2009
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Compressive Behavior of a Glass/Epoxy Composite Laminates with Single Delamination
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2
The buckling and postbuckling behaviors of a composite beam with single delamination are investigated. A threedimensional finite element model using the commercial code ANSYS is employed for this purpose. The finite elements analyses have been performed using a linear buckling model based on the solution of the eigenvalues problem, and a nonlinear one based on an incrementaliterative method. The large displacements have been taken into account in the nonlinear analysis. Instead of contact elements a new delamination closure device using rigid compressiononly beam elements is developed. Effect of delamination length, position through thickness and stacking sequence of the plies on the buckling and postbuckling of laminates is investigated. It has been found that significant decreases occur in the critical buckling loads after a certain value of the delamination length. The position of delamination and the fiber orientation also affect these loads.
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84
90


A
Ghorbanpour Arani
Department of Mechanical Engineering, University of Kashan
Department of Mechanical Engineering, University
Iran
aghorban@kashanu.ac.ir


R
Moslemian
Department of Mechanical Engineering, University of Kashan
Department of Mechanical Engineering, University
Iran


A
Arefmanesh
Department of Mechanical Engineering, University of Kashan
Department of Mechanical Engineering, University
Iran
Delamination
Buckling
Postbuckling
Composite materials
[[1] Kachanov L.M., 1976, Separation of composite materials, Mechanika Polimerov 5: 918922. ##[2] Chai H., Babcock C.D., Knauss W.G., 1981, Onedimensional modeling of failure in laminated plates by delamination buckling, International Journal of Solids and Structures 17:10691083. ##[3] Wang S.S., Zahlan N.M., Suemasu H., 1985, Compressive stability of delaminated random short fiber composites: Part IModeling and method of analysis, Journal of Composite Materials 19(4): 296316. ##[4] Wang S.S., Zahlan N.M., Suemasu H., 1985, Compressive stability of delaminated random short fiber composites: Part II Experimental and analytical results, Journal of Composite Materials 19(4): 317333. ##[5] Vizzini A.J., Lagace P.A., 1987, The buckling of a delaminated sublaminate on an elastic foundation, Journal of Composite Materials 21: 11061117. ##[6] Kutlu Z., Chang F.K., 1992, Modeling compression failure of laminated composites containing multiple throughwidth delaminations, Journal of Composite Materials 26: 350387. ##[7] Wang J.T., Cheng S.H., Lin C.C., 1995, Local buckling of delaminated beams and plates using continuous analysis, Journal of Composite Materials 29: 13741402. ##[8] Hwang S.F., Mao C.P., 1999, The delamination buckling of singlefiber system and interply hybrid composites, Composite Structures 46: 279287. ##[9] Zor M., 2003, Delamination width effect on buckling loads of simply supported wovenfabric laminated composite plates made of carbon/epoxy, Journal of Reinforced Plastics and Composites 22: 15351546. ##[10] Zor M., Sen F., Toygar M.E., 2005, An investigation of square delamination effects on the buckling behavior of laminated composite plates with a square hole by using threedimensional FEM analysis, Journal of Reinforced Plastics and Composites 24(11): 11191130. ##[11] Arman Y., Zor M., Aksoy S., 2006, Determination of critical delamination diameter of laminated composite plates under buckling loads, Composite Science and Technology 66(15): 29452953. ##[12] ANSYS 9, Theory Reference. ##[13] Southwell R.V., 1932, On the analysis of experimental observations in problems of elastic stability, in: Proceedings of the Royal Society of London 135: 601616. ##]
Effect of Nonideal Boundary Conditions on Buckling of Rectangular Functionally Graded Plates
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2
We have solved the governing equations for the buckling of rectangular functionally graded plates which one of its edges has small nonzero deflection and moment. For the case that the material properties obey a power law in the thickness direction, an analytical solution is obtained using the perturbation series. The applied inplane load is assumed to be perpendicular to the edge which has nonideal boundary conditions. Making use of the LinshteadPoincare perturbation technique, the critical buckling loads are obtained. The results were then verified with the known data in the literature.
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91
97


J
Mohammadi
Department of Mechanical Engineering, Islamic Azad University, Arak Branch
Department of Mechanical Engineering, Islamic
Iran
javad_mec@yahoo.com


