Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
07
30
Compressive Behavior of a Glass/Epoxy Composite Laminates with Single Delamination
84
90
EN
A
Ghorbanpour Arani
Department of Mechanical Engineering, University of Kashan
aghorban@kashanu.ac.ir
R
Moslemian
Department of Mechanical Engineering, University of Kashan
A
Arefmanesh
Department of Mechanical Engineering, University of Kashan
The buckling and postbuckling behaviors of a composite beam with single delamination are investigated. A three-dimensional 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 non-linear one based on an incremental-iterative method. The large displacements have been taken into account in the nonlinear analysis. Instead of contact elements a new delamination closure device using rigid compression-only 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.
Delamination,Buckling,Postbuckling,Composite materials
http://jsm.iau-arak.ac.ir/article_514276.html
http://jsm.iau-arak.ac.ir/article_514276_a7c71154676d4dd1c4debfa1fb2bea93.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
07
30
Effect of Non-ideal Boundary Conditions on Buckling of Rectangular Functionally Graded Plates
91
97
EN
J
Mohammadi
Department of Mechanical Engineering, Islamic Azad University, Arak Branch
javad_mec@yahoo.com
M
Gheisary
Faculty of Engineering, Islamic Azad University, Khomein Branch
We have solved the governing equations for the buckling of rectangular functionally graded plates which one of its edges has small non-zero 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 in-plane load is assumed to be perpendicular to the edge which has non-ideal boundary conditions. Making use of the Linshtead-Poincare perturbation technique, the critical buckling loads are obtained. The results were then verified with the known data in the literature.
Buckling,Functionally graded plates,Non-ideal boundary conditions,Sliding support,Perturbation
http://jsm.iau-arak.ac.ir/article_514277.html
http://jsm.iau-arak.ac.ir/article_514277_003786a6ed524d76e952782337cf0d4d.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
30
Wave Propagation in a Layer of Binary Mixture of Elastic Solids
98
107
EN
R
Kumar
Department of Mathematics, Kurukshetra University
rajneesh_kuk@rediffmail.com
M
Panchal
Department of Mathematics, Kurukshetra University
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.
Mixture,Phase velocity,Attenuation coefficient,Specific loss,Amplitude ratios
http://jsm.iau-arak.ac.ir/article_514278.html
http://jsm.iau-arak.ac.ir/article_514278_7f981f24dba1d4ef08cac2f06ec1a1f8.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
30
Simple Solutions for Buckling of Conical Shells Composed of Functionally Graded Materials
108
117
EN
A
Lavasani
Department of Mechanical Engineering, Islamic Azad University, Arak Branch
ali_lavas@yahoo.com
Using Donnell-type 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.
Buckling,Conical shells,Functionally graded material,Axial load
http://jsm.iau-arak.ac.ir/article_514294.html
http://jsm.iau-arak.ac.ir/article_514294_c827422978e5bbe8b34129101bb9f899.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
01
Effect of Through Stationary Edge and Center Cracks on Static Buckling Strength of Thin Plates under Uniform Axial Compression
118
129
EN
A.V
Raviprakash
Department of Mechanical Engineering, Pondicherry Engineering College
avrp@sify.com
B
Prabu
Department of Mechanical Engineering, Pondicherry Engineering College
N
Alagumurthi
Department of Mechanical Engineering, Pondicherry Engineering College
M
Naresh
Department of Mechanical Engineering, Pondicherry Engineering College
A
Giriprasath
Department of Mechanical Engineering, Pondicherry Engineering College
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.
Thin plate structures,Buckling strength,Cracks
http://jsm.iau-arak.ac.ir/article_514295.html
http://jsm.iau-arak.ac.ir/article_514295_fe7cc2c1a387426d1e7e1b20b69b7fb7.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
30
Dynamic Stability of Functionally Graded Beams with Piezoelectric Layers Located on a Continuous Elastic Foundation
130
136
EN
N
Omidi
Department of Mathematics, Islamic Azad University, Khorramabad Branch
nader_omidi2002@yahoo.com
M
Karami Khorramabadi
Department of Mechanical Engineering, Islamic Azad University, Khorramabad Branch
mehdi_karami2001@yahoo.com
A
Niknejad
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
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.
Dynamic stability,Functionally graded beam,Elastic foundation,Piezoelectric layer
http://jsm.iau-arak.ac.ir/article_514296.html
http://jsm.iau-arak.ac.ir/article_514296_d8efcf92fe8d5f62f099181cf3ffb681.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
30
Geometrical Optimization of the Cast Iron Bullion Moulds Based on Fracture Mechanics
137
147
EN
A
Niknejad
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
niknejad@pnu.ac.ir
M
Karami Khorramabadi
Department of Mechanical Engineering, Islamic Azad University, Khorramabad Branch
mehdi_karami2001@yahoo.com
M.J
Sheikhpoor
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
S.A
Samieh Zargar
Faculty of Engineering, Payame Noor University (PNU), Yazd Branch
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 thermo-mechanical 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.
Optimization,Fatigue,Creep,Crack Propagation,Cast iron
http://jsm.iau-arak.ac.ir/article_514297.html
http://jsm.iau-arak.ac.ir/article_514297_6b0ab2098ec220cfa93a570a46e64d54.pdf
Islamic Azad University Arak Branch
Journal of Solid Mechanics
2008-3505
2008-7683
1
2
2009
06
30
Finite Element Analysis of Buckling of Thin Cylindrical Shell Subjected to Uniform External Pressure
148
158
EN
B
Prabu
Department of Mechanical Engineering, Pondicherry Engineering College
rathinam_pec@yahoo.in
N
Rathinam
Department of Mechanical Engineering, Pondicherry Engineering College
R
Srinivasan
Department of Mechanical Engineering, Pondicherry Engineering College
K.A.S
Naarayen
Department of Mechanical Engineering, Pondicherry Engineering College
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 mid-height of the cylindrical shell. ANSYS FE non-linear buckling analysis including both material and geometrical non-linearities is used to determine the critical buckling pressure. From the analysis it is found that when the maximum amplitude of imperfections is 1<em>t</em>, 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 1<em>t</em>, the inner half lobe axisymmetric imperfection pattern gives out the lowest critical buckling pressure when compared to the other imperfection patterns considered.
Thin cylindrical shell,Buckling pressure,Geometrical imperfections
http://jsm.iau-arak.ac.ir/article_514298.html
http://jsm.iau-arak.ac.ir/article_514298_f065c919775b0d302300094c3b88c733.pdf