotube-based composites using a nanoscale representative volume element, Mechanics of Materials, 35, 2003, pp. 69-81.
6
[7] Florian H.G., Wichmann M., Fiedler B., Schulte K., Influence of different carbon nanotubes on the mechanical properties of epoxy matrix composites – A comparative study, Composite Science and technology, 65, 2005, pp. 2300–2313.
7
[8] Cornwell C.F., Wille L.T., Elastic Properties of single-walled carbon nanotubes in compression, Solid State Communication, 101, 1997, pp. 555-558.
8
[9] Gao G.H., Cagin T., Goddard W.A., Energetic, structure, mechanical and vibrational properties of single-walled carbon nanotubes, Nanotechnology, 9, 1998, pp. 187-191.
9
[10] Nardelli M.B., Fattebert J.L., Mechanical properties, defects and electronic behavior of carbon nanotubes, Carbon, 38, 2000, pp. 1703-1711.
10
[11] Wong E.W., Sheehan P.E., Lieber C.M., Nanobeam mechanics: Elasticity, strength and toughness of nanorods and nanotubes, Science, 227, 1997, pp. 1971-1975.
11
[12] Ruoff R., Lorents D.C., Mechanical and thermal properties of carbon nanotubes, Carbon, 33, 1995, pp. 925-930.
12
[13] Salvetat J.P., Bonard J.M., Thomson N.H., Kulik A.J., Mechanical properties of carbon nanotubes, Applied Physics A-Materials Science and Processing , 69, 1999, pp. 225-260.
13
ORIGINAL_ARTICLE
Investigation of Important Parameters in Residual Stress Determination in Isotropic Plates and Laminated Composites by Slitting Method
In the slitting method, a small width slit is created incrementally through the thickness of the stressed specimen and the released strains in each increment are recorded by a strain gauge. Compliance coefficients relate the measured strains to the residual stresses. This paper investigates the important parameters influencing the calculation of compliance coefficients for isotropic plates and laminated composites by finite element analysis. First, the process of slitting in isotropic materials is simulated using two and three-dimensional finite element models. The results show complete agreement between these two models. Calculation of average strain at the strain gauge location is necessary for the calculation of compliance coefficients. For this purpose, strain-based and displacement-based methods are used. In addition, the effect of slit width on compliance coefficients is checked. Then, released strains by strain gauges with different gauge-lengths are compared with each other. The results show that the strain gauges with smaller gauge-lengths can record higher values of released strain and consequently increase the precision of measurements. Lastly, compliance coefficients for two glass/epoxy and carbon/epoxy laminates are calculated using the proposed three-dimensional model.
http://jsme.iaukhsh.ac.ir/article_515362_9bdd182a88d6d7e8a337c1f4ad4274bf.pdf
2011-06-22
35
45
Residual stresses
Slitting Method
Polymer Composites
Compliance Coefficients
Inite Element Analysis
Mahmood
Mehrdad Shokrieh
shokrieh@iust.ac.ir
1
Professor, Iran University of Science and Technology
LEAD_AUTHOR
Saeid
Akbari
2
M. Sc. Student, Iran University of Science and Technology.
AUTHOR
[1] Gascoigne H.E., Residual Surface Stresses in Laminated Cross-Ply Fiber- epoxy Composite Materials, Experimental Mechanics, 34:1, 1994, pp. 7-36.
1
[2] Ersoy N., Vardar O., Measurement of Residual Stresses in Layered Composites by Compliance Method, Journal of Composite Materials, 34:7, 2000, pp. 575–598,
2
[3] Vaidyanathan S., Finnie I., Determination of Residual Stresses from Stress Intensity Factor Measurements, Journal of Basic Engineering, 93, 1971, pp. 242-246.
3
[4] Cheng W., Finnie I., A Method for Measurement of Axisymmetric Residual Stresses in Circumferentially Welded Thin-Walled Cylinders, Journal of Engineering Materials and Technology, 107, 1985, pp.181-185.