M
Gheisary
Faculty of Engineering, Islamic Azad University, Khomein Branch
Faculty of Engineering, Islamic Azad University,
Iran
Buckling
Functionally graded plates
Nonideal boundary conditions
Sliding support
Perturbation
[[1] Reddy J.N., 2000, Analysis of functionally graded plates, International Journal for Numerical Methods in Engineering 47: 663684. ##[2] Najafizadeh M.M., Eslami M.R., 2002, Buckling analysis of circular plates of functionally graded materials based on first order theory, AIAA Journal 40(7): 14441450. ##[3] Javaheri R., Eslami M.R., 2002, Thermal buckling of functionally graded plates, AIAA Journal 40(1): 162169. ##[4] Gorman D.J., 2000, Free vibration and buckling of inplane loaded plates with rotational elastic edge support, Journal of Sound and Vibration 229(4): 755773. ##[5] Pakdemirli M., Boyaci H., 2002, Effect of nonideal boundary conditions on the vibrations of continuous systems, Journal of Sound and Vibration 249: 815823. ##[6] Pakdemirli M., Boyaci H., 2003, Nonlinear vibrations of a simplesimple beam with a nonideal support in between, Journal of Sound and Vibration 268: 331341. ##[7] Aydogdu M., Ece M.C., 2006, Buckling and vibration of nonideal simply supported rectangular isotropic plates, Mechanics Research Communications 33: 532540. ##[8] Nayfeh A.H., 1981, Introduction to Perturbation Techniques, Wiley, New York. ## ##]
Wave Propagation in a Layer of Binary Mixture of Elastic Solids
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2
This paper concentrates on the propagation of waves in a layer of binary mixture of elastic solids subjected to stress free boundaries. Secular equations for the layer corresponding to symmetric and antisymmetric wave modes are derived in completely separate terms. The amplitudes of displacement components and specific loss for both symmetric and antisymmetric modes are obtained. The effect of mixtures on phase velocity, attenuation coefficient, specific loss and amplitude ratios for symmetric and antisymmetric modes is depicted graphically. A particular case of interest is also deduced from the present investigation.
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98
107


R
Kumar
Department of Mathematics, Kurukshetra University
Department of Mathematics, Kurukshetra University
Iran
rajneesh_kuk@rediffmail.com


M
Panchal
Department of Mathematics, Kurukshetra University
Department of Mathematics, Kurukshetra University
Iran
Mixture
Phase velocity
Attenuation coefficient
Specific loss
Amplitude ratios
[[1] Truesdell C., 1996, Mechanical basis of diffusion, Journal of Chemical Physics 37: 23362344. ##[2] Truesdell C., Toupin R., 1960, Handbuch der Physik, 3/1: 469472, 567 568, 612614, Springer. ##[3] Bowen R.M., 1976, Theory of mixtures, in: Continuum Physics,edited byA.C.Eringen, 3, Academic Press, New York. ##[4] Atkin R.J., Craine R.E., 1976, Continuum theories of mixtures: Applications, Journal of Applied Mathematics 17(2): 153207. ##[5] Atkin R.J., Craine R.E., 1976, Continuum theories of mixtures: Basic theory and historic development, Quarterly Journal of Mechanics and Applied Mathematics 29: 209245. ##[6] Bedford A., Drumheller D.S., 1983, Theory of immiscible and structured mixtures, International Journal of Engineering Science 21: 863960. ##[7] Samohyl I., 1987, Thermodynamics of Irreversible Processes in Fluid Mixtures, Teubner Verlag, Leibzig. ##[8] Rajagopal K.R., Tao L., 1995, Mechanics of Mixtures, World Scientific, Singapore. ##[9] Green A.E., Steel T.R., 1966, Constitutive equations for interacting continua, International Journal of Engineering Science 4: 483500. ##[10] Steel T.R., 1967, Applications of a theory of interacting continua, Quarterly Journal of Mechanics and Applied Mathematics 20: 5772. ##[11] Bedford A., Stern M., 1972, A multicontinuum theory for composite elastic materials, Acta Mechanica 14: 85102. ##[12] Bedford A., Stern M., 1972, Towards a diffusing continuum theory of composite elastic materials, ASME Transactions, Journal of Applied Mechanics 38: 814. ##[13] Iesan D., Quintanilla R., 1994, Existance and continuous dependence results in the theory of interacting continua, Journal of Elasticity 36: 8598. ##[14] Tiersten H.F., Jahanmir M., 1977, A theory of composite modeled as interpenetrating solid continua, Archive for Rational Mechanics and Analysis 65: 153192. ##[15] Iesan D., 1994, On the theory of mixtures of elastic solids, Journal of Elasticity 35: 251268. ##[16] Iesan D., 1996, Existance theorems in the theory of mixtures, Journal of Elasticity 42: 145163. ##[17] Ciarletta M., 1998, On mixtures of nonsimple elastic solids, International Journal of Engineering Science 36: 655668. ##[18] Ciarletta M., Passarella F., 2001, On the spatial behavior in dynamics of elastic mixtures, European Journal of Mechanics A/Solids 20: 969979. ##[19] Iesan D., 2004, On the theory of viscoelastic mixtures, Journal of Thermal Stresses 27: 11251148. ##[20] Quintanilla R., 2005, Existance and exponential decay in the linear theory of viscoelastic mixtures, European Journal of Mechanics A/Solids 24: 311324. ##[21] Iesan D., 2007, A theory of thermoviscoelastic composites modelled as interacting cosserat continua, Journal of Thermal Stresses 30: 12691289. ##[22] Kolsky H., 1963, Stress Waves in Solids, Clarendon Press, Oxford Dover Press, New York. ##[23] Graff K.F., 1975, Wave Motion in Elastic Solids, Clarendon Press, Oxford. ##]
Simple Solutions for Buckling of Conical Shells Composed of Functionally Graded Materials
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Using Donnelltype shell theory a simple and exact procedure is presented for linear buckling analysis of functionally graded conical shells under axial compressive loads and external pressure. The solution is in the form of a power series in terms of a particularly convenient coordinate system. By analyzing the buckling of a series of conical shells, under various boundary conditions and different material coefficients, the validity of the presented procedure is confirmed.
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108
117


A
Lavasani
Department of Mechanical Engineering, Islamic Azad University, Arak Branch
Department of Mechanical Engineering, Islamic
Iran
ali_lavas@yahoo.com
Buckling
Conical shells
Functionally graded material
Axial load
[[1] Siede, P., Calif, L.A., 1956, Axisymetric buckling of circular cones under axial compression, ASME Transactions, Journal of Applied Mechanics 23: 625628. ##[2] Lackman L., Renzien J., 1960, Buckling of circular cones under axial comperession, ASME Transactions, Journal of Applied Mechanics 27: 458460. ##[3] Singer J., 1961, Buckling of circular conical shells under axisymmetrical external pressure, Journal of Mechanical Engineering Science 3: 330339. ##[4] Singer J., 1965, Buckling of circular conical shells under uniform axial compression, AIAA Journal 3: 985987. ##[5] Weigarten V.I., Seide P., 1965, Elastic stability of thin walled cylindrical and conical shells under combined external pressure and axial compression, AIAA Journal 3: 913920. ##[6] Weigarten V.I., Seide P., 1965, Elastic stability of thin walled cylindrical and conical shells under combined external pressure and axial compression, AIAA Journal 3: 11181125. ##[7] Baruch M., Harari O., Singer J., 1970, Low buckling loads of axially compressed conical shells, ASME Transactions, Journal of Applied Mechanics 37: 384392. ##[8] Tani J., Yamaki Y., 1970, Buckling of truncated conical shells under axial compression, AIAA Journal 8: 568570. ##[9] Singer J., 1966, Buckling of damped conical shells under external pressure, AIAA Journal 4, 328337. ##[10] Baruch M., Singer J., 1965, General instability of stiffened conical shells under hydrostatic pressure, Aeronautics Quarterly 26: 187204. ##[11] Weigarten V.I., Morgan E.J., Seide P., 1965, Elastic stability of thin walled cylindrical and conical shells under axial compression, AIAA Journal 3: 500505. ##[12] Tong Liyong, 1988, Buckling and vibration of conical shells composed of composite materials, Ph.D. Thesis, Beijing University of Aeronautics and astronautics. ##[13] Reddy J. N., Praveen G. N., 1998, Nonlinear transient thermoelastic analysis of functionally graded ceramicmetal plates, International Journal of Solids and Structures 35: 44674476. ##[14] Tong L., Tabarrok B., Wang T.K., 1992, Simple solution for buckling of orthotropic conical shells, International Journal of Solids and Structures 29: 933946. ##]
Effect of Through Stationary Edge and Center Cracks on Static Buckling Strength of Thin Plates under Uniform Axial Compression
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2
Thin plate structures are more widely used in many engineering applications as one of the structural members. Generally, buckling strength of thin shell structures is the ultimate load carrying capacity of these structures. The presence of cracks in a thin shell structure can considerably affect its load carrying capacity. Hence, in this work, static buckling strength of a thin square plate with a centre or edge crack under axial compression has been studied using general purpose Finite Element Analysis software ANSYS. Sensitivity of static buckling load of a plate with a centre or a edge crack for crack length variation and its vertical and horizontal orientations have been investigated. Eigen buckling analysis is used to determine the static buckling strength of perfect and cracked thin plates. First, bifurcation buckling loads of a perfect thin plate with its mode shapes from FE eigen buckling analysis are compared with analytical solution for validating the FE models. From the analysis of the cracked thin plates, it is found that vertical cracks are more dominant than horizontal cracks in reducing buckling strength of the thin plates. Further, it is also found that as the crack length increases, buckling strength decreases.
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118
129