4
[5] Cheng, W., and Finnie, I., Measurement of Residual Hoop Stress in Cylinders Using the Compliance Method, Journal of Engineering Materials and Technology, 108, 1986, pp. 87-92.
5
[6] Kang K.J., Song J.H., Earmme Y.Y., A Method for the Measurement of Residual Stresses Using a Fracture Mechanics Approach, J. Strain Anal. Eng. Des., 24, 1989, pp. 23-30.
6
[7] Schajer G., Prime M.B., Residual Stress Solution Extrapolation for the Slitting Method Using Equilibrium Constraints, Journal of Engineering Materials and Technology, 129, 2007, pp. 227-232,
7
[8] Prime M. B., Plasticity Effects in Incremental Slitting Measurement of Residual Stresses, Engineering Fracture Mechanics, 77:10, 2010, pp. 1552-1566.
8
[9] Prime M.B., Residual Stress Measurement by Successive Extension of a Slot: The Crack Compliance Method, Journal of Applied Mechanics, 52: 2, 1999, pp. 75-96.
9
[10] Hermann R., Crack Growth and Residual Stress in Al-Li Metal Matrix Composites Under Far-Field Cyclic Compression, Journal of Materials Science, 30:15, 1995, pp. 3782–3790.
10
[11] Prime M.B., Hill M.R., Measurement of Fiber-Scale Residual Stress Variation in a Metal-Matrix Composite, Journal of Composite Materials, 38: 23, 2004, pp. 2079-2095.
11
[12] Hill M.R., Lin W.Y., Residual Stress Measurement in a Ceramic-Metallic Graded Material, Journal of Engineering Materials and Technology, 124: 2, 2002, pp. 185–191.
12
[13] Lee M.J., Hill M.R., Effect of strain gage length when determining residual stress by slitting, Journal of Engineering Materials and Technology, 129:1, 2007, pp. 375-382.
13
[14] ANSYS Help System, Analysis Guide and Theory Reference, Ver. 12.
14
[15] Schajer G.S., Use of Displacement Data to Calculate Strain Gauge Response in Non- Uniform Strain Fields, Strain , 29:1, 1993, pp. 9-13,.
15
[16] Shokrieh M.M., and Ghasemi A.R., Simulation of Central Hole Drilling Process for Measurement of Residual Stresses in Isotropic, Orthotropic and Laminated Composites Plates, Journal of Composite Materials, 41, 2007, pp. 435-452.
16
[17] Prime, M. B., and Hill, M.R., Uncertainty, Model Error, and Order Selection for Series-Expanded, Residual-Stress Inverse Solutions, Journal of Engineering Materials and Technology, 128, 2006, pp. 175–185.
17
ORIGINAL_ARTICLE
Fluid-structure Interaction Vibration Analysis of Vertical
Cylindrical Containers with Elastic Bottom Plate Made
of Functionally Graded Materials
In the present paper a method is proposed to investigate the free vibration of a partially liquid-filled cylindrical tank. The mechanical properties of the container are assumed to change continuously along the thickness according to volume fraction Power-law, Sigmoid or Exponential distribution. The liquid is supposed to be incompressible and in viscid and its velocity potential is formulated by using Eigen function expansions. The interaction between the liquid and the plate was considered and the dynamic characteristics of the plate are extracted by using the Rayleigh–Ritz method. The results from the proposed method are in good agreement with experimental and numerical solutions available in the literature. A finite element analysis is also applied to check the validity of the results. Furthermore, the influence of various variables such as the number of nodal circles and diameters, volume fractions of functionally graded materials and liquid level on the dynamic behavior of the coupled system is investigated.