A.V
Raviprakash
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran
avrp@sify.com


B
Prabu
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran


N
Alagumurthi
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran


M
Naresh
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran


A
Giriprasath
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran
Thin plate structures
Buckling strength
Cracks
[[1] Suneel Kumar M., Alagusundaramoorthy P., Sundaravadivelu R., 2007, Ultimate strength of square plate with rectangular opening under axial compression, Journal of Naval Architecture and Marine Engineering 4(1): 1526. ##[2] Timoshenko S.P., Gere J.M., 1965, Theory of Elastic Stability, McGrawHill Publications, Second Edition. ##[3] Brush Don O., Almroth Bo O., 1975, Buckling of Bars, Plates and Shells, McGrawHill, International Student Edition, Tokyo. ##[4] Bushnell D., 1985, Computerized Buckling Analysis of Shells, Martinus Nijhoff Publishers, Dordrecht. ##[5] Estekanchi H.E, Vafai A., 1999, On the buckling of cylindrical shells with through cracks under axial load, ThinWalled Structures 35: 255265. ##[6] Satish Kumar Y.V., Paik J.K., 2004, Buckling analysis of cracked plate using hierarchical trigonometric functions, ThinWalled Structures 42:687700. ##[7] Paik J.K., Satish Kumar Y.V., Lee J.M., 2005, Ultimate strength of cracked plate elements under axial compression or tension, ThinWalled Structures 43: 237272. ##[8] Kacianauskas R., Stupak E., Stupak S., 2005, Application of adaptive finite elements for solving elastic plastic problem of SENB specimen, Mechanika 51(1): 1822. ##[9] Robert D. Cook, David S. Malkus, Michael E. Plesha, Robert J. Witt, 2002, Concepts and Applications of Finite Element Analysis, John Wiley & Sons Publications (Asia) PTE Ltd., Singapore, Fourth Edition. ##[10] Brighenti R., 2005, Buckling of cracked thin plates under tension and compression, ThinWalled Structures 43(2): 209224. ##[11] ANSYS user manual 11.0. ## ##]
Dynamic Stability of Functionally Graded Beams with Piezoelectric Layers Located on a Continuous Elastic Foundation
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2
This paper studies dynamic stability of functionally graded beams with piezoelectric layers subjected to periodic axial compressive load that is simply supported at both ends lies on a continuous elastic foundation. The Young’s modulus of beam is assumed to be graded continuously across the beam thickness. Applying the Hamilton’s principle, the governing dynamic equation is established. The effects of the constituent volume fractions, the influences of applied voltage, foundation coefficient and piezoelectric thickness on the unstable regions are presented.
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130
136


N
Omidi
Department of Mathematics, Islamic Azad University, Khorramabad Branch
Department of Mathematics, Islamic Azad University
Iran
nader_omidi2002@yahoo.com