http://jsme.iaukhsh.ac.ir/article_515363_2fa2afdfc974ac494b7b106385bcd8ab.pdf
2011-06-22
47
61
Free vibration
Liquid–structure interaction
Functionally Graded Materials
Rayleigh–Ritz method
Eigen function expansion
Ali Akbar
Shafiee
1
Master of Science, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
AUTHOR
Mojtaba
Mahzoon
mahzoon@shirazu.ac.ir
2
Associate Professor, School of Mechanical Engineering, Shiraz University, Shiraz, Iran
LEAD_AUTHOR
Ehsan
Askary
3
Australian School of Advanced Medicine, Macquarie University, Sydney, Australia
AUTHOR
[1] Kwak M.K., Kim K.C., Axisymmetric vibration of circular plates in contact with fluid, Journal of Sound and Vibration, 146, 1991, pp. 381–389.
1
[2] Kwak M.K. , Vibration of circular plates in contact with water, Transactions of the American Society of Mechanical Engineers, Journal of Applied Mechanics, 58, 1991, pp.480–483.
2
[3] Chiba M., Nonlinear hydroelastic vibration of a cylindrical tank with an elastic bottom, containing liquid. Part II: linear axisymmetric vibration analysis, Journal of Fluids and Structures, 7, 1993, pp. 57–73.
3
[4] Bauer H.F., Coupled frequencies of a liquid in a circular cylindrical container with elastic liquid surface cover, Journal of Sound and Vibration, 180, 1995, pp. 689–704.
4
[5] Amabili M., Bulging modes of circular bottom plates in rigid cylindrical containers filled with a liquid, Shock and Vibration, 4, 1997, pp. 51–68.
5
[6] Kwak M.K., Han S.B., , Effect of fluid depth on the hydroelastic vibration of free-edge circular plate, Journal of Sound and Vibration, 230, 2000, pp. 171–185.
6
[7] Amabili M., Kwak, M.K., ,Vibration of circular plates on a free fluid surface; effect of surface waves, Journal of Sound and Vibration, 226, 1999, pp. 407–424.
7
[8] Cheung Y.K., Zhou D., Hydroelastic vibration of a circular container bottom plate using the Galerkin method, Journal of Fluids and Structures, 16, 2002, pp. 561–580.
8
[9]Liang C. C., Liao C. C., Tai Y. S., The free vibration analysis of submerged cantilever plates, Ocean Engineering, 28, 2001, pp.1225–1245.
9
[10] Jeong K.H., Kim K.J., Hydroelastic vibration of a circular plate submerged in a bounded compressible fluid, Journal of Sound and Vibration, 283, 2005, pp. 153–172.
10
[11] Jeong K.H., Hydroelastic vibration of two annular plates coupled with a bounded compressible fluid, Journal of Fluids and Structures, 22, 2006, pp. 1079–1096.
11
[12] Askari E., Daneshmand F., Free vibration of an elastic bottom plate of a partially fluid-filled cylindrical container with an internal body, European Journal of Mechanics A/Solids, 29, 2010, pp. 68–80.
12
[13]Kutlu A., Ugurlu B., Omurtag M.H., Ergin A., Dynamic response of Mindlin plates resting on arbitrarily orthotropic Pasternak foundation and partially in contact with fluid, Ocean Engineering, 42, 2012, pp. 112–125.
13
[14] Yamanouchi M., Koizumi M., Hirai T., Shiota, Resonances of an air-filled elastic cylindrical shell immersed in a fluid, Proceedings of the First International Symposium on Functionally Gradient Materials, Japan ,1990.
14
[15] Koizumi M., The concept of FGM, Ceramic Transactions, Functionally Gradient Materials, 1993, pp. 34, 3–10.
15
[16] Anon, FGM components: PM meets the challenge, Metal Powder Report, 51, 1996, pp. 28–32.
16
[17] Reddy J. N., , Analysis of functionally graded plates, International journal for numerical method in engineering- International Journal for Numerical Methods in Engineering, 47, 2000, pp. 663–684.