M
Karami Khorramabadi
Department of Mechanical Engineering, Islamic Azad University, Khorramabad Branch
Department of Mechanical Engineering, Islamic
Iran
mehdi_karami2001@yahoo.com


A
Niknejad
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
Faculty of Engineering, Payame Noor University
Iran
Dynamic stability
Functionally graded beam
Elastic foundation
Piezoelectric layer
[[1] Bailey T., Hubbard Jr.J.E., 1985, Distributed piezoelectricpolymer active vibration control of a cantilever beam. Journal of Guidance Control and Dynamic 8: 605611. ##[2] Crawley E.F., de Luis J., 1987, Use piezoelectric actuators as elements of intelligent structures, AIAA Journal 8: 13731385. ##[3] Shen M.H., 1994, Analysis of beams containing piezoelectric sensors and actuators, Smart Materials and Structures 3: 439347. ##[4] Pierre C., Dowell E.H., 1985, A study of dynamic instability of plates by an extended incremental harmonic balance method, ASME Transactions, Journal of Applied Mechanics 52: 693697. ##[5] Liu G.R., Peng X.Q., Lam K.Y., 1999, Vibration control simulation of laminated composite plates with integrated piezoelectrics, Journal of Sound and Vibration 220(5): 827846. ##[6] Tzou H.S., Tseng C.I., 1990, Distributed piezoelectric sensor/actuator design for dynamic measurement/control of distributed parameter system: A piezoelectric finite element approach, Journal of Sound and Vibration 138: 1734. ##[7] Ha S.K., Keilers C., Chang, F.K., 1992, Finite element analysis of composite structures containing distributed piezoceramic sensors and actuators, AIAA Journal 30: 772780. ##[8] Bolotin V.V., 1964, The Dynamic Stability of Elastic Systems, Holden Day, San Francisco. ##[9] Briseghella L., Majorana C.E., Pellegrino C., 1998, Dynamic stability of elastic structures: A finite element approach, Computers and Structures 69: 1125. ##[10] Takahashi K., Wu M., Nakazawa N., 1998, Vibration, buckling and dynamic stability of a cantilever rectangular plate subjected to inplane force, Engineering Mechanics 6: 939953. ##[11] Zhu J., Chen C., Shen Y., Wang S., 2005, Dynamic stability of functionally graded piezoelectric circular cylindrical shells, Materials Letters 59: 477485. ##[12] Reddy J.N., Praveen G.N., 1998, Nonlinear transient thermoelastic analysis of functionally graded ceramicmetal plates, International Journal of Solids and Structures 35: 44674476. ## ##]
Geometrical Optimization of the Cast Iron Bullion Moulds Based on Fracture Mechanics
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2
In this paper, the causes of the crack initiation in cast iron bullion moulds in Meybod Steel Corporation are investigated and then some new geometrical models are presented to replace the current moulds. Finally, among the new presented models and according to the life assessment, the best model is selected and suggested as the replaced one. For this purpose, the three recommended moulds were modeled and analyzed by ANSYS software. First, a thermal analysis and then a thermomechanical coupled field analysis were performed on each three model. The results of the analysis are used to determine the critical zone. The critical zone is selected on the symmetric axis of the inner surface of the mould. By comparing the principle stress contours and temperature distribution contours of three models, one of the suggested models was selected as optimized geometrical model. Then, the crack modeling and the life assessment on the optimized model were implemented and the total life of the model was calculated. Comparison of the life of the optimized and the initial models shows an increase in the life of the suggested model. The results are verified with the experiments.
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137
147


A
Niknejad
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
Faculty of Engineering, Payame Noor University
Iran
niknejad@pnu.ac.ir


M
Karami Khorramabadi
Department of Mechanical Engineering, Islamic Azad University, Khorramabad Branch
Department of Mechanical Engineering, Islamic
Iran
mehdi_karami2001@yahoo.com


M.J
Sheikhpoor
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
Faculty of Engineering, Payame Noor University
Iran