17
[18] Nie G.J., Zhong Z., Semi-analytical solution for three-dimensional vibration of functionally graded circular plates, Computer Methods in Applied Mechanics and Engineering, 196, 2007, pp. 4901–4910.
18
[19] Allahverdizadeh A., Naei M. H., Nikkhah Bahrami M., Nonlinear free and forced vibration analysis of thin circular functionally graded plates, Journal of Sound and Vibration, 310, 2008, pp. 966–984.
19
[20] Dong C. Y., Three-dimensional free vibration analysis of functionally graded annular plates using the Chebyshev–Ritz method, Materials and Design, 29, 1995, pp.1518–1525.
20
[21] Chen W.Q., Bian Z.G., Ding H.J., 3D free vibration analysis of a functionally graded piezoelectric hollow cylinder filled with compressible fluid, International Journal of Solids and Structures, Vol. 41, 2004, pp. 947–964.
21
[22] Morand H.J.P., Ohayon, R., Fluid–Structure Interaction: Applied Numerical Methods, Wiley, New York, 1995.
22
[23] Delale F., Erdogan, F., The crack problem for a nonhomogeneous plane, ASME Journal of Applied Mechanics, 50, 1983, pp.609–614.
23
[24] Shyang-Ho Chi., Yen-Ling Chung., Mechanical behavior of functionally graded material plates under transverse load—Part I: Analysis, International Journal of Solids and Structures, 43, 2006, pp. 3657–3674.
24
[25] Leissa A.W., , Vibration of Plates, NASA SP-160. U.S Government Printing Office, Washington, DC., 1969.
25
[26] Askari E., Daneshmand, F., ,Coupled vibration of a partially fluid-filled cylindrical container with a cylindrical internal body, Journal of Fluids and Structures, 25, 2009, pp. 389–405.
26
[27] Amabili M., Shell-plate interaction in the free vibrations of circular cylindrical tanks partially filled with a liquid: the artificial spring method, Journal of Sound and Vibration, 199, 1997, pp.431–452.
27
[28] Zhu F., Rayleigh quotients for coupled free vibrations, Journal of Sound and Vibration, 171, 1994, pp. 641–649.
28
[29] Virella J., Godoy L., Su´arez, L., Fundamental modes of tank-liquid systems under horizontal motions, Engineering Structures, 28, 2006, pp. 1450–1461.
29
[30] Ergin A., Ugurlu B., Hydroelastic analysis of fluid storage tanks by using a boundary integral equation method, Journal of Sound and Vibration, 17, 2004, pp. 927–939.
30
[31] Koval’chuk, Kruk P. S., On the spectrum of natural frequencies of circular cylindrical shells completely filled with a fluid, International Applied Mechanics, 42, 2006, pp. 529-535.
31
ORIGINAL_ARTICLE
Static Analysis of Orthotropic Functionally Graded Material Cylinders with Finite Length by a Mesh-Free Method
In this paper static analysis of orthotropic functionally graded material (FGM) cylinders with finite length was carried out by a mesh-free method. MLS shape functions are used for approximation of displacement field in the weak form of equilibrium equation and essential boundary conditions are imposed by transformation method. In this simulation, an ax symmetric model is used. Mechanical properties of cylinders were assumed to be variable in the radial direction as a function of volume fraction. In this analysis, effects of the cylinder thickness and length, volume fraction exponent, type of materials layout and essential boundary conditions on displacement fields and stress distribution for orthotropic cylinders are investigated. The results of the proposed method for isotropic FGM cylinders were compared with corresponding results obtained from FEM and previous published works and a very good agreement are seen between them. Also by comparing the stress distributions of orthotropic FGM cylinders and corresponding results of homogeneous multilayered orthotropic cylinders were confirmed.
http://jsme.iaukhsh.ac.ir/article_515364_054be4588069bd5bb6af32abc61f4d94.pdf
2011-06-22
63
75
FGM
Mesh-Free
Orthotropic Cylinder
Static Analysis
Transformation function
Rasoul
Moradi-Dastjerdi
1
M.Sc. Graduated, Young Researchers Club, Khomeinishahr Branch, Islamic Azad University, Khomeinishahr, Iran
AUTHOR
Mehrdad
Foroutan
foroutan@razi.ac.ir
2
Assistant Professor, Mechanical Engineering Department, Razi University, Kermanshah, Iran
LEAD_AUTHOR
Somayeh
Abdollahi-Backtash
3
M.Sc. Graduated, Mechanical Engineering Department, Razi University, Kermanshah, Iran
AUTHOR
[1] Horgan C.O., Chan A.M., The pressurized hollow cylinder or disk problem for functionally graded isotropic linearly elastic materials, Journal of Elasticity, 55(1), 1999, pp. 43–59.
1
[2] Tutuncu N., Ozturk M., Exact solutions for stresses in functionally graded pressure vessels, Journal of Composite part B, 32(8), 2001, pp. 683-686.
2
[3] Jabbari M., Bahtui A., Eslami M.R., Axisymmetric mechanical and thermal stresses in thick long FGM cylinders, Journal of Thermal Stresses, 29(7), 2006, pp. 643–63.
3
[4] Tutuncu N., Stresses in thick-walled FGM cylinders with exponentially-varying properties, Engineering Structures, 29(9), 2007, pp. 2032-35.
4
[5] Li, X, Peng X., A Pressurized Functionally Graded Hollow Cylinder with Arbitrarily Varying Material Properties, Journal of Elasticity, 96, 2009, pp. 81-95.
5
[6] Tutuncu N., Temel B., A novel approach to stress analysis of pressurized FGM cylinders, disks and spheres, Composite Structures, 91(3), 2009, pp. 385-90.
6
[7] Nie G.J., Batra R.C., Static deformations of functionally graded polar-orthotropic cylinders with elliptical inner and circular outer surfaces, Composites Science and Technology, 70, 2010, pp. 450–457.
7
[8] Ye, J.Q., Sheng, H.Y., Free-edge effect in cross-ply laminated hollow cylinders subjected to axisymmetric transverse loads, International Journal of Mechanical Sciences, 45, 2003, pp. 1309–1326.
8
[9] Sobhani Aragh B., Yas, M. H., Static and free vibration analyses of continuously graded
9
ﬁber-reinforced cylindrical shells using generalized power-law distribution, Acta Mechanica, 215, 2010, pp. 155–173.
10
[10] Sladek J., Sladek, Zhang V., Stress analysis in anisotropic functionally graded materials by the MLPG method, Engineering Analysis with Boundary Elements, 29, 2005, pp. 597–609.
11
[11] Ching H.K. Yen, S.C. Meshless local Petrov-Galerkin analysis for 2d functionally graded elastic solids under mechanical and thermal loads, Journal Composite part B, 36(3), 2005, pp. 223-40.
12
[12] Sladek J., Sladek V., Zhang Ch., Transient heat conduction analysis in functionally graded materials by the meshless local boundary integral equation method, Computational Materials Science, 28(3-4), 2003, pp. 494–504.
13
[13] Gilhooley D.F., Xiao, Batra J.R., McCarthy R.C., Two-dimensional stress analysis of functionally graded solids using the MLPG method with radial basis functions, Computational Materials Science, 41(4), 2008, pp. 467-81.
14
[14] Sladek V., Sladek J., Zhang Ch., Local integral equation formulation for axially symmetric problems involving elastic FGM, Engineering Analysis with Boundary Elements, 32(12), 2008, pp. 1012-24.
15
[15] Zhao X., Liew K.M., A mesh-free method for analysis of the thermal and mechanical buckling of functionally graded cylindrical shell panels, Computational Mechanics, 45, 2010, pp. 297–310.