S.A
Samieh Zargar
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
Faculty of Engineering, Payame Noor University
Iran
Optimization
Fatigue
Creep
Crack Propagation
Cast iron
[[1] Niknejad A., Samieh Zargar S.A., Sheikhpour M.J., 2009, Investigation of the life assessment and the crack propagation in the molds of cast iron bar, in: Proceeding of the 17th International Conference on Mechanical Engineering, Tehran, Iran (in Persian). ##[2] Ishihara S., Nan Z.Y., McEvily A.J., Goshima T., Sunada S., 2008, On the initiation and growth behavior of corrosion pits during corrosion fatigue process of industrial pure aluminum, International Journal of Fatigue 30: 16591668. ##[3] Xu Y., Yuan H., 2008, Computational analysis of mixedmode fatigue crack growth in quasibrittle materials using extended finite element methods, Engineering Fracture Mechanics 30: 17801786. ##[4] Ranganathan N., Chalon F., Meo S., 2008, Some aspects of the energy based approach to fatigue crack propagation, International Journal of Fatigue 30: 19211929. ##[5] Wang Y., Cui W., Wu X., Wang F., Huang X., 2008, The extended McEvily model for fatigue crack growth analysis of metal structures, International Journal of Fatigue 30: 18511860. ##[6] Borrego L.P., Ferreira J.M., Costa J.M., 2008, Partial crack closure under block loading, International Journal of Fatigue 30: 17871796. ##[7] Jones R., Molent L., Pitt S., 2008, Similitude and the Paris crack growth law, International Journal of Fatigue 30: 18731880. ##[8] Kagawa H., Morita A., Matsuda T., Kubo S., 2008, Fatigue crack propagation behavior in fourpoints bending specimens with multiple parallel edge notches at regular intervals, Engineering Fracture Mechanics 75: 45944609. ##[9] Herrera A.G., Zapatero J., 2008, Tridimensional numerical modeling of plasticity induced fatigue crack closure, Engineering Fracture Mechanics 75: 45134528. ##[10] Cojocaru D., Karlsson A.M., 2008, An objectoriented approach for modeling and simulation of crack growth in cyclically loaded structures, Advances in Engineering Software 39: 9951009. ##[11] Liljedahl C.D.M., Fitzpatrick M.E., Edwards L., 2008, Residual stresses in structures reinforced with adhesively bonded straps designed to retard fatigue crack growth, Composite Structures 86: 344355. ##[12] Uematsu Y., Tokaji K., Kawamura M., 2008, Fatigue behavior of Sicparticulatereinforced aluminum alloy composites with different particle sizes at elevated temperatures, Composites Science and Technology 68: 27852791. ##[13] Castillo E., Canteli A.F., Pinto H., RuizRipoll M.L., 2008, A statistical model for crack growth based on tension and compression Wohler fields, Engineering Fracture Mechanics 75: 44394449. ##[14] Fan F., Kalnaus S., Jiang Y., 2008, Modeling of fatigue crack growth of stainless steel 304L, Mechanics of Materials 40: 961973. ##[15] Bogdanski S., Lewicki P., 2008, 3D model of liquid entrapment mechanism for rolling contact fatigue cracks in rails, Wear 265: 13561362. ##[16] Giner E., Sukumar N., Denia F.D., Fuenmayor F.J., 2008, Extended finite element method for fretting fatigue crack propagation. International Journal of Solids and Structures 45: 56755687. ##[17] Mirzaei M., Niknejad A., 2004, Investigation of the crack growth and life assessment of the copper slag pot, in: Proceeding of the 12th International Conference on Mechanical Engineering, Tehran, Iran (in Persian). ## ##]
Finite Element Analysis of Buckling of Thin Cylindrical Shell Subjected to Uniform External Pressure
2
2
One of the common failure modes of thin cylindrical shell subjected external pressure is buckling. The buckling pressure of these shell structures are dominantly affected by the geometrical imperfections present in the cylindrical shell which are very difficult to alleviate during manufacturing process. In this work, only three types of geometrical imperfection patterns are considered namely (a) eigen affine mode imperfection pattern, (b) inward half lobe axisymmetric imperfection pattern extended throughout the height of the cylindrical shell and (c) local geometrical imperfection patterns such as inward dimple with varying wave lengths located at the midheight of the cylindrical shell. ANSYS FE nonlinear buckling analysis including both material and geometrical nonlinearities is used to determine the critical buckling pressure. From the analysis it is found that when the maximum amplitude of imperfections is 1t, the eigen affine imperfection pattern gives out the lowest critical buckling pressure when compared to the other imperfection patterns considered. When the amplitude of imperfections is above 1t, the inner half lobe axisymmetric imperfection pattern gives out the lowest critical buckling pressure when compared to the other imperfection patterns considered.
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148
158


B
Prabu
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran
rathinam_pec@yahoo.in


N
Rathinam
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran


R
Srinivasan
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran


K.A.S
Naarayen
Department of Mechanical Engineering, Pondicherry Engineering College
Department of Mechanical Engineering, Pondicherry
Iran
Thin cylindrical shell
Buckling pressure
Geometrical imperfections
[[1] Ross C.T.F., Little A.P.F., Adeniyi K.A., 2005, Plastic buckling of ringstiffened conical shell under eternal hydrostatic pressure, Ocean Engineering 32:2136. ##[2] Ross C.T.F., Little A.P.F., Allsop R., Smith, C., Engelhardt M., 2007, Plastic General instability of ringreinforced conical shells under uniform external pressure, Marine Technology 44(4): 268277. ##[3] Schiender W., Brede A., 2005, Consistent equivalent geometric imperfections for the numerical buckling strength verification of cylindrical shells under uniform external pressure, ThinWalled Structures 43(2): 175188. ##[4] Timoshenko P.S., Gere M.J., 1965, Theory of Elastic Stability, McGrawHill Publications, Second Edition, Singapore. ##[5] Brush D.O., Almroth B.O., 1975, Buckling of Bars, Plates and Shells, Chapter 5, McGrawHill, New York. ##[6] Bushnell D., 1985, Computerized Buckling Analysis of Shells, Martinus Nijhoff Publishers, Doedrecht. ##[7] Teng J.G., Song C.Y., 2001, Numerical models for nonlinear analysis of elastic shells with eigen modeaffine imperfections, International Journal of Solids and Structures 38: 32633280. ##[8] Featherston C.A., 2003, Imperfection sensitivity of curved panels under combined compression and shear, International Journal of NonLinear Mechanics 38: 225238. ##[9] Kim SeungEock, Kim ChangSung, 2002, Buckling strength of the cylindrical shell and tank subjected to axially compressive loads, ThinWalled Structures 40: 329353. ##[10] Khelil, 2002, Buckling of steel shells subjected to nonuniform axial and pressure loadings, ThinWalled Structures 40: 955970. ##[11] Pircher M., Berry P.A., Ding X., Bridge R.Q., 2001, The shape of circumferential weldinduced imperfections in thinwalled steel silos and tanks, ThinWalled Structures 39(12): 9991014. ##[12] Koiter W.T., 2001, Elastic stability and postbuckling behaviour, Journal of Structural Engineering 127(10): 1129 1136. ##[13] Khamlichi A., Bezzazi M., Limam A., 2004, Buckling of elastic cylindrical shells considering the effect of localized axisymmetric imperfections, ThinWalled Structures 42: 10351047. ##[14] Schiender W., 2006, Stimulating equivalent geometric imperfections for the numerical buckling strength verification of axially compressed cylindrical steel shells, Comput. Mech. 37: 530536. ##[15] Hutchinson J.W., Tennyson R.C., Muggeridge D.B., 1971, Effect of local axisymmetrical imperfection on the buckling behavior of a circular cylindrical shell under axial compression, AIAA Journal 9: 4852. ##[16] Amazigo J.C., Budiansky B., 1972, Asymptotic formulas for the buckling stresses of axially compressed cylinders with localized or random axisymmetric imperfections, ASME Transactions, Journal of Applied Mechanics 39: 179184. ##[17] Shen H.S., Li Q.S., 2002, Thermo mechanical post buckling of shear deformable laminated cylindrical shells with local geometric imperfections, International Journal of Solids and Structures 39: 45254542. ##[18] Song C.Y., Teng J.G., Rotter J.M., 2004, Imperfections sensitivity of thin elastic cylindrical shells subjected to axial compression, International Journal of Solids and Structures 41: 71557180. ##[19] Arbocz J., Stranes J.H., 2004, On a verified highfidelity analysis for axially compressed cylindrical shells, in: 45th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics& Materials Conference, 1922 April 2004, Palm Springs, California, AIAA 20041712. ##[20] ANSYS 10 User Manual. ## ##]