16
[16] Foroutan M., Moradi-Dastjerdi R., Sotoodeh-Bahreini R., Static analysis of FGM cylinders by a mesh-free method, Steel and Composite Structures, 12, 2012, pp. 1-11.
17
[17] Mollarazi H.R., Foroutan M., Moradi-Dastjerdi R., Analysis of free vibration of functionally graded material (FGM) cylinders by a meshless method, Journal of Composite Materials, 46(5) 2011, pp. 507–515.
18
[18] مرادی دستجردی ر.، فروتن م.، پوراصغر ا.، تحلیل ارتعاشات آزاد و اجباری استوانههایی ازجنس مواد هدفمند به روش بدون المان، فصلنامه علمی پژوهشی مهندسی مکانیک جامدات، شماره 5، 1388، صص 77-69.
19
ORIGINAL_ARTICLE
Study of Permanent Magnet Bearings and their Stiffness
A typical passive magnetic bearing has been modeled and analyzed for its performance characteristics. The magnetic bearing studied in this work comprised of a Shaft, inner magnets sleeved over the shaft, and outer magnetic rings. A detailed analysis has been perform on the force exerted by a permanent magnet on the shaft nurture to restore the shaft to its equilibrium position when an eccentricity is induced between the magnet and the shaft . A relation between the force exerted and the displacement of the shaft from its equilibrium position has been developed hence determining a specific stiffness value.
http://jsme.iaukhsh.ac.ir/article_515365_c75fb56b9b6b7ffdb40e440008f0ca22.pdf
2011-06-22
77
83
Active magnetic bearing
Electrodynamic effects
Magnetic flux
Stiffness
Mohammad
Esmaeili Adabi
m.esmailiadabi@shahryariau.ac.ir
1
Lecturer, Department of physics, Shahr-e-Qods Branch, Islamic Azad university, Tehran, Iran
LEAD_AUTHOR
Shahrbanoo
Farkhondeh
2
M.Sc., Department of Mechanical Engineering, Cleveland State University, U.S.A
AUTHOR
Majid
Rashidi
3
Assistant Professor, Department of Mechanical Engineering, Cleveland State University, U.S.A
AUTHOR
[1] Wikipedia, Free encyclopedia, Earnshow,s theorem, 1842.
1
[2] Backers F.T., A magnetic journal bearing, Phillips Tech. Rev., vol.22, 1961, pp.232- 238.
2
[3]Yonnet J.P., Permanent magnet bearings and couplings, IEEE Transactions on Magnetics, vol.17, No.1, 1981, pp. 1169-1173.
3
[4]Yonnet J.P., Lemarquand G., Hmmerlin S., and Olvierrulliere E., Stacked Structures Of Passive Magnetic Bearings, Jounnal of Applied Physics, Vol.70, No.10, 1991, pp.6633-6635.
4
[5]Marinescu M., and Marinescu N., A New Improved Method for Computation of Radial Stiffness in Permanent Magnet Bearings, IEEE Trans. Magn., Vol.30, No.5, 1994, pp.3491-3494.
5
[6]Paden B., Groom N., Antaki J.F., Design Formulas for Permanent- Magnet Bearings, Transactions of the ASME, Vol.125, 2003, pp.734-738.
6
[7]Meeker D., Radial Magnetic Bearing: Example, 1999.
7
[8]Siebert M., Passive Magnetic Bearing Development, 2002.
8
[9]Beach R.F., Aerospace Power and Electronics Simulation Workshop, Concurrent Engineering Design practice foe Aerospace Power, NASA, 2003.
9
[10]Dirusso E., Passive Magnetic Bearings With Ferrofluid Stabilization, Lewis Research Center, Cleveland, Ohio, 1996.
10
[11]Clark D.J., Clark M.J., and Montague G.T., Overview of Magnetic Bearing Technology for Gas Turbine Engines, 2004.
11
[12]AMSAT-P 3D Magnetic Bearing Momentum Wheel, International Symposium on small Satellites, France, 1996.
12